FAQs on Freshwater Aquarium
Circulation
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Best approach for current and O2?
7/20/17
Hello:
<Hey Jude>
Just wondering what is the best for a 38 gallon tall tank with two angels, 6
Glowlight tetras and one Medusa Pleco.
If I need current for the Pleco what is the best way to obtain that?
<Complete circulation... pulling water from the bottom, to top... and
redundancy. Two mechanisms at work at the same time. Perhaps an outside power
filter and... Oh, I see you answer the question below!>
I have nothing in there now, but the filter which is an Aquaclear for a 70
gallon. I am thinking of lowering the water a few inches to get splash.
Would that help like an air stone would?
<I would add the airstone here>
Just wondering what is best for the Pleco at the bottom and aeration overall?
Thanks
Judy
<As stated. Bob Fenner>
Advice on filter/water circulation for 55
gallon 11/13/09
Hello, very comprehensive site, - through the years I found answers to
many of my questions here! - Thanks!
<Glad to have been useful.>
There is a snapshot of my set up:
55 gallon
planted with Anacharis, Anubias, Anubias nano, floating Riccia and some
duckweed
decorated with driftwood and rocks
2 heaters (temperature at 78-80)
Undergravel filter driven by a small loud pump
Livestock:
One 5 inch plecostomus
One 8 inch Jack Dempsey
One 7 inch Texas Cichlid
One Ropefish (about 14 inches)
<Poor thing! These gentle, gregarious fish are best kept in groups,
and certainly away from cichlids and other aggressive fish.>
One Polypterus senegalus - 6.5 inches
<I've seen (Labidochromis) cichlids strip the fins from Bichirs,
so to be honest, this the Bichir/Cichlid combination isn't one I
recommend.>
Five silver dollars - about 2 inch diameter each
One 8 inch Leporinus fascinates
<Leporinus fasciatus can become extremely aggressive, and is a known
fin-biter (apparently natural behaviour). I wouldn't be keeping
this with Bichirs or Ropefish, and while I've seen them mixed with
cichlids, I've heard of the odd specimen that has become so
aggressive it's caused serious mayhem.>
I think I'm barely not overstocking tank or is it overstocked?
<In 55 gallons? Overstocked, and then some. More importantly, the
selection of fish isn't at all wise.>
Cichlids compete for space but never gone worse then a lot of shaking
at each other and some mild chasing. (prior to this set up i tried a
species tank of Jewel Cichlids - that was "Battlefield
Laterite" compared to what I got now :) )
<Well, the Bichir is still a baby, as are the Silver Dollars, so I
wouldn't get too excited about a "job well done" just
yet.>
I used an old Emperor 400 filter with two BioWheels, except it was
second-hand and didn't have BioWheels and was very very loud - and
finally was taken out of the tank - 4 months ago)
Water changes - at least every 2 weeks change of 5 gallons of water
Ammonia is 0, Nitrites 0, i haven't measured PH in a while. Should
be pretty hard, since in MN water comes of the limestone, but driftwood
should compensate for at least some of it.
<No, driftwood doesn't work this way. Driftwood will lower the
pH of soft water by releasing tannic acids; it does not substantially
soften water though. For one thing, insufficient surface area.>
No loss of fish since set up of the tank 1 year ago with this exact
livestock (they were much smaller, but the y also lived then in a 30
gallon).
<You got lucky. So far.>
4 months after the Emperor Filter was taken out of the tank I noticed
slimy dark green clumps growing among the floating Riccia. Looks like
green-blue algae to me. Smells nasty - like a swamp (previously tank
had only a clean "aquarium" smell - which in larger amounts
can be found in very good LFS places).
<Blue green algae.>
Is it a blue-green algae?
<Yes.>
Is there is a way to combat it with chemical/biological measures?
<Almost certainly -- as in I'd put $100 down on this -- the
problems are two-fold: insufficient water movement, and very high
levels of nitrate and phosphate. Blue-green algae is almost a
"standard issue problem" with overstocked cichlid tanks, and
often a precursor to bigger problems including
Hexamita/Hole-in-the-Head, since the conditions that promote blue-green
algae are the same ones that reduce the vitality of cichlids.>
Does any fish eat it?
<Not really, no.>
Plecostomus does not - drowned one clump but he showed no interest.
