Ph difference, too much?

[daffyfish]

My tank has been at a ph of 6.5, with a kh of 3.
The water, that I am adding is 8.8!
This is after aging. It has been thru a 3 stage filter, with prime (just in case).
I have never had a ph this high. I don't know what has changed with my water.
Some of my juvies are starting to darken a bit.
Is this too much of a ph drop?
If so, how do I lower it?
Thanks

[Orange Crush]

How often do you do water changes and clean your filters? Do you have substrate? If yes, how often do you clean that?
Has the pH of your source water before aging recently changed?
6.5 ---> 8.8 is dangerous

[daffyfish]

BB tank. 50% WC daily. Clean prefilter, on AC, every 2-3 days.
Haven't checked the ph of the source water, in a while. :(

[mcishaque]

50% daily, and still that much of a delta? Raise the KH of your water: add 1 tbsp of baking soda per 40 gallons of water. Search SD for "baking soda" if you want to read up more on how it might help in your specific situation.