JennM;584429 wrote: Salinity has a higher starting value of MG than most salts - your batch should have that on the analysis sticker. 1250-1350 is what we aim for. Some people raise it higher than that for various reasons (nuisance algae and cyanobacter control etc). Typically it should be approximately 3 times the calcium. So if Calcium is 450, MG should be 1350.
Light isn't as important to coralline as you might think. I've grown some amazing coralline under regular output fluorescents.
You might want to dose 2 or 3 times a week, at least until you get it to where it needs to be, then back off a bit and see what you need to do to maintain it.
I had no idea how important Magnesium was until I saw the results for myself - like I said, I was the only one dosing, and only every 2 weeks at that. It was a big tank (225g) so I was pretty generous with the stuff (I was using Tech M on it at the time, and we still use it on that tank today). By week 6 I was pretty discouraged - I'd seeded it with some scrapings and a few snails that were well covered in it... but on that 6th week I saw a dime-sized patch of coralline. W00t! 2 weeks later there were 3 or 4 dime-sized patches. A couple of weeks later there were more, and they were quarter sized, and it kind of went exponentially after that.
It would have taken less time if the tank owner was more hands-on... but it did take off eventually.
Similarly, if people take CA supplements that don't have MG in them, they might as well flush the pills (and their money) down the toilet. Calcium alone is not enough.
Jenn