Fleece Filter Roller and ATO Sensor

Steve2020 · Jul 11, 2022

I know this has been discussed in some treads a while ago but I figured I'd start another one because some recommended fixes to other reefers issues with ATO kicking in did not make sense to me. I will be installing a Fleece Roller Filter in the next few days and I have an ATO and I understand that when the level in my sock area rises, which is where my Fleece Roller Filter will be, my water level in my return section will drop kicking in the ATO adding RODI and lowering the salinity a small amount. The recommendations in the other Treads was to allow the water height in the filter area to rise just before the Filter Sensor detects and then set the ATO sensor to the level in the return section. This sounds great but now you will have the reverse problem over time to where the salinity will now increase over time because when the Roller Filter advances the water level in the return section will increase and due to evaporation over time salinity will increase a little. Either way you will have an increase or decrease in salinity unless I am missing something. The real question is how big of a change in salinity will you get? I have 255gal total water volume so what would be the total increase or decrease in salinity in PPT lets say for 1 gallon of RODI added or 1 Gallon of evaporation?

Steve2020 · Jul 11, 2022

Steve2020 said:
I know this has been discussed in some treads a while ago but I figured I'd start another one because some recommended fixes to other reefers issues with ATO kicking in did not make sense to me. I will be installing a Fleece Roller Filter in the next few days and I have an ATO and I understand that when the level in my sock area rises, which is where my Fleece Roller Filter will be, my water level in my return section will drop kicking in the ATO adding RODI and lowering the salinity a small amount. The recommendations in the other Treads was to allow the water height in the filter area to rise just before the Filter Sensor detects and then set the ATO sensor to the level in the return section. This sounds great but now you will have the reverse problem over time to where the salinity will now increase over time because when the Roller Filter advances the water level in the return section will increase and due to evaporation over time salinity will increase a little. Either way you will have an increase or decrease in salinity unless I am missing something. The real question is how big of a change in salinity will you get? I have 255gal total water volume so what would be the total increase or decrease in salinity in PPT lets say for 1 gallon of RODI added or 1 Gallon of evaporation?

I just located a salinity dilution calculator and for my system a .73gal change will only change salinity in PPT by 0.1PPT so I am probably looking at a .15 to .25 change in salinity up or down. I am assuming down is probably better than up for salinity. Does anyone see an issue with this amount of salinity change? I am not sure how many times a day the Fleece roller will advance. My salinity is kept at 34.9 to 35 PPT on a consistent basis.

A_Blind_Reefer · Jul 11, 2022

Not knowing your sump config, this may not be right, but typically your ato sensor/float/whatever will be in your return pump chamber. This area typically isn’t affected much level wise as it’s behind a set chamber divider. Now, if your running the new reefmat and program it to advance very infrequently then maybe it becomes an issue, depending on volume. If you program it to make smaller advances, in quicker succession, than it should not be an issue. If your running a regular, level switch operated roller, the diffference between a clogged filter triggering the advance, and the freshly advanced filter media, triggering the advance to stop, is minimal and should not have an effect on the return pump chamber.

Steve2020 · Jul 11, 2022

Zzyzx said:
Not knowing your sump config, this may not be right, but typically your ato sensor/float/whatever will be in your return pump chamber. This area typically isn’t affected much level wise as it’s behind a set chamber divider. Now, if your running the new reefmat and program it to advance very infrequently then maybe it becomes an issue, depending on volume. If you program it to make smaller advances, in quicker succession, than it should not be an issue. If your running a regular, level switch operated roller, the diffference between a clogged filter triggering the advance, and the freshly advanced filter media, triggering the advance to stop, is minimal and should not have an effect on the return pump chamber.

I took out my two 7" socks and plugged the holes and as the water level raised 2 inches above the sock plate which is approximatly were I will be placing the Fleece Filter Sensor, and my sock section is big, the level in my return section dropped from 8" to 5.5". Skimmer section of course stayed at 8.25" (adjustable baffle). 2.5" in my return equates to about 1.5-2gal so yes it does change as it should. If water level goes up in one section it must go down in another. ATO sensor is in the return section and turns on with about a pint of evaporation. Total water volume of my tank is 255gal.