Salinity calculator
 

90 gallons with a SG of 1.032
I want to be at 1.026
If I take out 4 or 5 gallons twice a day and replace with RODI, how long would it take?
Good plan to get back no normal?

If that's 90 g of actual water volume, you would need to remove about 16 gallons of water. Personally, I'd do about 2 g per day via autotopoff, if I had a slow (peristaltic) pump, maybe in two shots. I'm assuming there are corals in the system, or other invertebrates (osmoconformers).

The math:

1.000 SG means no salt content, so
    .026 / .032 = .8125
is the amount of salt to keep.

So the amount of salt water to keep is:
    .8125 * 90 = 73.125

Thanks you Bertoni

His did you get the = .8125 ?
Yes, about 90 G if water
Full reef.
I am using a litermeter for top off so I could take 3 gallons out every morning and have the litermeter replace in 24 hrs.
PS I don’t recommend the IceCap salinity tester.

Oops, typos fixed. Sigh! The tanks current SG is 1.032. The target is 1.026. 1.000 actually corresponds to zero salt, so you want to dilute down to .026/.032 of what is in the system, which is .8125.

Along these lines since im not a math wiz like you
If I have 100 gallons at 1.026 and I want to drop it to 1.023 how many gallons of saltwater do i replace with freshwater?

I get about 11:
.026(100 - x) = .023 * 100
2.6 - .026x = 2.3
.026x = 0.3

I might try half that and see how it goes. I am assuming it's 100g of actual water volume in the system.

Thanks

You're welcome. Please let me know how accurate my math was.