What do fish think about?
Join Date: Dec 2010
Location: East Bremerton, Washington
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Re: pH keeps dropping
As stated above, carbonate hardness (KH) and pH have a direct relationship, and this is dependent on the CO2 concentration in your tank. KH is a pH "buffer", so to speak, because a higher KH will prevent pH swings due to dropping and rising CO2 concentrations.
Your plants consume CO2 and produce O2 in the daytime, and at night they do the opposite. This results in a gradual shift in pH throughout the day as CO2 concentrations that have built up in the tank overnight are depleted by photosynthesis. The lower your KH, the more drastic the pH swing will be.
There are methods to boosting KH, some of which I remember vaguely (like a bag of crushed coral substrate), which will solve your pH problems. DO NOT USE PHOSPHATE pH BUFFERS! They are harmful to plants, and do not fix the problem.
Hope this helps!
Note: Fish can tolerate a wide range of pH's, so long as they stay constant. Once you boost your KH, your pH should even out. After that, leave it alone.
ClearForLife 10G Acrylic, 6 HET rasboras, ~80 RCS, 3 otos, various snails. Ludwigia repens, various moss. Eheim 2211 Canister, 50W heater, Finnex FugeRay Planted+ 17W LED.
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