Low salinity: again! what am I doing wrong

[swiss1939]

No, I haven’t urned it off. Honestly didn’t think I needed to if I was only pulling water from the display tank. The Red Sea reefer comes with instructions on how to put it together but not how to do proper water changes! I even tried watching YouTube videos on how to do water changes with a sump and ATO! Lol this is my first all-in-one tank so still getting the hang of this.

I feel like an idiot, that’s probably exactly what the issue is Lol! Thank you

Yes if you are leaving your return pump on while doing water changes, your water level in the return section of the sump will lower because the total system volume is lower. This is how the ATO works through gravity. Set up your sump so the water level when full is just above the float closed height (since you can't raise or lower the stock red sea float much). I just grabbed the float and lifted it lightly until i felt resistance and made a mental note of the float height compared to the bracket it is attached to. This is your ATO float closed height. So as I was saying, set up your sump so the water level in the return when all pumps are on and equipment are in the tank so that the water is jus above the float closed height. Then fill your ATO and open the ATO float valve and leave it for a week. Don't make changes to the overflow/return flow height in the DT weir because those changes will either drastically raise the return pump section water level or drastically lower it. Then confirm after a week your salinity is the same (as long as you kept the ATO resevoir topped off the whole time). And like I said previously, if you are fiddling with your overflow valve to get the trickle to quiet down, close the ato float valve before doing it.

 

[BeMoto]

If you only take water from the DT the ATO shouldnt dump water into the system. Make sure all the screws are tight on the float valve. Mine came with the adjustable style that has a hinge on it. I replace it right away with a Tunze because i didnt like the float style ATO.


Edit: Your return pump has to be off during the water change if you dont turn the ATO valve off.

 

[x2uranium]

I have and seen a bunch of times a lot of wet skimming and dumping will also bring your level way down if your not paying attention

 

[Daddy-o]

I would often forget to turn my ATO pump off when doing water changes so I plugged a small light into the ATO plug. Now when the pump is on, the light is on. It has saved me a couple of times. When I see the light is on for an extended time, I know there is an issue or the ATO is empty.
Cheers! Mark

 

[JAMreef]

Yes if you are leaving your return pump on while doing water changes, your water level in the return section of the sump will lower because the total system volume is lower. This is how the ATO works through gravity. Set up your sump so the water level when full is just above the float closed height (since you can't raise or lower the stock red sea float much). I just grabbed the float and lifted it lightly until i felt resistance and made a mental note of the float height compared to the bracket it is attached to. This is your ATO float closed height. So as I was saying, set up your sump so the water level in the return when all pumps are on and equipment are in the tank so that the water is jus above the float closed height. Then fill your ATO and open the ATO float valve and leave it for a week. Don't make changes to the overflow/return flow height in the DT weir because those changes will either drastically raise the return pump section water level or drastically lower it. Then confirm after a week your salinity is the same (as long as you kept the ATO resevoir topped off the whole time). And like I said previously, if you are fiddling with your overflow valve to get the trickle to quiet down, close the ato float valve before doing it.

I was messing with the overflow the other day. I didn’t even consider it would mess with the ATO. Thank you

 

[JAMreef]

Thanks for everyone’s responses. Very humbling experience getting all these responses. Thanks again!

 

[swiss1939]

I was messing with the overflow the other day. I didn’t even consider it would mess with the ATO. Thank you

Turn off your ATO and play with the overflow levels. You will see when you raise the water level in the wier in your DT (by slightly closing the overflow valve on the right), the water level will lower in the return pump section of sump. Vice versa, lowering the water level in the wier raises the water level in the return pump section. This is also why when you do a power out test, the return pump section of the sump overflows and probably equalizes with the water level of the rest of the sump... all the water in the wier flushes back down into the sump.

What you are trying to do with the overflow valve is to balance out the return pump flow with the overflow flow so they are equal speed/volume. This makes it quiet by preventing water from trickling down a partially empty overflow tube or emergency overflow tube, and the water height in the wier should be about 1-1.5 inches below the grates in the wier when set properly on these red sea tanks. Then the ATO takes care of evaporation as the water level in the return pump section is what fluctuates due to evaporation. Leaving everything constant, only the return pump level and ATO resevoir level fluctuate.