Does brightwell magnesium contain phosphate?

[jimmypencil]

I have a 50 gallon tank and have dosed about 100ml of brightwell magnesium into my tank spread out over the past two days.

i test phosphate daily and yesterday (before magnesium dosing) it was .08 and just now it tested at .24. Nothing changed with skimmer, feeding, no fish deaths, pretty much nothing that could affect phosphate that I can think of.

I just want to rule out the magnesium dose as a culprit for adding phosphate because it’s the only things that’s changed and my phosphate has been locked between .05-.08 for months.

when phosphate is too low I dose neophos, when it is too high I dose phytoplankton from Eldridge here on reef2reef.

 

[Randy Holmes-Farley]

No, mangesium additives do not typically contain phosphate. If they did, insoluble magnesium phosphate would precipitate.