Low water level - normal salinity

[swoons]

I’ve been topping up every couple of days with distilled water but I’ve noticed my water level is pretty low than normal but my salinity is in the range I keep it at (1.025-1.026).

I’m thinking now if I top my tank with fresh water I’ll drop the salinity too low. Wondering if I should add salt water or what?
I top off my 40g with a gallon of distilled every couple of days.

 

[Crabs McJones]

Mix up saltwater to the salinity you want and fill up with that, and then go back to topping off with freshwater

 

[Fishfinder]

It sounds like evaporation

 

[cmcoker]

Verify your test, check with a lfs or reefer friends refractometer. Your refractometer could need calibrating.

If salt is disappearing with the water, it could indicate a leak. Have you checked under and behind the stand for a slow drip?

 

[Waters]

Also check your filter sock section (if you have one). Depending on the sump, as the filter socks become dirty, that compartment holds more water since it isn't filtering through the sock as quick. Since you aren't using an ATO, the level would just drop in your return pump section.

 

[Super Fly]

depending on tank location and ur area's climate, some tank may experience higher rate of evaporation. My 93 cube uses 5-10 gal of ATO water per week depending on the weather. r u using an ATO?

 

[Brew12]

You also lose salt with skimmate, so it's normally to need to bump it up on occasion.