FAQs on Freshwater Aquarium Wet-Dry
Filtration
Related Articles: Freshwater Filtration, Know Your Filter Media, A
Concise Guide to Your Options by Neale Monks,
Power Filter Impressions,
A review of some popular mechanical filtration systems
by Steven Pro, Canister
Filters By Steven Pro, Setting
up a Freshwater Aquarium, Tips
for Beginners,
Related FAQs: FW Filtration 1, Biological Filtration, Establishing Cycling, FW Sponge Filters, FW Canister Filters, FW Hang-on Filters, Ultraviolet Sterilizers, Chemical Filtrants,
Diatom
Filtration,
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Trickle filter pads 8/27/11
Hi Wet Web Crew
I first wanted to thank you for your support and help for my
previous
questions.
<You're welcome.>
After doing a lot of searching on your site I still have not been able
to find an answer to a question I had.
Anyway, I have a 300 gallon African cichlid tank with a 80 gallon wet
dry sump that has two 2" drains emptying into a filter pad before
it trickles into the bioballs. I am planning on having 1500
gallons/hour flow rate into the filter. I have read on your site that
Emperor Aquatics gravity felt filter bags are very effective at
removing solid waste.
<Can be. But really, anything that incoming water flows through will
filter out faeces and detritus. The question is how easy it is to
remove and rinse such media.>
Would it work to attach one Emperor Aquatics gravity felt filter bag to
each bulkhead draining into the wet dry sump and having the bags lying
horizontal on top of a finer mesh size filter pad?
<If ahead of the biological and chemical media, then yes.>
Could I remove the filter pad below and just use the Emperor bags
instead?
I know I will need to remove these bags daily and replace with clean
ones. I believe the filter bags operate most efficiently in a vertical
position but wanted to know if my idea would work with them positioned
horizontally on the trickle plate and with or without a filter pad
below.
<Obviously you need to maximize the surface area of media reached by
the water. So a horizontal pad will generally work better than a
vertically-aligned thing, only because the horizontal pad
"meets" more incoming water. You do need to make sure any
mechanical media is BEFORE any biological or chemical media.>
I also had a question concerning using two smaller Iwaki return pumps
to get a 1500gallons/hour flow rate for redundancy purposes or to just
use one large Iwaki pump and have another large Iwaki pump for
backup.
Thanks again for your time and assistance and have a great weekend!
Steve
<Cheers, Neale.>
AGA MegaFlow Sump Model 3: Wet dry filter with
Bioballs & Ceramic Stars- Anaerobic vs. Aerobic
Products 5/5/10
Hello WWM crew! I finally have a question that has not already been
asked and answered. Your website has been such a great resource since
establishing my aquarium(s) a few years ago.
<Good to know.>
Today, my question pertains to my drilled 110 mixed African
Cichlid aquarium. There is a minimal amount of crushed coral
as substrate, and copious amounts of rock work, both natural and
plastic injection molding.
I will spare you the inhabitants, as I do not believe it is
contributing to my problem, although I will mention that my tank is not
considered "overstocked". I have an AGA MegaFlow Sump Model
3. In the sump, I use a return pump rated at 1000 gallons per hour, but
once the water is lifted to the 5 foot return height, is pushes closer
to 750 gallons per hour. After research, I have learned that the
MegaFlow 3 sump can handle about 600 gallons per hour, so I use a ball
valve to reduce the flow to very close to the 600 gallons per hour
figure. If you attempt to push any more water through this sump, it
clearly lets you know that you are exceeding the limits by operating
with a loud gargling sound and the water levels do not remain
level.
<OK.>
About 12 months ago, I mentioned to my LFS that I was having a problem
with my Nitrate's constantly being above 40 ppm.
<Too high for cichlids, as you know.>
According to the publications I have read, nitrate removal is directly
proportional to the amount of water removed (assuming the replacement
water has 0 ppm nitrate).
