mixing RS Coral Pro

[gdwats]

Would you mix 24+ hours b4 adding? I am getting a sump tomorrow and will be adding 10 gallons of saltwater to the system.

 

[gdwats]

it is 65 gallon now

 

[Randy Holmes-Farley Verified Community Expert]

I would mix it until it dissolves (say, 8-12 h), then let it sit (unstirred) until you need it.

Stirring longer is not needed, and with some salts, like this one, the heat from the pump seems to cause excessive precipitation of calcium carbonate.

 

[gdwats]

Wow. I just mix up in 5 gallon jugs w/no pump. Dissolves fine. I have heard with RSCP over 4 hours is an issue. Not sure why? I've tested alk and it doesn't lose it. It is capped.

 

[gdwats]

Hmmm, heat from a pump causing precipitate just seems wrong, as in general solubility increases with temperature. It must react with CO2 in the air over time producing the CaCO3? I suppose Ca would obviously fall out and Alk would suffer if that is the case. Leaving capped should put a stop to that. But why push it, I'm going with a 3 hour hold time.

 

[Randy Holmes-Farley Verified Community Expert]

Well, intuition isn't always right.

Solubility of calcium carbonate decreases as the temp rises in seawater.

That is why you get deposits on pumps and heaters in reef aquaria.

I discuss it here:

Chemistry and the Aquarium: Calcium ? Advanced Aquarist | Aquarist Magazine and Blog

 

[StikHedRon]

I would mix it until it dissolves (say, 8-12 h), then let it sit (unstirred) until you need it.

Stirring longer is not needed, and with some salts, like this one, the heat from the pump seems to cause excessive precipitation of calcium carbonate.

Randy, You would you say this recommendation for all salts?

 

[Randy Holmes-Farley Verified Community Expert]

Well, unless they contain organics they do not need any mixing after about 24 h. I store my IO unstirred for weeks.

But most mixes don't seem to have the same rapid precipitation that RSCP has, but I don't know why.