Changing water and keeping salinity level...

[Glomgold]

Let's say my aquarium has a specific gravity of 1.023, and I do a water change. Let's say I drain 5 gallons of water out of my tank. When I go to add that water back, would I make 5 gallons of saltwater that measured 1.023 and then add it, or would the replacement water have to be a lower salinity?

 

[electrikat]

We always make the replacement water as close to the tank in salinity and temp as possible.

 

[malkore]

kat is right the replacement water should be the same salinity and temp as the tank water. I tend to mix my water 48 hours in advance. then if I didn't add enuf salt, or added too much, I can correct it, and still have a full 24 hours of mixing and stabilizing.

Since you top off for evaporation with pure water (preferably distilled or R/O) rather than sea water, your tank salinity *should* stay constant.