<"Removal" isn't the word I'd use; more
"dilution". If you have 40 mg/l nitrate, and then do a 50%
water change with 0 mg/l nitrate water, you get 20 mg/l nitrate
overall. While nitrate removal is possible in freshwater aquaria,
it's rarely cost effective. Fast-growing plants are perhaps the
only practical approach.>
Even after a 50% water change, I would notice that my nitrate would
reduce, but not by the amount the formula would dictate.
<Meaning? I assume you mean as explained above? Do bear in mind
nitrate test kits may not be especially accurate. You can take it as
read that if you dilute the aquarium 50% with nitrate-free water, then
the nitrate level will drop by 50%.>
I checked my public water, 0 ppm of nitrite and 0 ppm of nitrate. After
a period of 5-7 days, my nitrates would spike back to above 100
ppm.
<I see. But does the nitrate level go down *immediately* after water
changes?>
My LFS offered a few options. First, they recommended the use of
SeaChem's Purigen, which I have been using for 12 months, having
recharged the Purigen twice.
<Expensive, and generally overwhelmed by cichlids. Chemical removal
of nitrate is only cost effective in situations where nitrate is
carefully limited already, e.g., in reef tanks. In busy freshwater
tanks, you're
dumping far more protein into the system, and there's far less
natural denitrification -- i.e., live rock, DSB -- going on as
well.>
They also suggested that mature bioballs can become "Nitrate
factories", but I have read the comments on WWM that disagree with
this statement.
<Indeed. It's complex. Some authors have argued that biological
filters, particularly canister filters, become "nitrate
factories" because the ecology of the bacteria inside them somehow
generates higher levels of
nitrate than expected. Personally, I'm skeptical of this because it
doesn't make much sense biologically, and I'll make the point
here that I actually do have a BSc and a PhD, so I'm not
speculating out of nothingness. Nitrogen is needed to make nitrate, and
the source of that nitrogen is fish food via livestock. Nitrogen
fixation from the atmosphere, as happens in the wild, isn't
happening in aquaria at any appreciable rate, except perhaps among
blue-green algae. So, provided a biological filter is cleaned and
maintained properly, there's no possible way it could magically
generate nitrate above and beyond the supply of nitrogen via fish
wastes. In other words, if you add 5 grammes of nitrogen per day,
you'll get 5 grammes worth of nitrate, whether you're using a
canister filter, a sponge filter, or an undergravel filter. Cleaning is
important because some detritus takes a long time to break down, so in
theory you could have, for example, dead leaves in the filter that over
several months eventually break down and add more nitrogen to the
system, but if you let your filter get that dirty anyway, you'll
have other problems as well because of the reduced flow rate!>
They recommended changing bioballs for ceramic stars, as used in
canister filters.
<Won't make the least difference.>
I took the suggestion, and bought two small packs of ceramic stars and
replaced an equivalent number of bioballs. I would estimate that my wet
dry is now filled with approximately 85% bioballs and 15% ceramic
stars.
Here in lies my question:
After additional research, I learned that ceramic stars are used in a
canister filter because of their supremely porous nature providing a
tremendous amount of surface area for bacteria to grow (in anaerobic
reactions).
<In theory that is the case, but in practice virtually all the
filtration inside canister filters is aerobic. To get anaerobic,
nitrate-reducing filtration, you need extremely slow flow rates, hence
the need for things like DSBs and live rock.>
I have also learned that the bioballs are the surface for bacterial
colonies that will be acting in aerobic fashion in my sump. Can using
ceramic stars (if they are designed for anaerobic bacterial colonies)
in an
aerobic setting cause nitrate spikes?
<Can't see why.>
How else can I remedy the situation? Diatom?
