I Have Ph 6 What Can I Do To Increase It To 7?

[fluttermoth]

Don't automatically assume that any fish deaths you experience now are due to the low pH, if they went through a cycle; that can have long term effects on the fish and cause them to die, even if the cycling's done now.

 

[4seasons]

here are my test results:
GH-0
KH-40
PH-6
Nitrite- 0
Nitrate - looks like from 0 to 20 the color looks like something between the ones listed for 0 and 20

I live in near a big city that is why I presume the water is relatively "soft". The past 2 tests i have conducted have showed Nitrite 0 so I presume my tank is done cycling. If you guys suggest that I let it be then so be it, but if fish start dying on me I will have no other choice but to find a way to increase the PH because that would be the only logical explanation. One of my swordtails is showing symptoms of near death already, it is barely moving much like the swordtail male that died a week ago on me but that was due to my tank not cycled

Those test results look very close to what I tested our rain water at. Just to echo what others have said, look at keeping soft water fish and stay away from live bearers that like hard water.