How To Lower Ph?

[OldMan47]

If you are changing your water frequently try a little less water change. The nitrates in the water are actually present in the form of a weak acid and will cause the pH to drop a little. This is usually viewed as a problem of having too much nitrate during a fishless cycle but the effect of the acid doesn't change just because there are fish in the tank. I would watch closely and keep the nitrates below 40 ppm but minimize the amount of change and operate closer to the limit to drop pH if its really all that high. This will affect the pH more than playing with the fish's oxygen supply.
I have not yet seen what pH you are trying to lower or why you think its too high. What low pH fish do you have or what extremely high pH do you have? My own experience with pH is that its best left alone if the water out of your tap is in a pH range that people can drink it without harm.

 

[ALEXF]

Well my ph is about 7.6 and i wanted to lower it to about 7.0 Just to give all of the fish i have a balanced amount. But Ill try that.

 

[OldMan47]

Alex, I have tap water that runs about 7.6 with a hardness of about 12 degrees GH and KH. I also have a 120 gallon community tank that has livebearers (high pH) and rasboras, angels, barbs (low pH). All of my fish are very happy and healthy and are living for years with no pH manipulations. Even the mollies that supposedly need salt are doing fine in pure fresh water. I would lean toward leaving well enough alone if I were you.

 

[ALEXF]

OK Thanks, I just want the best for my fish, and i dont want to tramatize them at the same time. Ill leave it alone. I mean i have had my angel for about 5 months and it sems totally fine. So yea ill just leave it be.