Dosing Magnesium

[robertpower3]

Quick question. I have started dosing magnesium in order to keep my calcium levels at 450. For awhile the calcium in my tank was beeing sucked out faster than I could add it. I tried Kent's Kalk, Kent CB, and finally reef sucess. I would like to know why I would have a magnesium deficiency. I use Di water and red sea salt. I do 30% water changes monthly. Does anyone else dose Tech M regularly?

[MikeP]

Robert some plants/macroalgaes (mangroves and calcerous alages in particular) uptake a fair amount of magnesium but you'd need a lot to see such a noticable drop. You might search the archives on reefcentral under Randy-Holmes-Farley's board for magnesium depletion I know I read about this there a few months back - If I remember I'll dig it up later.

-Mike

[Jimnorris]

What is your mag level?
Jim

[robertpower3]

don't know. I don't have a magnesium test kit.

[matt]

I agree with Josh here. I'd bet you don't have a magnesium deficiency. Also, I'm not sure why reefers tend to think that calcium levels above NSW levels are so desirable, like more is better. Don't forget that things like ph and carbonate hardness affect calcium solubility, and your goal here is to have stable levels that allow usage by corals and maintain ionic balance. I personally have never had calcium levels much above 400ppm, and my corals are fine; usually it hovers around 380-420. This is with a calcium reactor and KW dosing, and is in line with what I've read are normal NSW levels in the reef area. The only reason for bumping calcium is to guard against serious depletion, like down under 300ppm.

HTH
Matt

[robertpower3]

I started dosing magnesium because I added calcium eveyday for two weeks and could not get my calcium levels above three hundred. I talked to one of the LFS guys and he told me to dose magnesium. He said that he spoke with a Kent representative that told him about this problem relating to low calcium levels. After dosing with magnesium I can now keep my calcium levels above 400 ppm.

[Derek B]

Robert,

I went through this same thing a while back. First off, like Josh said, don't dose things you can't test for. You really up your chances for a catastrophe. Salifert makes excellent test kits. IMO, all you need is a Calcium and Alkalinity kit and a pH probe, but go ahead and get the Magnesium kit to put your mind at ease.

Magnesium is usually not the problem. My problem was that I was not adding enough calcium. Recommended dosages are meant for maintaining calcium levels, not rising them. Once I kicked up the dosage, the calcium level came right up. I added magnesium for a while and I now realize I wasted a bunch of money on those additives for nothing. Your water changes are sufficient enough to maintain good magnesium levels. Hope this helps.

[Chuck]

Does anyone know what remains in water that has been through the RO/DI process? I have a unit that cycles water through both and the TDP meter registers (6) for straight RO and (0) when using the DI chamber.
I use kent trace elements / and sea chem calcium advantage and reef builder. So far my test have shown CA always around 400 - 420. I do a top off about twice a week but only dose per the instructions and no more unless my test reflect a need. I test twice a week. I had always assumed that water from an RO/DI unit would need some help beyond the normal additives found in salt. Also I just realized that Distilled is actually inbetween Ro and Di. A friend of mine is a culligan salesman and has some very expensive water testing kits and had told me about the Distilled water and how it does have a level of minerals in it. I will have him test my DI water just to see what if anything remains.