I recently got my water tested and the pH was 6.2 in my 90 gallon tank. The reason being was because I have well water and the pH of it is 6.0 (maybe less!) I can't keep fish in this kind of water! Everytime I do a water change my fish will probably get pH shock and end up getting diseases and being unhappy. What can I do to fix this problem? If I add crushed coral to my filters won't it make it go to high and buffer it too much? I want to get the pH around 6.7. I added this sandstone decoration rock to it but I don't know if I should keep it in there because it might raise the ph too high. I had a pH test kit but I lost the vial that goes with it . I think I'm going to buy a master's test kit soon. So anyway, what should I do to fix the problem?