<Plec-type catfish are the biggest con in the game. They are more
likely to *cause* an algae problem than fix one. Think about this for a
moment. Algae does best in tanks with lots of nitrate and phosphate.
Plecs are big, messy animals. Put the two together and you have happy
algae. In tanks with big, messy fish algae removal is a two-step
process: install bright lighting so that you can add Indian Fern and
other algae-busting plants, and then use an algae sponge to remove
whatever is left over. That's it. Those are the options. Nerite
snails would be great, but the cichlids would likely eat them, but for
$ a piece, you might feel they're worth a shot. Do read here:
http://www.wetwebmedia.com/ca/volume_6/volume_6_3/fwalgae.html
>
Also clear parts of water surface are covered with a dimly iridescent
film, like spilled grease or gasoline. What could that be?
<If it's golden, then likely Diatoms.>
It does disappear after water change, but comes back within 2-3
feedings.
<Proves my point: it's related to eutrophic conditions in the
aquarium.
Hang-on-the-back filters are rubbish in terms of water circulation and
I can't recommend them for fish tanks with big fish. I have no idea
why they're so popular in America; you hardly see them in Europe,
and frankly,
I don't miss them! You need massive water circulation in this tank,
I'd say 8 times the volume of the tank in turnover per hour. Adding
a big canister filter, ideally through a reverse-flow undergravel,
would be the best
solution. Water changes need to be massive. And last but not least, you
need to thin out your livestock. For a 55 gallon tank, you have
something like three times the number of fish you can keep safely. The
"inch per
gallon" rule applies to fish around an inch long, i.e., Neons,
Guppies, etc. It OBVIOUSLY doesn't apply to big cichlids and
catfish. Think about this for a moment. One Oscar is about 18 inches
long when mature, as are twelve Neon tetras laid end to end. Which
needs more aquarium space?>
Since largest fish are omnivorous - I feed a mix of bloodworms/mosquito
larvae/spinach/peas/algae wafers/occasional feeder or shrimp.
<Why are you using feeder fish? This has been explained endlessly in
books and magazines, but let's do it one more time. Feeder fish are
"parasite bombs". Any fish bred for a few cents obviously
won't be kept in good, hygienic conditions. Furthermore, feeder
fish enhance aggression. Most importantly of all, cyprinids (goldfish,
minnows, etc) are high in fat and thiaminase, and together these cause
MAJOR health problems. Pick up any book on aquarium fish health and it
will state in no uncertain terms that feeder fish are extremely bad.
Bob Fenner has reported that a majority of non-old-age deaths of
Lionfish are caused by goldfish feeders. So there's no real
surprise here, and I can't for the life of me think why people
still use them. They aren't even sold in England, and haven't
been for a good twenty years. While we don't get much right in this
country, I think on the feeder fish front we're definitely wise. If
you want to offer live foods, choose something known to be safe, such
as earthworms.>
Meanwhile fish look healthy and eat/behave as usual.
<For how much longer...? As I say, blue-green algae are common in
tanks with poor water flow, limited oxygen, high nitrate, and high
phosphate.
That's a cocktail of trouble. As fish grow, they become more
demanding in terms of aquarium resources, so the fact they've been
healthy when younger doesn't mean they'll stay healthy as they
grow older.>
I reasoned that the undergravel filter alone does not serve the tank
and I need to shell out for a new filter. This is what I'm looking
for:
1. large enough throughput
2. preferred some kind of underwater water output - otherwise may get
loud as water evaporates quickly in the summer.
3. quiet (tank is in the living room of a co-op and my mates will fry
my cichlids if I raise DB level of the house again :) )
4. under $100 of at least under $150
<Since I'm not in the US I can't really price things up for
you. But I'd mention that a Classic Eheim 2217 costs around 27 UK
Pounds and has a turnover of over 250 gallons/hour. A couple of those
would really help.
They're built to last and very quiet. So while pricey, Eheim
filters are by far the best value since they routinely run for over ten
years without problems. There are plenty of cheaper options, and a
budget external canister plugged into a reverse-flow undergravel
shouldn't break the bank.>
What would be your recommendations?
<See above. Alternatively, take back a bunch of fish, and keep two
or three fish suited to this tank, maybe the JD, the Texas, and the
Plec (but anything with the Plec is going to be filthy). Personally,
I'd have stuck
with the Bichir, three Ropefish, and maybe a school of Congo Tetras or
Rainbowfish for the midwater. I'd still have space for a
Bristlenose Plec, which is smaller, cleaner, and does remove some
algae.>
what else can improve water quality of the tank?
