Salinity rising slightly

[airbrnebkr]

Over the past few days my salinity has been rising slightly from 1.023 to closer to 1.025. Thank tank temp has been at 78 for awhile with no changes. I know that salinity will fluctuate with temp changes but I have not seen any so I was wondering what may be causing this and if there is something I can do to prevent it.
Thanks,
Doug

 

[gbolton]

Are you experiencing any water evaporation? If you are be sure to top off with just fresh water.

 

[airbrnebkr]

I have had some very minor evaporation maybe 3/4 to 1 cup a day in the sump. I have been topping off with frsh water only. I am wondering if maybe I am just not clean my hydro (plastic kind) well enough or with the right stuff. Any suggestions

 

[mogurnda]

A cup a day seems pretty small. My little 20 goes through a quart a day. It may not be detectable as a change in water level before you see a change in specific gravity.

I have been using the same swinging-arm hydrometer for several years, and have only washed it with fresh water. To make sure it's accurate, be certain fill and empty it a few times, then give it a good rattle to dislodge bubbles from the arm.

Plastic hydrometers are notoriously inaccurate. It's a very good idea to have it calibrated using a refractometer or a hydrometer you know is accurate. Your LFS may be able to help you with this.

 

[airbrnebkr]

Thank you very much for the tips Dave.
Doug

 

[manfish]

I use one of those plastic hydrometers also. Give it a few taps with your finger to release air bubbles from lever. This works for me.