Had the same problem. I have hard water in the house which holds the ph high for a long time. My fix to the problem was a water softner pillow and drift wood from a fish store.
Make sure you don't have shells or any stones that might raise your ph. You should read up on kh, gh, and ph and how...
I love the store in Park Ridge. Animal kingdom was always my childhood favorite. But here's on more you should definatley check out. My current favorite.
State IL but also locations in OH and in NY
SW corner of Golf and Roselle Rd.
Hoffman Estates IL
website:
LINK TO AQUARIUM ADVENTURE IN IL...
In simple terms the top tank cannot drain water out without filling with something in the space of the water. If there was a hole at the top it would fill with air. What I'm trying to figure out is the air pump thats in there. The air must gather at the top of that tank and slowly empty the top...