i have 2 jacks and a severm. my problem is that any new additions i make die within a day. and i dont know why. all readings seem normal. ph is a 6 and i make water changes 2x a week. i dont want to keep buying fish if they gonna die in a matter of hours. i must of already bought like $100 of fish and have them all died. even my severm was not doing good but he came back and now is healthy also my jacks are active and healthy also. ive tried a red devil, bunch of rainbows, large tetras, and barbs. i need help please. i want to add to my tank. i have a ugf with 2power heads, eclipse setup with biowheel, fluval, and a fluval canister with a uv sterilizer hooked up to it. i also have a bubble wand in the back to increase oxygen. any ideas???