<Nope.>
Fortunately, I monitor the tank closely for the inhabitants sake. I
feel that if I cannot get the nitrate's down to at least a
reasonable level, I will begin to notice the long term affects on my
fish, and I really do not want to contribute to their stress, declining
health, or eventual death<I'd look at other factors. Filter
maintenance may well be an issue, but otherwise concentrate on reducing
the nitrate going into the system via water changes, and on reducing
the nitrogen going into the system through limiting food supply and
stocking density. If you're keeping Tanganyikans and some
Malawians, plants can also make a big difference; under bright light
fast-growing species such as Vallisneria will be using up considerable
amounts of nitrate. A freshwater DSB may also be an option;
see the recent issue of 'Conscientious Aquarist' elsewhere on
this site for more.>
Thank you so much in advance for any assistance that you can offer. I
am happy to try solutions to remedy the situation.
Regards,
Jeff S.
<Cheers, Neale.>
FW wet dry... New World Cichlid
filtr. 2/9/10
Hello there,
<Hello,>
I am in the process of setting up a 135 gallon fw tank. I have a fairly
large Oscar, a jack Dempsey, and a large Pleco. I am planning on
getting them a few more tankmates once the tank is up and running. I am
also planning on having plenty of live plants throughout the tank. I
have some aggregate gravel as my substrate. I am building a wet/dry
filter and just had a few questions. I am setting it up very similar to
the Eshopps 150-cs, but I was curious as what I should use for
mechanical filtration. A few of the sources I have read on the internet
say polyfill is the best, but I wanted to check with you guys before I
made a purchase. Any suggestions would be very much appreciated. Thank
you very much for your time.
Cheers!
Blake
<Yes, a wet/dry filter will work. However, the reason they're
rarely used in freshwater tanks is that they drive off carbon dioxide,
and that makes it difficult for plants to grow. Floating plants will be
fine though, since they get their CO2 from the air, and given Oscars
and JDs uproot plants anyway, that's likely the way you'd have
to go. In terms of mechanical filtration, it really doesn't matter
what you use. There's no "best" really with mechanical
filter media, since anything fine enough to trap silt will do.
Mechanical filters are let down by how often *you clean them*,
since
they're only as good as the last time they were rinsed off; leave
them clogged up with silt for a couple of weeks, and they won't do
anything at all. So choose something easy to clean and (if necessary)
cheap to replace.
Cheers, Neale.>
Re: FW wet dry
If that is the case then what would be a more appropriate method of
filtration?
<Well, depends what you're after. Since Oscars and JDs dig, and
Plecs can be pretty hard on small plants, your best bets in terms of
plants for the bottom of the tank will be Anubias, Java fern, and if
you can get it, Bolbitis. All three are slow-growing, so have little
impact on water quality or algae control, but they are pretty and
difficult for fish to destroy (Java fern in particular seems to taste
horrid, so most fish ignore it). Most critically, they are grown
attached to rocks and bogwood, so won't be bothered if your
cichlids dig up the sand or gravel. If they get moved about, that
won't bother them either; just put 'em back where you want
them, or move the plants around so your fish have territories. Throw
some floating plants into the tank for algae control, and you're
all set.
Anyway, if you grow these, you're able to use a reverse-flow
undergravel filter, which is perhaps the best all-around filter for
large fish. Unlike other filters, these have water pushing UP through
the gravel, and this moves faeces and detritus into the water current,
and then the canister filter can remove them easily. So you get good
water quality PLUS good water clarity, without having to constantly
clean the gravel. Having said this, because cichlids dig, they can
"short circuit" undergravel filters of all types, so you will
need to place a gravel tidy under the top half inch or so of gravel, so
that the cichlids can do minimal damage to the filter bed. If this
doesn't appeal, and you really do want live plants, then the best
filters are those that "splash" the water the least, since
the splashing is what causes the CO2 to be thrown out. Plants with
roots hate undergravel filters, so that's another issue too.
Regular canisters are perhaps the best, since these can be rigged with
spray bars just under the waterline, so they ripple the outgoing water
rather gently. The downside of course is that the less circulation of
the water there is, the happier the plants will be, but that's the
reverse of what big cichlids want. It's perhaps best to think about
what sort of aquarium you want: an underwater garden, or a community of
cichlids with just a few plants as a backdrop.
