Salinity staying same ans water level dropping

[merfury1989]

So recently I noticed that my water level is dropping and salinity staying same, if I let my ATO do its thing, it will top up when level drop, but by doing that it's reducing salinity.
So I had close off ATO. Now water level is dropping and salinity staying same, what could be reason here.

There are no leaks anywhere

Filter I am using is sock, that's all.

 

[Daniel@R2R Verified Admin]

Sure sounds like a leak. If water level drops but salinity isn't increasing, water is being removed somehow

 

[merfury1989]

Sure sounds like a leak. If water level drops but salinity isn't increasing, water is being removed somehow

That's the weird bit, there are no leaks anywhere, don't see water coming out of all angles of the tank.

 

[Garf]

How are you measuring salinity? And how much has the level actually dropped? You’ll struggle to measure just a few % of salinity change, for example.

 

[merfury1989]

I am using red sea refractometer

The drop of water level is all the way from top of the return chamber to just below half (Waterbox mini Peninsula 25). The chamber height Is 400mm (
15.7 inch), so a drop of 200mm (7.5 inch) and no salinity increase

 

[BaliReefBox]

chamber size (80x118x400). so you are losing approx 1.9 ltr without a change in SG. I know with my efractometer to try and measure acurately and consistently is hard. I cal mine every time i use it. maybe try a cal and see it its the same

 

[Garf]

I am using red sea refractometer

The drop of water level is all the way from top of the return chamber to just below half (Waterbox mini Peninsula 25). The chamber height Is 400mm (
15.7 inch), so a drop of 200mm (7.5 inch) and no salinity increase

It’s normal to lose 1 to 2% a day in evaporation. Does the loss fall in that ballpark?

 

[merfury1989]

1 to 2% loss is ok, but normally it increased salinity and I topped it up with ATO.

This time drop is same, but no change in salinity.

What is cal?

 

[workhz]

Calibrate. Chances are it’s just a measurement issue.

 

[merfury1989]

Calibrate. Chances are it’s just a measurement issue.

Ah I already done that, it shows 35ppm at the top, and 35ppm at half way

 

[BaliReefBox]

Are you using a known testing / calibration fluid /agent that is set at 35..salifert make one or there are threads on here to make your own. If you are testing the return chamber when it is full and then when it is half full at a 90 litre capacity and losong 2 litre to evap it should i would think change the sg.. make it go up slightly.

 

[Garf]

Ah I already done that, it shows 35ppm at the top, and 35ppm at half way

Some light reading for you;

http://reefkeeping.com/issues/2006-12/rhf/

 

[Randy Holmes-Farley Verified Community Expert]

Skimmers remove salt water, but otherwise, unless you are removing water, there is no mechanism for salinity to decline in a reef aquarium at fixed water level.

 

[workhz]

Skimmers remove salt water, but otherwise, unless you are removing water, there is no mechanism for salinity to decline in a reef aquarium at fixed water level.

No mechanism to decline but a mechanism to measure lower … higher temps?

 

[Randy Holmes-Farley Verified Community Expert]

No mechanism to decline but a mechanism to measure lower … higher temps?

Yes, if you are using a device that is sensitive to temperature and is not properly correcting for it, then the measurements will move around as temperature changes.

To be clear, however, salinity itself does not ever change with temperature.

 

[dadnjesse]

Skimmers remove salt water, but otherwise, unless you are removing water, there is no mechanism for salinity to decline in a reef aquarium at fixed water level.

That's what I was going to say. Are you using a Skimmer and are you getting a lot of skimate.