<Many, many things.>
Huge Thanks for help! - Elena
<Hope this helps. Cheers, Neale.>
Re: <sic> advise on filter/water
circulation for 55 gallon 11/13/09
Thanks for the answer!
<You're welcome.>
I'll work on thinning the tank - frankly I knew long ago it's
far from the best mix, but as it happens Cichlids' antics grow on
you.
<Yes indeed. But they *are* demanding fish in so many ways.>
Bichir was the first fish in this set up - bought him 3 years ago at a
size of a matchstick, and I'm bent on keeping him while getting
better tank mates.
<Cool.>
1. Trade in JD and Texas cichlids, potentially trade in the Leporinus
(I've seen aggressive behavior from some in the stores and while
mine is peaceful, it could be just the cichlid presence that makes him
so)
<Likely depends on the fish, the environment, and indeed as you say,
the companions.>
3. if possible get more ropefishes - 1 or 2 more, It's all i can
afford at the moment.
<Maybe swap the cichlids for them? Trust me: get three, and a nice
hollow ornament, even a halved flowerpot, they can hide in, and
you'll be charmed by them. They enjoy hanging about in groups, all
tangled up, with their heads poking out of their cave.>
4. I'd like to may be get a few smaller cichlids that would display
personality and add to the tank?
<Pelvicachromis spp. work great with Bichirs and Ropefish, as would
anything reasonably small and mellow, e.g., Keyholes, Flag Acara, maybe
even Blue Acara or a Firemouth (these are aggressive when breeding, but
otherwise easy-going).>
For all my love to Polypteridae - they are not as colorful and fun to
watch as cichlids.
<Understandable. Congo Tetras and Leopard Bushfish (Ctenopoma
acutirostre) are my favourites to fill this niche. Bushfish are easy to
feed on wet-frozen bloodworms and other such treats, and don't need
feeder fish, despite what some might suggest. Congo tetras and Bushfish
are from Africa, so together with the Bichirs and Ropefish, you have a
nice African scene.
Add some Anubias and floating Indian fern for shade, and maybe a school
of Dwarf Synodontis on the catfish front... what more can you ask
for?>
I think of a couple Convicts, may be a Kribensis (couple),
<Convicts wouldn't be more choice at all; Kribs, and indeed
other Pelvicachromis spp., like Pelvicachromis taeniatus, would be fine
choices.
Since you're in MN, you might get in touch with one of the fish
clubs there. I happen to be talking to one of them in Minneapolis in
January, so know of at least one. Fish clubs are a great way to swap
unwanted fish, to obtain plants and fish cheaply, and to track down
"rare" fish you don't see in pet shops. But having said
that, all the fish I've mentioned so far are in the trade and easy
to order, even if they're not in the tanks this very day.>
Please advise!
Thanks Again! - Elena
<Cheers, Neale.>
Re: <sic> advise on filter/water
circulation for 55 gallon 11/14/09
Neale,
<Elena,>
this will be the last email from me - I got more then enough info
already!
<Oh!>
what about a Black Ghost Knife as a Bichir/Ropefishes companion in 55 g
- MonsterFishkeeper forum recommended them as suitable tank mates for
bichirs (and they are probably most beautiful fish ever!) - may this
work or is 55 gallon too small for BGK?
<In terms of temperament, yes, non-aggressive Bichir species can
cohabit with Black Ghost Knifefish. HOWEVER, do understand that
Apteronotus albifrons is one of the most delicate fish commonly traded,
and most specimens (surely 90% of them) die within a year. Given these
fish can live 20 years and get to 45 cm or so in length, that's a
sign folks don't keep 'em well. They are extremely sensitive to
"old" water with high nitrate levels. They come from shallow,
fast water habitats around rapids and waterfalls, so expect lots and
lots of oxygen and water current. While your Bichirs would be fine with
that provided the tank wasn't too deep (Bichirs are air breathers,
so have to be able to swim to the surface) if you are having problems
with blue-green algae, then it's likely your current filtration
system is far inadequate for a Black Ghost. Oh, and it should go
without saying that apart from inoffensive dwarf cichlids, you
can't reliably mix cichlids with Black Ghosts. Sure, some folks do,
but as/when they keep 'em alive for twenty years, then I'll
accept it's do-able. For the most part, cichlids are poor tankmates
for Black Ghosts. Too much competition for living space and food, and
high nitrate levels are even more lethal to Apteronotus than they are
to cichlids. Exceptions might be made for cichlids from similar
fast-water habitats, e.g., Steatocranus and Nanochromis, but these are
difficult fish to keep at the best of times, and not viable in the
average community tank. Well oxygenated, fast-flowing, somewhat cool
(24-25 C) water will be needed.>
If you know any clubs in Minneapolis I'd appreciate a contact info.
