Top off bring salinity and DKH down

[LilysDad]

So this week I have use up around 8gallons for top off using rodi water and has brought my salinity down from a 1.025 to 1.023 and DKH from 8.0 to 7.4 what may be the problem?

 

[Nanojoe]

sounds like you are not topping off to the same water level each time.
Are you topping off by hand?
if so mark the tank with a sharpie so you know thats were to top off each time.

 

[ZoWhat]

Topoff replacement volume = evap water + skimmed out saltwater

No more. No less.

.

 

[LilysDad]

Sump Has a top off container

 

[moz71]

How are you testing salinity? Sure measured correctly? Are you dosing alk consistently? Sure alk is not just dropping by though absorption?

 

[LilysDad]

Hannah salinity tester I’ve calibrated before testing and Hanna DKH. I just set up the tank 1 month ago I was toping off with saltwater before and everything was stable until this week when I top it off with rodi

 

[FairbanksReefer]

Salt doesnt evaporate with the water so you shouldnt lose salinity from evaporation. My first thought would be are you testing salinity correctly and accurately. If you are confident you are then the salt has to be going somewhere like skimmer or a leak. If you have a leak somewhere then that would do it.