Ph problems please help

So i posted a couple picks last week and it was mentioned that it was probably a ph problem. so i got a ph test kit for aquariums to test the water 7.8+ and the run off of well below six. what do i do????? I decided to flush the plant with water that i brought to a ph 0f around 6.9 or 7. but the runoff is still highly acidic and hasnt seemed to change yet what can i do to bring up the ph to a normal level??/

You need to flush it through until the water coming out the bottom is the same ph as the water coming out the top. Then you will know that you have gotten all the bad "voodoo" out.

You growing in peat or something?