Ph problems in my LPS aquarium

[mussel20]

My lps reef aquarium's ph is fluctuating from 8.3 to 7.8. When I buffer the water, it will raise to 8.3, but a few days later it will go back down to 7.8. I have been keeping this aquarium for about a year. At first, I didn't consider this a huge problem, but now I am getting worried because it has been persistent for about 3 months now. Does anybody know why my ph keeps falling? How do I fix this problem?

Thanks,
Jeff

[isjg]

what are you using for buffer?

[sarduci]

What kind of testing do you do for params? Quick strips or individual test kits?

Also, try taking a cup of water outside for a few minutes and mixing it up really hard. Check the PH then and see if you have excessive CO2 levels in your house that may be causing it to drop.