Can't Keep Salinity!!

[VioletGoby]

Okay, I'm a novice, used to have a Freshwater for some time, and thought I'd get some more "exotic" fish. Found a fish that I wanted to "spotlight" and chose the Violet Goby.

After research I found that they prefer Brackish, wanting to provide the best for the fish, I decided I'd try a Brackish Tank. After more research I didn't think it wouldn't be too much more difficult.

To explain my setup,

44G Corner Tank, 200W Heater, H.O.T. Magnum 250 running with ProCarb, a Air Pump with two air blocks, a bubble curtain, and a bubble-action figure.

For Decorations, I have some Aponogetons and Java Ferns, a foot long piece of Drift Wood.

The tank has been cycled and other than the salinity has been stable as far as any pH and hardness.

Currently it is home to 4 Marble Sailfin Mollies, 3 Platinum Lyretail Mollies, some Fancy and Tuxedo Guppies, a dozen Ghost Shrimp, and some intruding snails.

I'll be keeping the Mollies in the tank. The Ghost Shrimp are a bit of a cleanup crew and food for the Violet Goby (when I get them), I plan on getting some Olive Nerite's for algea clean up. The Guppies will be moved over to a fresh water tank and continued to be used as feeders (were put in the tank to help cycle and just haven't taken them out yet).



Now, the problem...
I just cleaned my tank (clean once a week, 10%, only vacuming 1/3rd the gravel), and added salt to a 1.010. That was Last night about 9pm. I just checked now, and the Salinity is at 1.006 (it is currently 6:30pm). Now, I have another Hydrometer, and it agrees (currently using a glass floating hydrometer).

Is this normal to be loosing this much salt? or am I doing something wrong?

Any help would be appreciated!!!

[Fishnewb1]

Im not brackish but i know a lil about it...

how long has your tank been cycled??
Have you added any fresh water to the tank since you started (from getting new fish when dumping the bag in if you prefer that method)..if you did that is a very likely reason..
have you been doing water changes??

but otherwise usually you have to add fresh water too it from evaporation...

make sure all the bubbles are out of your hydrometer!!!!

adam

[VioletGoby]

I do apologize as it seems I goofed, it is the SG that is screwed up, not salinity, minor differentiation in terms i guess

The Tank has been setup for over two months, Cycled for over a month (one week after setting up I added 7 Mollies to cycle it, tests show it is at good levels on all scales right now)

I have added declorinated freshwater to the tank only to compensate for evaporation. I never add the water from a bag when adding fish, always scoop the fish out after a couple hours of the bag acclimating and pitch the LFS water.

I run a 10% (5Gal) water change once a week.

For the FW added for evap, I was in the understanding that since the water evap'ed, the salt was still left behind, so that shouldn't affect the SG that much.

The one hydrometer I use is a glass floating tube, before reading it a dunk it to make srue all debre and bubbles are off. The Marineland Plastic Hydrometer I use is also rinsed and dunked to make sure of the same.