Water addition substitutes

[DeepThought]

Hi

Hopefully a silly question but I'm taking my first tentative steps into water profiles and was curious about substituting additives.

Say I need to add Ca2+ Mg2+ SO4 and HCO3 to my water, does it matter where those ions come from? For example, to add SO4 ions, I can use either Gypsum (CaSO4) or Epsom Salt (MgSO4) and accept that using either of these will also have an effect on the levels of calcium and magnesium respectively.

I guess my real question is, so long as the water profile after additions matches the target profile, does it matter how I get there? I only ask because some additives seem easier to get hold of than others and I'd rather not have to mix up suppliers and double or treble my postage costs... also I'm genuinely interested.

Hope that all makes sense.

Cheers

 

[Agentgonzo]

You're entirely correct. If you accept that the magnesium/calcium levels will be different, the it doesn't matter whether the sulphate ions come from gypsum or epsom salts. The sulphate ions are the same in both.

The salts 'disassociate' (ie, split up) into the metal and sulphate ions in solution.