alk and calcium problems

[pdlman]

I am having major problems keeping my alk and calcium up! I have been adding buffers everyday for the past 3 weeks and they still wont stay up overnight. I have been adding Seachem reef bulider for the alk, and Seachem reef advantage calcium to raise calcium. Both of the readings are as follows- KH/alk 7.0-2.51 meq, calcium is always at 370 ppm. I use Salifert test kits and have them checked at the LFS. My tank only contains two SPS a boat load of zoanthids and a monster toadstool. The tank has been up for years and I do a change about every month, whenever the trates get to high, with Coral Life salt. Any ideas would be great because I am witts end.

[pdlman]

bump, and PH is 8.3

[pdlman]

AH! I just read a thread on magnesium, that might be my problem. No LFS in all of Saint Louis sell them!

[JohnO]

Magnessium levels could certainly be the problem, but test first, if low you can use epsom salts to raise the Mag level.

John