Figuring out Kalk dose..

Tetra84

New member
Hey reef chemists..

Got a question for you guys, so i'm trying to figure out the calcium and Alk balance of my tank based on the demands of what I have right now..

I started dosing Kalk at a rate of 3 tsp per 5 gallons last week, I've been testing the calcium and Alk levels and this is what i've got the last 5 days:

Date / Alk / Cal
9/6 9.1 405
9/6 9.2 440 (did calcium correction this day)
9/7 9.1 435
9/8 9.1 430
9/10 9.1 415-420

Mag levels around 1500

as I can tell, it's loosing about 5ppm in calcium a day with my current rate of 3 tsp per 5 gal of ATO water. I guess I should up the dose to 5 tsp per 5 gallons and keep testing? What i'm wondering is why over the last week has the Alk also not really declined?
 
Are you dosing a pH buffer into the tank? They all are alkalinity supplements, despite the advertising claims. Tap water can add a lot of alkalinity, too. I'd figure this out before worrying too much about the calcium level. Have you gotten a second opinion on the alkalinity kit?

The other possibility is noise in the calcium kit.
 
no, not doising any ph buffer, and using RODI water for the ato and in salt mixes. What do you mean by 'noise' in the calcium test? The Alk, Mag, Cal tests im using is by Red Sea and it says its good till 2014.. I haven't gotten a second opinion, but I guess I will go have it tested by my LFS.. Maybe I should also get one of those digital hanna meters instead of trying to match colors.. kinda find that frustrating.
 
Our test kits are only so accurate, and ±20 ppm is actually quite a reasonable expectation, so the numbers might not mean much yet.

The alkalinity should be declining unless there's some hidden source, so I'm puzzled, too. Any water changes done? They can boost levels here and there.
 
I try to get weekly water changes done (10%), but i haven't done any since I started testing every day.. the only thing I am dosing is the Kalk which I guess should keep the alk stable right if it's balanced? it just seems as though the calcium is the one being depleted..
 
You might be right, in terms of the levels measured, but it'll take some time to sort out the issue.
 
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