Originally Posted by Mumma.of.two
Ok that is VERY high. They need to be 20ppm or lower. Doing a water change every 3 weeks isn't enough. You need to be doing at least 50% weekly. for now you need to do multiple large water changes daily until you get the nitrates under control. Don't use distilled water. It doesn't contain any minerals needed for a stable pH, fish and plant health. Your tap water and water conditioner is preferred. Don't mess with the pH at all. Adding chemicals to do this can be deadly. Most fish can adjust to any pH as long as its stable. Fluctuations in pH can kill.
Can I get you to google Old Tank Syndrome?
^^ this is important
A stable tank is key to fish health,big PH or temp swings are not good for your fish, it can cause stress which weakens their immune system. A healthy stress free fish can resist most infections and illness, when they get stressed then you start to see Ich and other infections happen. Some fish do prefer a certain PH but unless you are experienced with keeping PH at a certain level it is best to just leave it alone, your fish will be fine