I did a 30% water change yesterday after the nitrAte test of 20. Used ph of 7.6 to refill. PH this am is 7.4. Will not do any changes for 3 days (unless necessary) and check ph daily. Will use baking soda to buffer if it starts to fall fast. But, it could be that I got the buffer rebuilt using the baking soda. I still want to get some crushed coral to completely control it. I'll keep you posted, and thanks for the help, tips and ideas.