Questions about your two part recipes

[joekool]

i have been using your An improved do-it-yourself for some time now.

My question is for the magnesium recipe Epson salt versus the Epson salt and magnesium chloride I just want to know what's the difference when using either or how it affects the tank.
the recipe didn't necessarily state how it affects the tank differently by using just straight Epson salt but it did list the amount of sulfate that would be in there versus chloride and magnesium

I let my numbers drop pretty low while away from my tank and came back to bryopsis after being gone for years and the last time the only way I could get it to go away was when I use tech m magnesium at 1600 ppm for an extended period of time. I got Mg up from 1100 to 1590ppm now but want to maintain 270 gallons of water at that ppm

I think epson salts is probably the easiest and cheapest way. Do you see any reason not to use just 8 cups of epson salts vs BRS mg sulfate and mg chloride?

 

[Ewilson]

I'm also curious about the straight epsom salt vs epsom and mag chloride it seems to me the epsom salt would be the easier of the two to make

 

[Knapp870]

If I remember correctly, I think the reason to use mag chloride over epsom (magnesium sulfate) is to reduce the amount of sulfate you introduce into the tank. Over time it was shown to build up to significant levels.

 

[Ewilson]

Most 2 part recipes call for mag chloride and mag sulfide to be mixed together I believe Randy's recipe does it this way

 

[Knapp870]

Yep, this helps prevent so much mag sulfate being used. Hence less sulfate in the system.... "Using magnesium chloride improves the recipe and eliminates a primary concern with the previous recipe: the potential buildup of sulfate over time."
http://www.reefkeeping.com/issues/2006-02/rhf/

 

[Randy Holmes-Farley Verified Community Expert]

We don't really know what impact high or low sulfate (relative to chloride) has on a reef tank, but using Epsom salt alone will make it rise and using magnesium chloride alone will make it fall. That's about all I can say about it, other than the suggestion that keeping it reasonably close to normal would be my goal.