I'm still new to the city and only know of World of Fish store (may
be you know of them - largest in the city) and Aqualand (also a
reputable store, bought my Ropefish there and got a deal on 10 gallon
tank for crustaceans) - but not of any clubs!
<Well, the one I'm visiting is the Minnesota Aquarium Society in
Roseville, MN, apparently not far from Minneapolis.
http://www.aquarium.mn/
There may well be others.>
Thanks - Elena
<Cheers, Neale.>
Water
Movement 10/30/08 Hello Crew, <Hey -
Mike here today, having (mostly) recovered from Hurricane Ike>
Certainly hope things are going well for you there. <Getting
there...> Starting to get a little cold here in Florida which is a
good break from all the 90+ degree days. <It's nice and cool
here, too - finally!> I am setting up a 75 gallon fw tank and have
been debating over what kind of filter to use. I just found out my
neighbor has 2 almost new hagen Aquaclear 110 filters that he
doesn't plan on using, and he is giving them to me for nothing, so
I am going to go with both of those on the tank. However, I am using a
sand bottom with no live plants and I know vertical water flow is
necessary to bring the detritus off the bottom to get in the water
column. Please tell me what you would recommend for this. I need
something that will move the detritus but not stir up the sand. Also,
do you know of any type of sponge pre-filter that would fit over the
intakes of the AquaClear filters to keep sand from getting into those.
Thank you for your help and all you do, and have a blessed day! <The
110's should provide plenty of water movement and filtration, and
should be all you'll need (as long as they have their ceramic
bio-media). Small overflow sponge pre-filters should work as intake
screens, and are available off the web. Good luck with your new tank!
Setting up a 175 this weekend...new baby Mappa puffer :)> James Hall
<M. Maddox>
Questions (water circulation), FW 10/23/08
Hello, hope your day has been going well so far!
<Tis, thank you.>
Before I ask my question I want you to know that I truly did try to
find the answer on your website. If it was there I missed it and sorry.
I am going to have a 75 gallon fw fish only tank with no live plants. I
will be using power filters and no canister so I know I will need water
circulation. Please tell me if utilizing 2 powerheads are a good
choice, and if so, what output size and where the best placement would
be.
<The power filter alone will provide the flow you need assuming it
turns the tank over at least 4-5 times an hour.>
Thank you for all your help.
James
<Welcome, Scott V.>
Re: Questions (water
circulation) 10/23/08
Thank you. I will be using sand as a substrate. So the filter should
provide enough circulation to remove the detritus from the bottom and
put it into the water for removal?
<That's certainly the theory. The more circulation, the less
likely dirt will collect on the sand. If you keep one corner of sand
"lower" than the rest, the dirt will collect there, and it is
the easiest thing in the world to use a turkey baster to pipette out
the dirt when it becomes annoying. Dirt sinks into gravel, but it
floats on top of sand, so while sand may LOOK like it gets dirtier
faster, it's actually much cleaner because the dirt isn't
hidden away in the gravel. I find maintaining tanks with sandy
substrates really easy, and all my tanks have them. Gravel is SO
twentieth century fishkeeping!>
Thanks again.
<Cheers, Neale.>
Surface splash vs. water movement
2/6/08 Neale, I hope you get this one. You've been so
helpful to me and so many others. I'll try to make it as
short as possible. <Hello again Mitzi!> I'm putting my
Oscar (and a young common Plec) into an 8' long 250 gal tank
and am crossed-eyed reading about filtering options and surface
agitation. I still haven't found a definitive answer.
