Tap & tank water pH different

  1. MJDuti

    MJDuti Well Known Member Member

    Let's say I have a buffered Lake Tanganyika cichlid tank (via crush coral/African Cichlid sand, Texas holey Rock, etc) with a pH around 8, but my tap water is 7.4. I've read they don't like much in the sense of water parameter changes. Would doing 20% WCs with the lower pH tap water hurt the fish? Or will there be enough buffering power to prevent a drastic pH swing?
  2. el337

    el337 Fishlore Legend Member

    I think you have enough buffers in there to prevent a ph swing. Do you know your kh?
  3. CindiL

    CindiL Fishlore Legend Member

    That's a small amount, you could easily do up to a 50% water change without harm to them. The rule of thumb is generally to keep your net ph difference of .5 or less so if your tank is 8.0 and your tap is 7.4 and you changed out 50%, that is still only a difference of .3. So in short 20-40% would definitely be safe :)

    What can be just as important is the difference of minerals between tap and tank. Do you know your GH/KH of both? Worth finding out if you don't.