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View Full Version : How bad is Mg = 1100 ppm


acroporas
12/12/2006, 11:08 PM
I can not keep my Ca/Alk levels up. I'm trying to deside if my Ca/Alk demand is extrordinarily high or something is wrong with my chemistry.

I raise my Calcium to 400ppm and Carbonate to 210ppm. Using Kent TurboCalcium and Seachem Alkalinity Buffer. 3.5 days later I test again and my Calcium is 300ppm and Carbonate 160ppm. That is a drop of Ca of 30 ppm per day.

During this time, I was replacing all of my evaporation with full strength Kalkwasser by a dosing pump. Ca of kalkwasser solution tests 840 ppm and I was adding 4 Liters per day to about 65 Gallons of water.

These levels (300/150) will then hold steady so long as I keep dosing the Kalkwasser.

I could accept that kalkwasser alone is just not going to cut it, but I'd rather not have to not yet admit defeat.

I've never tested Mg but after reading how popular Mg has become on the this forum and reading that low Mg could be the cause of Ca/Alk problems. I went out and purchased a Mg test expecting to have very low Mg.

So I did the test and my Mg is 1100 ppm which does not seem that low. Do you think raising MG would solve my CA crisis or am I going to have to resort to dosing Calcium / Alkalinity manually?




In case any of this information is usefull.

Tank Info. 75 Gallon aquarium with 1/2" of a stubstrate composed of 50% Calcium Reactor Media (I don't remeber which brand) 50% sand and about 35 Lbs of live rock.

Filtration: No sump, No skimmer, and no filtration of any sort. Just a Mod'ed MaxiJet for circulation.

The tank is a mixed reef with 50% LPS 25% SPS and 25% soft Coral. Coral load is very high (I can't figure out how to get any more coral in there) + there is about 1/2 Gallon of Halimeda. There are 2 fish a yellow tang and a blue tang. Coral growth is good for everything except my Acro's (LPS and Monti's are doing fine) which are suffering from the low Ca.

The tank has been up and running for 4 months, though the rock and sand (though not the Ca Reactor media) have been in aquariums for many years.

Salt is Instant Ocean. I havent done a water change since the tank was set up. Other than Ca, Alk, the only other parameter I regularly test for is Nitrate which is allways 0.

bertoni
12/12/2006, 11:14 PM
I suspect you're going to have to dose manually. You could also consider spiking the limewater with vinegar, which allows dissolving more lime into the mixture. Another option would be to try to increase evaporation, possibly with a fan, although it's easy to overdo it, at least in my experience.

This article discusses lime, including the use of vinegar:

http://www.reefkeeping.com/issues/2005-01/rhf/index.php

I'd raise the Mg to 1275 or so, but not expect it to help much.

dga
12/13/2006, 01:41 AM
i could never keep my calcium and alkalinity to the proper levels until i tested the magnesium which was 1120ppm. i dosed "kent tech m" i now have the mag at proper levels and now topping off with just kalkwasser keeps my calcium and alk levels much more stable. ive only had the mag up for awhile now, and long term will dictate weather i will have to supplement cal and alk if any.

Randy Holmes-Farley
12/13/2006, 07:04 AM
I agree that I'd raise the magnesium to 1250 to 1350 ppm, but whether it will make a noticeable difference in any particular way is hard to say.