I've always used HOB filters and don't want to mess with
sumps or drilling. <Indeed.> The important question I have
is this....do I need actual surface agitation if I've got
more than adequate *water turnover*? <The latter is more
important than the former, though more specifically what you want
(especially with catfish) is a filter that effectively draws
water from the bottom of the tank and sloshes it out at the top
of the tank. In other words, circulation. If the filter inlet is
only halfway down the depth of the tank (as is often the case
with smaller filters) then the bottom layer of water might hardly
move at all. Thing of the surface area at the top as the
"lungs" and the water in the tank as the
"blood"; the job of the filter pump is to be the
"heart", pulling all the water through the top if the
tank periodically so it can be re-vitalised with more oxygen and
get rid of any CO2.. I'm going to use external canister
filters (pond filters maybe) that will give me 10-13 times the
turnover rate per hour with no airstones. <Should be ample,
especially if the inlet and outlet are pipes are placed
strategically around the tank to maximise circulation.> Do I
need something that actually splashes the water's surface
like a hang on back filter does? <The splashing is a nice
thing to have because it "folds" the surface area,
effectively increasing it (to go back to our pulmonary metaphor,
rather like the alveoli in your lungs). But is it essential?
No.> Or is water movement equivalent to surface agitation?
<Water movement, provided it is circulating the water in the
whole tank, is better.> Thank you so much for your time.
Sometimes the simplest things aren't quite so simple when you
think too hard about them. Mitzi <Ah, but sometimes if you
think about them in simple terms, they become simple again. Water
circulation, like filtration, can be made overly complicated when
you worry about whether this system or that system is better.
When you actually come right down to it, the basic principle is
very simple, and so is the solution. Cheers, Neale.>
Re: Surface splash vs. water
movement 2/6/08 That makes me feel better about
the whole thing. My goal was to have no dead spots. I want to put
two 900 gph pumps attached to canister filters at the ends plus a
couple magnetic 1050 gph powerheads. If I can just use U-shaped
return hoses hung every 2 feet on the back of the tank, I can put
the ends of the hoses at the top of the water level. It'll
move the water a little when it goes it but it won't be a big
splash like the HOB filters. The LFS owner said to use powerheads
that shoot air into the water, but I want my powerheads towards
the bottom (like your idea) so it pushes the bottom water towards
the filters. The LFS said "just drill it and use a
sump" but I don't want to mess with plumbing and
don't want to have the tank drilled. I just wanted it to be
as simple as possible. Do you think it will work the way I want
to do it? <Probably.> I'm in his tank every day
vacuuming his sand, it drives me nuts having "fish poo"
on the bottom. I'm hoping lots of water movement will shove
it all right into the canister filter :-) The LFS said it's
"over-filtering" for 2 fish but I don't think
that's possible with an Oscar and a Plec. <Indeed.> I
just don't want the fish to be shoved around the tank. Do you
think it'll be too much water movement? <The Plec will
certainly be fine, since they're adapted to rivers, and can
suck themselves onto things if they feel overwhelmed. Many of the
Loricariidae (though not the common Plecs) are rheophilic in the
wild, i.e., they actually prefer rapids over other parts of the
river. As for the Oscar, this depends on the fish and how
turbulent the water is. What Oscars don't want to is lots of
churning water. But a good steady flow, with perhaps one or two
gentle spots behind big rocks or bits of wood, should be fine. I
wouldn't go over 8 or 10 times the volume of the tank in
turnover though, at least, not initially. It takes a while for
fish to get themselves used to stronger water current if
they've been in sluggish water beforehand.> Thank you!
Mitzi <Cheers, Neale.>
Re: Surface splash vs. water movement
-02/06/08 Thanks, Neale. I may start out with slower pumps
and see how it goes. He's got an 850 gph and 4 Emperor 400
Bio-wheels on his 6' tank now and does fine with them. Plays
in the powerhead all the time like Loaches do-hilarious. Thank
you for answering the "splash vs. water movement'
question for me! That was my main concern. Mitzi <Cool. Good
luck with the home improvements! Neale.>
|
Overflows and return pumps, FW...
8/8/07 Hello Crew! <Danny> I have an 86 gallon FW heavily
planted tank with a 20 gallon sump (still under construction, the sump
not the tank), and an external, HOB overflow box. I am using an Eheim
1261 return pump with 3/4'' plumbing to the tank, and I
mistakenly used 1" drain plumbing from the overflow to the sump.
