Nano 3G Salinity Problem

[TheHuff]

I have just begun a Nano tank, 3 Gallons. i have about 3 Lbs of live rock along with 3 blue legged hermit crabs, 1 zebra hermit crab, and 2 turbo snails. Everything Seems to be fine, except that the slainity is constantly dropping. Every time i check it with my Hydrometer it is lower than the previous time. When i look at the cover of the tank i can see a great amount of salt that is on the top. Anyone know a way that i can keep the salinity constant???

 

[july865]

check it with a refractometer

 

[bozu]

i agree use a refracto kuz usually salinity raises due toi evaporation...........or try filling the hydro with distilled viniger for a minute and rinse.