So I just set up my 90 in the apartment. I have a 12g top off tank and had the tank up and running for about 3 weeks. Lighting is an Outer Orbit 2x250 MH
and 4x T5. Salinity was 1.024 after my last water change. During the 3 weeks top off was about 5-7 g a week although I always keep the windows open.
I left on business for 5 1/2 days. When I got home saturday the top off tank was empty and the tank was down a good 5-6 inches from the top. I immediately started making RO
water but when I checked salinity it was 1.026 ?
I got the tank level back up about 3 inches and now salinity is 1.021. I still need about another 2" of tank fill but I'm trying to figure out what happened ?. My first thought was excessive evap because the apartment was closed up for 5 days but then I would have expected the salinity to be much higher and would have expected to be able to refill the tank and get back to 1.024.
I'm mixing some new water and plan on topping off the tank to get the salinity back up a few points and I will apparently have to get a glass top before my next long trip.
It's seriously like someone came in and took 15g of water out of the tank. There are no leaks, no signs of water on the floor or anywhere.