water chemistry question

[bprewit]

My tank is 120g and I try and maintain the following parameters:
ammo-0
nitrite-0
nitrate- <5
ph 8.2
Alk- 11dkh
calcium- 440
magnesium- 1400
I recently stopped adding calcium and buffer for a few days and tested every , and alk to try and see how fast they were being depleted. Hard corals are: oevening for calcium, magnesiumne medium colony montipora digita, 5" crocea clam, two small branching hammers, one medium torch, medium sized open brain, large favites brain, and a couple of small Pachyseris. The tank is growing lots of coralline finally and cleaning it from the front glass every few days when the spots are small. I use seachem reef buffer and reef builder for alk and half of the kent two part mix for calcium. I use epsom salt on occasion for magnesium and I also dose about 2ml of iodine once a week and do monthly 10g water changes with oceanic salt. From testing this is what I found:
Calcium dropping 20-25/day
alk dropping .50-.75dkh/day
mag only small change over 5 days.
The alk drops quite a bit per day and I am wondering if that is normal or if my water parameters are screwed up somehow? I want to set up a drip system with the additives to try and keep everything stable especially when I am out of town on business trips. What is the best way without a calcium reactor to keep things stable?

[gjuarez]

yeah your alk since to be dropping a lot per day. Well to be quite honest, I dont know if is a lot but I know that it will be depleted by a substantial amount if you leave for an entire week or weeks. The significant drop in alk could cause your ph to fluctuate and that is the danger I forsee. Talk to GaryP on this one, he is the expert in water chemistry.

[Richard]

Your corals certainly are not using that much calcium. Some will disagree here I'm sure, but in my experience when you use calcium chloride in an unbalanced way as you are then you tend to precipitate out alot of calcium and carbonates (i.e. calcium carbonate).

My suggestion would be to do some fairly decent water changes to get things back in "balance" and then go to using just a two part additive like B-Ionic, C-Balance, or both parts of Kent AB. If your a DIY'er then you can make your own. The recipe is in the REEF CHEMISTRY forum on RC or just get with GaryP for it.

I think anytime your going to rely on calcium chloride as your main source of calcium additive you will need to do more than the ~10% per month that you are doing. Probably weekly 5% or monthly 20% water changes. And then maybe double that percentage every 4 -5 months.

[gjuarez]

I use B Ionic and it works great. I feel it is the next best thing to a calcium reactor.