Help with pH please

lisaann4jc

AC Members
Oct 21, 2005
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I'm at the beach and my fish are "Home Alone" with my husband and kids. So far 3 of my fish are dead. I have been treating the tank with salt and increased temp to rid my fish of ick. When I left, all were well except for one. I did a water change and added the salt back gradually. My parameters were pH 6.5 ; alk 0 ; hard 75 ; nitrite 20 ; nitrate 3.0. The parameters before the change were all the same except pH was 6.8 and as of last night, all parameters were the same except pH was 6.2. What should I instruct my daughter to do? The 3 fish died about 1-2 days after the water change which has been 6 days ago. No fish have died since. 2 platys and a zebra danio are the ones that died. What I have left is 2 platys, 3 zebra danios, 3 dwarf gouramis, & a small catfish. :dive:

Oh! Also, while I've been down here, I've found some nice pieces of "rock". It's actually where the hurricains have torn up pieces of roads, driveways, and sidewalks. They have been tossed around a lot and now might make good hiding places and decor for my freshwater aquarium. If I bleach the and boil them, could I put them in my freshwater tank? I know I can't put in any of my coral.
 
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Actually, with such a low alkalinity (KH), adding some of the coral would help buffer the tank and stabilize the pH.

The pH changes won't be lethal to the fish. But they are the result of the really low buffers. I would have your daughter slowly add a bit of baking soda--and get that KH up to 3. That will stabilize the pH, as well as other parameters.
 
i think your fish deaths are the result of toxic nitrite levels and have less to do with your ph. check that nitrite level again (20???) that can't be right .. perhaps you've confused nitrite and nitrate? the numbers would make more sense in that case but would still account for fish deaths.

that said, your ph seems to fluctuate quite significantly .. undoubtedly a result of your extremely low alkalinity. i'd suggest increasing that through the use of crushed coral added to your filter.

i'd not use road rocks in your tank
 
Since there is salt in the tank to combat ich, the salt is also helping with the nitrite toxicity issues. What's the ammonia level?
 
salt at 0.1-0.3 percent, will temporarily mitigate the negative impact of nitrite toxicity. the chloride ion counteracts the nitrogen blockage of oxygen uptake. since you're using salt for parasite treatment, it may be helping with nitrite toxicity as well ... assuming you're using a sufficient concentration.

since you have nitrite present, you may well have ammonia as well ... also toxic to fish. i'd test for it and finding any, you have two options. (a) add a water conditioner such as Amquel® that detoxifies both ammonia and nitrite (a temporary measure) or (b) perform water changes sufficient to dilute both ammonia and nitrite to less than toxic levels. this latter option is a long term solution to your problem in that the filter will eventually cycle and remove any ammonia and nitrite biologically, converting it to nitrate.

you should also explore the reason(s) for having ammonia and nitrite in the first place. filter still cycling? too many fish in a too small tank? dead fish remaining in the tank too long? insufficient water changes? only you can answer these q's.
 
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