View Full Version : How much cal/mg can I dose in a day?

07/30/2017, 04:56 AM
The tank is just short of 6 months, 60gallons not very much liverock. I only have 3-4 corals, one Pocillopora that is growing well but I killed off my acro when I dosed too much, alkalinity went from 6-8 in a day.

Todays test show.
KH 8
Cal 380
Mg 900
Ph 8.2
temp 80.5

How much Red sea foundation is safe to add? Dosing mg or cal has no effect on livestock other then corals?

Ron Reefman
07/30/2017, 05:18 AM
In a tank that size with only 3 or 4 corals, you shouldn't have to dose at all. Normal, regular water changes should more than keep Ca, alk and Mg in line. How often and how much do you change?

What is 'not very much live rock"? Give us a number in weight (kilos or pounds). And why don't you have more?

And if you only have 3 or 4 corals, why are you screwing around with Red Sea Foundation? IMHO it's mostly snake oil anyway.

Your dKH looks OK, but your Mg and Ca are low, Mg is probably too low.

07/30/2017, 05:48 AM
20-25lbs of rock, took one stone around 5lbs from my old tank the rest was dead rock. My old tank ran for 2 year did almost no testing at all only had soft corals and lps and upgraded because muschrooms overran the tank.

I have been real lazy when it comes to testing in the past, but with the new tank and because I have never had any success with other sps then pocillopora and other "easy" sps I thought I would start testing everything. I also noticed that I have very little coralline growth.

I have never had to dose anything in past tanks but this is the biggest I have had. Water change 10% every 10 days.

Martin Kuhn
07/30/2017, 07:46 AM
My advice: first put effort in checking "what you measure is correct"

A Mg value of 900 seems nearly impossible if you use standard salt mixtures

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07/30/2017, 08:05 AM
I agree: it's hard to be that low. And misreading tests, or expired test kits, can really screw things up. Personally, I use Salifert brand, which use marks on syringes to tell you the numbers for alk, cal, and mg. You must be careful to read and follow directions, to fill the syringe BY the directions, to be sure the BOTTOM (not the top) of the black plunger is resting on the start point, and to do the gentle shaking of vials for the required. I don't know if misreading could be at issue, but it is a technical learning curve. Expired tests can give you bad results. Some are only good for a year or so, then can go wonky on you.

07/30/2017, 08:50 AM
I use red sea tests but there might be something I'm doing wrong. But something is off anyway since I only get film algae, no coralline. I will keep testing even if the value is off I can see if it's stable or not.

07/30/2017, 09:04 AM
THat is true.
Your low mg level is a reason you wouldn't have coralline. Get it to 1350 and if you have any, you'll start seeing it develop.
To answer your original question, btw, the best procedure is to dose only as much as the instructions say, wait 8 hours for it to fully dissolve and work its chemistry---then test again, add again. Bring your magnesium up first to 1350, because it is the stabilizer of the other two. Then start working on your alkalinity. Same routine. Get it to 8.3. Once you've got both of those behaving themselves, bring your calcium up to 420. NOW---add 1-2 teaspoons of kalk per gallon of water in your autotopoff reservoir, and just let topoff water supply THAT to your tank. The addition of that calcium powder into the situation will keep that ratio of readings locked so long as the topoff water keeps coming AND so long as your magnesium stays above 1200. That is the 'floor' of the readings. Keep it up around 1350 and your other two readings will stay where you put them so long as the kalk-water mix keeps coming in as topoff. Kalk is how I supply the stony coral in my tank, and it has been a standard method since, oh, the 1980's. Kalk is also cheap. In the states, I use Mrs. Wages Pickling Lime, which is literally used to make pickles, no joking.

07/30/2017, 10:51 AM
Will do, thanks for all the help appreciate it. Already have an ato with kalk.

07/30/2017, 05:41 PM
I agree that the result is suspicious. Getting a level that low generally would indicate a bad batch of salt. I'd proceed cautiously, and definitely get another opinion on the magnesium level.