Mg and DkH insight

The reason I'm asking is near the end so please read why I'm asking. I'm hopping on some insight. Thanks

Anyone able to explain why Dkh and Mg are so need to dose. I know that they in theory contribute to coral growth. A simple expination would be cool. Not that rocket sience crap if you could. I've read 100 things that just go way to in-depth and just confuse me. Perhaps how one effects the other.

The reason I'm wondering is a good friend and very long time reefer and saltwater store owner DOESN'T dose anything but Ca and his tank is freaking amazing. it's around a 300g mixed reef with alot of sps and lps ect. How does he get away with Only dosing Ca and have such a nice tank? All of his corals look very healthy and appear to be growing very yell. Also little to no algea problems at all.

Thanks alot

 

He probably changes water a lot or has a kalk reactor. Mg provides stability to the number. Alk provides the carbonate that the corals need to make their skeletons. The easiest ion for corals to uptake is bicarbonate to build their skeletons.

 

No he says Just Ca and nothing else

 

Basically and in a really easy way to understand, Magnesium is kind of a binder for both calcium and alkalinity and help to keep the amounts of both stable. If Mag is low it is harder to keep either of the others at the levels that they need to be at, no matter how much you add to your system.

As for how much your friend has to "dose" it has to do with how old the tank is, how large the tank is, How often and big the water changes are made, and last how many and large the corals he has in it are. And if that 300g tank is as full as you say and is an older tank, well I hate to say it but I really think he is yanking your chain about what he does or does not dose.

My tank (75G) was fine for about 8 months then I had to start adding Calcium, in small amounts. But now at 2.5 years I dose all three regularly because my corals have all grow and are growing and using it up at a rate faster than water changes can replace them.