A Few Questions

I am finally at the point where I am able to keep my Ca, Mg and Alk steady, but I have some questions. Right now I am keeping Ca at 450, Mg at 1420 and Alk at 8.5. I am using the BRS two part plus Mg for all of my dosing. Everything I read says to dose equal parts Ca and Alk, but I either have low Alk or high Ca when I dose equal amounts. I dose 30 ml of Ca, 40 ml of Alk and 10 ml of Mg to keep my numbers stable. I am using Red Sea Coral Pro salt with specific gravity at 1.025 and do weekly 10% water changes. My pH is also at 8.6 right now. My corals are finally showing good growth, but I want to make sure I am not on the brink of disaster. Here are my questions:
1. Can any harm be done by not dosing equal parts of Ca and Alk and is that normal?
2. Am I doing any long term damage when my pH is 8.6?
3. Should I stop dosing Mg since I add very little and it stays a little elevated?
I don’t know if it matters but phosphates are steady at.02 with a Hanna checker and nitrates are between 1 and 2.5 on an Elos kit.

 

It is rare that 1 to 1 dosing works so don't worry there. Your levels are fine on the big three. You can dose the Mg how every you like to keep it steady at the level you wish.

The high pH can definitely cause a problem with increased precipitation of calcium carbonate from the water and will most likely inhibit uptake of minerals in stony corals. Getting it down to 8.2 or 8.3 is a good goal. Do it slowly and don't chase a value if your tank is doing well.

If you are using sodium carbonate switch to sodium bicarbonate since it will not raise the pH as well as sodium carbonate.

 

Thanks! I am using the sodium carbonate and I will switch to sodium bicarbonate.

 

+1 on 2 in 10

its not uncommon for as low as 7ppm calcium to be used for every 1 degree Dkh that the typical reef aquarium drops (do not always expect the 20 ppm to 1 ratio that many of the formulas are based on

The reasons for this are
Strontium and magnesium to name but 2 are interchangeable with calcium as far as the needs of corals, coraline etc are concerned
additionally some of the Alkalinity/ carbonate ions go towards maintaining PH
some tanks have higher demands on carbonates than others, and these set ups do need to have additions adjusted to compensate for their specific demands

Magnesium - mine is almost identical to yours and despite goods growth and a back and both sides of the aquarium being over run by Coraline, my Mag varies very little on a weekly basis even without this being dosed at all


Steve