Cannot keep up with the calciium demands!!!

[3.99AfterTaxes]

Tank 800gal w/ sump, 90% SPS & clams
Calcium reactor - Aquamedic 5000, pH 6.0, 45 liters/day
Kalkreactor - 15 liters topoff

kH 10 if pushed, drops to 8 within three days
Mg 1740 ppm

Here's the problem, the highest I can get the Ca up to is 420 ppm. If I leave it for a week, it drops well below 380.

Possible solutions:

- add another Ca reactor? Will this cause pH problems if the effluent is exhausted into my skimmer?
- dose Calcium chloride? What happens to the extra chloride ion?

Coral grows relatively quickly.

Any help would be appreciated.

Thanks in advance!

[bertoni]

I think I'd add another calcium reactor. Dosing calcium chloride and baking soda would also work, although it's more tedious. The dosing would also raise the salt content of the water over time. That magnesium level is very high. Is that a test kit error?

[graveyardworm]

Could the high magnesium be making it difficult to raise Ca and Alk?

[3.99AfterTaxes]

Nope. It was always like this. There's a LOT of SPS and clams in this tank.

I have a reactor to add, but was wondering if additional effluent is going to cause problems with my pH balance.

[Spuds725]

If you continue to dose the kalkwassar, your pH should be able to tolerate it. What is the pH range currently??.... are you using a pH controller for the kalk and/or calcium reactor??