There are some cichlids that love plants, including (surprisingly to
some) quite a few Malawian and Tanganyikan species that live in the
vegetated parts of these lakes, often around beds of Vallisneria. Since
Vallisneria is remarkably easy to grow, and comes in a variety of
colours and sizes, that can be a nice way to combine cichlids, plants,
and a few catfish.
Cheers, Neale.>
Wet Dry filter media for cichlid set
up 11/25/09
Greetings Crew, may I ask you a question in regard to biological
filtration?
<Sure>
I am planning an African cichlid setup. The display tank will be a 125
gallon with a 40 gallon sump. I am leaning toward a DIY wet/dry filter
in the sump. Could you please suggest the best media to utilize in a
wet/dry application and how much I would need for proper biological
filtration?
<For such a set up, a good deal of carbonaceous rock and a deep sand
bed of finer sand (4-5 inches of nominal 1/16" diameter) will be
best here. All submersed, that is no plastic media necessary>
I have looked at bio balls and have loosely figured on five gallons. I
am also hearing that better bio media is available now a days. Any help
is very welcome. Thank you Mark
<It is... Please read here:
http://wetwebmedia.com/bioballfaq2.htm
and the linked files above. Though this section deals with marine
systems, the principles are the same for freshwater.
Bob Fenner>
Freshwater sumps 11/28/2007 Hello again. You
have been very helpful so far and I feel bad about pestering you for
info but again there seems to be a lack of info on this subject. I am
converting from marine to freshwater (most people go the other way) and
have a sump which I want to use with this system. The tank is about
500ltrs with a 100 ltr sump. My question (to finally get to the point)
is what would you recommend to put in the sump. Currently the first
section is bio balls, then miracle mud with colerpera (sorry about the
spelling) and finally live rock with a live sand bed. I know the live
sand will 'die' and the live rock would be a waste. I was
thinking about keeping the bio balls but replacing the mud with gravel
and some sort of plants. The main section was to be changes to gravel.
Have you any suggestions with what I am proposing. Any help gratefully
received. Many thanks Paul. <Hello Paul. Unless you're keeping a
hard water aquarium for, say, Tanganyikan cichlids then don't leave
anything calcareous in the sump. For a standard community tank or
similar, then opting for biological filter media of some type is
probably the way forward. More bio-balls or some sponges would work
well. Because nitrate control in freshwater systems is both easier
(plants, water changes) than in marine tanks and less critical
(freshwater fish largely nitrate-tolerant) there's no real need to
provide denitrification in a freshwater tank. But some people have very
effectively used 'vegetable filters' and 'algal
scrubbers' as part of the filtration system, by placing
fast-growing plants/algae into a brightly-illuminated chamber.
