How to measure calcium so I can balance maganesium?
Im using RO water in a 20 gallon long. Big gray rocks with white strips in it. My kh is about 9 or 10 and my gh is around 7.
How can I figure out how much calcium these rocks are putting in to get my gh that high, or do I assume it's all calcium as rocks typically dont have magnesium?
I'm realizing my magnesium is probably way too low in terms of Ca:Mg ratios and trying to fix it.