The pump, needless to say, overwhelms my overflow. To rectify this, I
was thinking of adding a ball valve to the return to throttle back the
return pump. <Mmm, perhaps better to divert this excess flow back
to/through the sump... via a Tee and a valve...> But, I want to
upgrade the drain. Should I go with 1-1/4" drain or 1-1/2"
drain? <The bigger the better... for flow, as well as noise
reduction. But... better still would/will be to add yet another
overflow box if going that route> I don't really want to
throttle back the pump, if I don't have to. I want to avoid
overrunning the overflow at all costs. The overflow has a 1-1/4"
bulkhead, but it also has a 1" pipe for holding the pre-filter. It
seems that no matter what size drain I use, the 1" pipe is going
to be my bottle neck. <Yes> I have heard of drilling holes in the
1" pipe to alleviate the bottleneck there, but I think it will
introduce a lot of noise. Any suggestions? Is there any downside to
restricting the return pump (aside from the obvious loss of gph?)?
Thanks, Danny <Please read here:
http://www.wetwebmedia.com/marsetupindex2.htm the yellow tray... re
plumbing... The same input applies here to all tank types. Cheers, Bob
Fenner>
Question about sand and filter impellers --
06/11/07 Hello everyone, <Hello.> I have a question about
sand's effect on hang-on filters. I added some extremely, extremely
fine sand to my tank (it's by Zoo-Med, called
"Repti-sand"). It's made of quartz and is very, very fine
and light, so much that it took about 2 days until the water was clear
after I added it to the existing tank. Really, it's more like dust
than sand. Anyway, I have four emerald Cory's in there now, and
they love scooting around in it and it's very soft so it's easy
on their bodies. It also hasn't affected my pH. I've had it
like that for about a week and a half, and then last night the filter
started making some grinding noises, so I pulled it out, rinsed it out
(some sand came out) and tried to get it to work a few times. Then I
looked online and read about impellers, and I saw that the impeller was
broken (its blades go around and around). Do you think it's the
sand that caused it, or my jiggling it around and taking it apart a few
times trying to get it to work, perhaps not being gentle enough, that
did it? That one was a Penguin Bio-wheel, and I got a new one today, an
Aqua Clear with the different style of filtration. This one's
making kind of a gritty noise as well, and I'm afraid it will
break, too. Is this a common problem? Do you think I should get rid of
the sand, or at least get some heavier sand that isn't so easily
disturbed and sucked up into the filter? I do want to keep some sort of
sand because I want to get Kuhli loaches later on. <Sand can damage
the impellers of pumps. It isn't common though. I use silica sand
in all my aquaria, and while sand sometimes gets stuck inside the
filter canister, it doesn't seem to do any harm. But your own
mileage may vary! Silica sand in particular is quite heavy and settles
very quickly. The only time it gets into the water column (and thus
into the filter) is when a big catfish decides to swish into the sand
and dig herself a burrow. Small things, like Corydoras, simply
don't push the sand far enough off the substrate to cause problems.
Now, if sand gets inside the impeller, it can quite possibly cause some
rattling noise. In the long term, anything that clogs filter media
forces the impeller to work harder, and puts all its components under
more stress. You probably want to make sure the filter inlet is far
enough above the substrate that the fish can't swoosh the sand into
the filter. Adding a decent pre-filter layer to your filter system
(such as filter floss) is also a good idea. My gut feeling is that
while silica sand has been used for many years by many aquarists
without problems, finer sands like your Repti-sand might be just a bit
too fine for safe use.> Thanks for any and all help you can offer! I
really appreciate it! Allison Evans <Hope this helps. I'm a BIG
fan of sand in aquaria, and agree with you that loaches and catfish
really benefit from its use. But it does need to be handled properly.
Cheers, Neale>
pH and water flow 5/17/07 Crew, <<Hi,
Erik. Tom with you.>> Great site, thank-you. <<Thanks,
Erik. Glad to hear we've been helpful so far.>> I have a 30
gallon tank with Eco-Complete as substrate and nothing else in it. I
use RO/DI water. My Pinpoint pH monitor reads the pH as 7.2 and up with
the Whisper 40 running (only has carbon in it) and reads 6.75 and lower
with the filter off and not flowing at all. Why? <<Well, now both
of us have an issue to deal with. Your issue is that pH monitors
don't work well in purified (RO/DI) water. Mine is trying to
explain, in simple (?) terms, why they don't. First, and not
surprisingly, RO/DI water has very little in the way of buffering
capacity which means that pH can change quite readily, up or down.
