I'd also try raising your calcium as well. I like to keep mine up around 430....

Ive been trying to raise the calcium as well, but I suspect the low mg was keeping it down. I will have to try the dry additive, but the calculator says I need like 600 table spoons? Does this sound right?

Ya, Thats probably right. I needed to dose about 3000ml of the DIY mix to bring my Mg up to where I wanted it, and I only have a 125 gal.

You do need a lot to raise it, dont raise it too quickly, as it can stress your corals. Just remember it is a salt and raising it a lot will also raise your sg. I found if you need to raise your mag by a signigicant amount it is better to add it either with a water change or at the same sg as you currently keep your system at.

I'll hook you up with some mag. crystals for free. I have tons extra and never use it. I'd rather give it away then let it continue to sit in my basement.

In regards to the link between Calcium and Magnesium, mag. facilitates the uptake of Ca. in SPS. So raising your Ca one day and Mag. the next can help you get things back on track. I used to dose Ca. one day, and Mag & dKH the next, one in the morning, one at night.

Michika, those crystals would be great. I can pick them up when I pick up the food.

Thanks!

Yes it blows your mind how much additive is required to bring them into the correct levels. That is why these premixed additives available at you LFS do not seem to do anything. I use 22 table spoons of mg added to my mix for a 45G water change using IO salt. This will bring the mg levels to 1400. Once I got my mg to 1350 in the tank I only have to ensure that my water change water maintains those levels. I seldom have to dose mg between water changes. I do the same for ca.

Tom R

You'll find IO low in Ca and Mg right out of the pail, but once you know, it's not big deal to supplement your change water.

With different pails I'll get for Ca 275-325ppm and Mg 900-1100ppm. Natural Salt Water is about 380-450ppm for Ca and 1250-1350ppg Mg.

So I would have been at thins a long time adding 100ml of liquid suplement each day. LOL. I'm glad theres so much good advise on this site!

Thanks everyone.

Rene

I too have had problems increasing Mg and Ca levels. I have been using liquid supplements but that has become expensive. I have been using Reef Crystals but have not been impressed. I have tested new salt water mixes at 1.026 sg (using refractometer) and got readings of 360 ppm Ca and 980 ppm Mg using two different brand test kits. I will be switching to a new salt.