KH hardness for a Tetraodon nigriviridis ... GSP    4/8/06 Dear Crew, <Catherine> Hello again, I have a GSP about an inch big in a 120 litre tank. just a quick one ! I have just tested the KH of my puffers water and it is 13dKH which is 232.7ppm KH do you know if this is suitable ? <Yes... as you likely are aware this is a brackish to (with size/age) marine species... and these values are in line with such water> Also, I cant seem to translate oz per gallon into specific gravity, <Ounces of? Salts? For mixing, actually pre-mixing, best to use a "given" volume of both/all... blend, circulate in a dedicated container and store for a week or more before use> apparently I'm aiming for about 3 oz per gallon (imperial), but to get to this I have to go up 1.002 a day but I don't know how much that would be in oz per gallon, math was never a strong point of mine. Thank you Cat <... Mix outside the system... Please see the Brackish subweb on WWM re this species, brackish water preparation: http://wetwebmedia.com/BrackishSubWebIndex/BrackishSubWebIndex.htm Bob Fenner> Going From Brackish To Freshwater  12/10/05 WWM crew, I have a brackish tank which my fish recently died and I want to turn it into a freshwater tank. I was just wondering if I could skip recycling the tank by simply emptying the brackish water and replacing it with freshwater. Hope this question isn't too stupid... thanks. < Brackish is a very loose term that means it is between pure freshwater and pure saltwater. Depending on the exact salinity you were keeping your fish at, after replacing the water, I would still add Bio-Spira from Marineland to cover all the bases.-Chuck>