There's a book called "Dynamic Aquaria" that discusses
these, among other such esoteric topics. While hardly a book for the
casual aquarist, it's an interesting read if your library has a
copy. Basically the idea is that you optimise plant/algal growth, and
then crop the plants (even daily!) effectively removing wastes in
"solid form". Some freshwater plants, such as Cabomba and
various floating plants, will grow incredibly rapidly if provided
optimal conditions. I hope this helps, Neale.>
Bio ball alternatives in freshwater --
05/08/07 Hi team, <Greetings!> I would like to know of any
ideas for my wet/dry driven 125g planted loach tank. I have read lots
of ideas on the salty side of things, but don't know if these ideas
would translate into freshwater. <Essentially similar to marine
aquaria except you don't have the option of living rock. Standard
protein skimmers are only viable in brackish water tanks at SG 1.010
upwards. There have been freshwater skimmers invented from time to
time, but as far as I know none have become inexpensive commercial
products.> Right now I have 6 clowns that are 4-6 inches and 5
boesemanni rainbows and assorted tetras. I am currently running
bioballs and about 4.5 lbs of sintered glass in my sump. Any ideas on
nitrate reduction? <Generally speaking nitrate management in
freshwater tanks is easier and less critical than in marine tanks. With
a few exceptions (such as mollies and Tanganyikan cichlids) freshwater
fish are fine with even fairly high nitrate levels in the 50-100 mg/l
bracket. Why nitrate is easier to manage is that doing large-scale
water changes is easier and less expensive than in a marine tank
because you don't need to add salt. Under most circumstances, one
or two 50% water changes per week will maintain excellent water
quality. Finally, the use of fast-growing plants removes nitrates
quickly. Floating plants and fast-growing stem species like Cabomba,
Vallisneria, and hornwort are recommended for this. Under good lighting
(3 or more full-length fluorescent tubes) these plants will be growing
so rapidly you will cropping them on a weekly basis. In the process of
growth they remove nitrate and suppress algae (in part through
allelopathy).> Thanks, CW <Cheers, Neale>
Wet/Dry filtration in freshwater system
11/16/06 I recently converted my 75 gallon SW to
freshwater. In doing so, I returned my bio-balls to the
Wet/Dry Sump. Is this necessary, or will it add to higher
nitrates, or other problems. If I remove them, should I put
anything in the sump. <Is about as "necessary" and of use
as with/in marine applications... I would remove them again once this
system is firmly establishes> Also, I believe I read
somewhere on the site that live plants are not recommended with a
trickle filter-wet/dry set-up. Is there a way to
successfully keep live plants in my system. Thank You!
<Mmm... should not matter (much) here... though... as many such
truly aquatic plants can/do use ammonia/ium directly as a source of
nitrogen... and the boosted nitrification from the WD too readily
removes this... I would wait on adding much in the way of plants till
after you've removed the plastic media. Bob Fenner>
FW Wet-Dry, Af. Cichlid Sys.... 7/8/06 Hi
<<Hello, Rene. Tom>> I'm getting a 125 gal. tank with a
wet dry filter system. <<New or "pre-owned", Rene?
Information sheets contained with a new system will have the
manufacturer's recommendations for cleaning/maintenance of their
particular filter.>> Currently I have African cichlids. My
question is what is the best maintenance? How often do I have to clean
it? <<I state the obvious here but the "best"
maintenance is that which keeps the mechanical filtration media clean
and free of built up solids along with maintaining a healthy supply of
beneficial bacteria in the bio-media. Some wet-dry filters come with
built-in protein skimmers, which will fairly ineffective for a FW
system. As far as how often to clean it goes, this will be largely
experimental on your part but I would recommend cleaning the
"pre-filter" media on a monthly basis to start. Wash this out
in used aquarium water (optimal) or in tap water that you've
prepared with a dechlorinator (less optimal). The frequency will, of
course, depend on the load your fish place on the filter based on
number of fish, sizes, feeding habits, etc.>> Do I remove all of
the filter media and replace it? <<No. The pre-filter will
ultimately need to be replaced as this will probably break down over
time but the bio-media need never be replaced short of a calamity in
the tank. Depending on the type of filter you're getting, this
bio-media may be plastic, ceramic or some other sort of material and
will house your beneficial bacteria. Replacing it would throw your tank
into a "tailspin" toxin-wise, which is why you should rinse
it - again, in used tank water - and put it right back into service.
Provided you keep your pre-filter in good order, cleaning the bio-media
of built-up solids shouldn't have to be done very often. As
I've mentioned, hopefully you'll have access to the
manufacturer's recommendations. Eheim, for example, makes a wet-dry
filter system wherein the foam pre-filter should be discarded after
about a couple of months. The mechanical and biological filtration is
left to the other media contained in the canister after this
time.>> Any suggestions will be much appreciated. Rene
<<Hope I've given you enough to go on, Rene. Enjoy your new
set-up! Tom>>