Simple enough. Second, commonly our pH is affected by the absorption of
CO2 from the atmosphere. This is why you can expect pH to typically
decrease over time since dissolved CO2 in the tank lowers pH. How
quickly this takes place depends on a wide number of factors but, once
again, this can depend, in part, on the buffering capacity of the
water. In our homes, CO2 levels can be, and typically are, higher than
outdoors yielding a higher concentration of the compound in the air
and, therefore, greater opportunity for our tanks to absorb it. (RO/DI
water generally runs in the pH range of about 5-7 depending
substantially on the level of dissolved CO2.) Third, CO2 is
'driven' out of the water by agitation such as what you might
create with airstones, UGF's, HOB filters, etc. Though this
doesn't even scratch the surface of a highly complex topic, I
believe that what you're seeing is the absorption/dissolution of
CO2 in your tank caused by calm periods (filter off) resulting in
increased CO2 absorption (lower pH) followed by active periods (filter
on) resulting in decreased CO2 (higher pH).>> Also, the readings
on the pinpoint monitor fluctuate a tenth of a point constantly, it is
never pegged. I know constant pH is better than a specific reading and
I can't get the pH to stay at one reading even in this small tank.
<<The greater the precision of the instrument, the more likely it
will be to show variances, Erik. You might think of it like the
'refresh rate' of your computer monitor. The higher the refresh
rate, the more screen 'flicker' you'll observe. Your
Pinpoint monitor is constantly refreshing its readings. In conjunction
with what I've already discussed, I'd be very surprised if it
weren't constantly fluctuating. A very nice piece of gear but it
has drawbacks in this particular set of circumstances.>>
Respectfully, Erik <<Hopefully this will shed a little light on
your situation, Erik. Best regards. Tom>>
Automatic leak detector/ water valve shutoff
system? 5/2/06 Hi,
I have a FW African 120G plexi tank that
is plumbed through the bottom through a double size Lifegard set (UV,
mech, chem, and heater modules) then back up through spray bar towers
in the corners, the tank is visible on three sides so it was important
for me to have as little filtration/equipment in the way as possible. I
have three drains that T into one 1" pvc line, and the strainers
are only perhaps 1.5 inches above the sand. Looks great, works great,
but what if there is a leak!?!? <... water on the floor, possibly
drained down to their level> It has been up over 6 months or so and
have had little trouble, but it is always in the back of my mind.
Ideally I would rig a leak detector up to a relay that upon detection
of leak, it closes the in/out ball valves and turns off the UV and
pump. <There are such alarm devices on the market>
I have the leak detector circuit
and am fairly competent on wiring all the relays, but what is holding
me back are the solenoid valves. <Where would you install these that
would help?> I thought that I would be able to use a sprinkler valve
as they are cheap and pvc, but to throw the ol monkey wrench in my
plans, it has to have a minimum of 15psi to operate correctly. I am
running 3-5 tops. Does anyone know of a different type of valve that
would fit the bill? <None that I would use> I know I can put a
check valve on the return line, which I should have done in the first
place, but I still would like at least one that would close the system
down if I were to spring a leak. In the
meantime I have plans to raise the drains up so if it does happen, at
least my fish may have enough water to survive the event, and also I
think I may drill a drain through the floor (under the tank in the
cabinet) as to not flood my room. Any advice? thanks! <Mmm, I would
not worry here. The likelihood of a disaster is likely very small...
Next time/tank, either drill through the back or run the (return) lines
over the top, the drains through the tower/s. Bob Fenner>
Too much filtering or water movement How much is too much? -
20/1/05 I was wondering what would be considered too much water
movement. I have a 75 gallon tank and one Fluval 405. I wanted to put
in a second Fluval 405 to make sure the tank stays nice and clean. But
then I was worried about the problem of too much water movement. Right
now the fish in the tank don't seem to have any problems with the
one filter. What do you think? <Depends on the fish (and, more
importantly, corals. However, in general, fish can withstand - and
sometimes prefer - far higher currents than we provide. Ever swum in
the ocean? Or a fast flowing river? If I am right in thinking that a
405 provides a max. flow of around 350gph, then two such filters would
be perfectly suited for freshwater.... I would be looking for more flow
for most marine tanks. Best regards, John> Rusty