Raising salinity formula?

[Biokabe]

https://www.hamzasreef.com/Contents/Calculators/

There's every salinity calculator you'll ever need (and a handful that you never will).

For your situation, you can use this calculator:

https://www.hamzasreef.com/Contents/Calculators/SaltwaterTopOff.php

 

[DocRose]

If I know the exact amount needed for 1 gallon of water to get my salinity where desired, I can then dilute it. I can use that 1 gallon in 20 gallons of top off water to get the desired effect.

I... I... I'm not sure what you mean. Even IF this was the right way to do it, diluting it completely nullifies the fact that you were trying to find out what the SG if 1 gallon had to be, in order to add it to 70 gallons and raise that 70 to 1.026.

Now, what I will say is that diluting it over 20 gallons of top off water, is no different that my original suggestion of making a batch of top off water that is 1.026 and using that in your ATO (or manual top off). And if you want to "speed up" the process, just increase your evaporation rate.

No, that is a different question, if you are replacing evaporated water
1 + (70 × 0.0015)/20 = 1.00525 if used in ato, and 70 g tank

If added to 70 g in 90g tank then 0.00525 + 1.026 = 1.03125

This again confuses me. I feel like there's missing math here, such as the rate of evaporation and how long of a "raise the salinity" process you're aiming for. Both of those variables play a factor in determining what the salinity of the top off water needs to be.

EDIT - OH! Another variable is how much water the ATO holds, and if you're aiming to do it in a single batch of that ATO water. All-in-all I'd say @Biokabe has given the most useful tool here.

 

[mindme]

Just top off with saltwater instead of RODI water until the parameters are right.

No formula needed. You can mix it a little saltier and get there quicker, but you don't want to get there too fast.

 

[chadfish]

I don't plan on doing it all at once. I just need a reference point.

I just raised from 1.025 to 1.026 today. Did it all at once. Not so fast as to see a heliocline or anything, but within 5-10 minutes. Worked fine. No issues. I have a mixed reef with SPS, LPS, softies, anemones etc.. No issues whatsoever. Not a fluke, these animals are very adaptable to small changes.