salt in top off-how much?

[boxfishpooalot]

Hi Randy,

On my skimmer, I skim wet. Every day I skim .46gallons liters of wet skimmate. I notice that the salinity will change too fast for my likeing. This can effect livestock.

I want to try and keep the salinity with as little fluctuation as possible.

So I top off 2.5 gallons of pure water daily(on average) and skimm out .46 gallons (average) of water daily.How much salt would I add to the pure top off water to maintain the sg at 1.025?I have instant ocean salt. I know your not going to want to do some crazy math calculation. So to let you know, I would be most happy with just an approximate guess to avoid my frustration.

Thanks for any help Box

 

[DrBDC]

You could measure the salinity of the skimmate I guess and replace with the same salinity water. At least that makes sense at 6 am.

 

[Randy Holmes-Farley]

The skimmate should have salinity close to seawater, so I'd use top off that has a salinity of 35 x (0.46/2.50) = 6.4 ppt.