Salinity in Display tank increasing with ATO in Return section of the sump

[Hunter90 HD]

Good afternoon reefers,

I have a quick question, so i have a Reefer 425xl and i am using the ATO reservoir that came with the tank using the float switch for ATO.

The last few weeks when i been doing water changes, i have noticed the salinity in the display is always 0.02 higher each week so i would start from 1.026 then end up at 1.28 at the end of the week.

My ATO works okay and i top it up every 3-4 days and keeps the level in my return pump section of the sump at a constant level.

But my salinity in my display and sump always increases.

Am i doing something wrong?

From my understanding the ATO is in the return pump section and you dont need a sensor in the main display or have i misinterpreted?

Any advise would be great, thanks!

Lee

 

[pecan2phat]

If you're replacing evaporation with RO freshwater to the same set water level, increasing salinity does not make sense.
Need others to chime in.

 

[pecan2phat]

I have 3 tanks with ATOs and 2 of them have the sensor and makeup water going into the return pump section and have not experienced what you are experiencing.

 

[Hunter90 HD]

I have 3 tanks with ATOs and 2 of them have the sensor and makeup water going into the return pump section and have not experienced what you are experiencing.

Yeah its strange, ive read alot of reefers dont bother with the float switch and the ATO reservoir that comes with the Red Sea Reefers and replaces it with a Tunze ATO for example.

Cant explain it looks like the water in the main display is evaporating i did notice the weir level dropped too

 

[pecan2phat]

Then I would say the RS float mechanism is not accurate and fluctuates. Replacing with a Tunze sounds good.