High Ph?

[bjmagik]

Hi there people,
Can you tell me why the ph in my tank keeps rising to a high alkaline. I keep lowering it and within the next day it is high again. I have just cleaned the whole tank out due to a infestation of some type of worm in the gravel and now have this problem since the change. Why does the ph keep increasing and what can i do to stop it as my fish are going to get sick i'm sure. I kept half the water from the old tank when i changed over the tank.

 

[rdd1952]

What did you use to clean the tank and did you add anything new (decorations, substrate, etc.) after you set it back up?
Are you using any chemicals you hadn't previously used?
What is your tap pH, tank pH now and before?

For now, you should stop trying to lower it. A high, stable pH is much better for the fish than one that is constantly going up and down.