Auto Water Change and Maintaining Sump Water Level

[ubiq]

I'll be setting up a DOS to do auto water changes in my 100. If I set it to change 10% weekly, unless inflow and outflow are simultaneous, the outflow will lower the sump level to the point where it triggers my ATO and roller sensors. If simultaneous, I'm not really changing 10% because the outflow is partially depleting the "new" water as it comes in. Has anyone dealt with this?

 

[JGT]

If you spread out where the outflow and inflow is happening in the sump you should be fine. There was a study done (somewhere on R2R) that showed this method was just as effective as outflowing first and then inflowing.

 

[Woodneers]

A dos set up for auto water changes will add and remove water at the same time. Add to the pump chamber and remove from an upstream chamber.

 

[Erick Armanii]

Everyone does them simultaneously which prevents the ato from kicking in..

The dos is limited onto how much water it can do in 24hrs

 

[bobnicaragua]

My ato only runs every 3 hours. Daily automated water changes happen when ato is inactive. I only pump out about 1/4 of the old salt water before new salt water starts pumping in so the sump level doesn’t drop too much.

 

[Brett S]

I think there are really two options for this. One is to just do them simultaneously and not worry about it. As mentioned above, careful placement of your lines can help mitigate this problem. I have my new water delivered into the return pump chamber in my sump and the old water removed from the chamber in the sump where the tank drains. Since my AWC runs 24/7 it only changes 66ml every 10 minutes, so it’s very unlikely that any of the new water is making it through the DT and being removed with the old water.

If you don’t want your ATO running continuously and you want to change a lot of water at once over a short time period then you are more likely to run into an issue where you are removing some new water with the old water. In that case you can drain first, then add and simply have the apex turn off your ATO and rollermat while the AWC happens, then turn them back on when it’s complete. If you need help with the programming for this, let us know.

 

[BZOFIQ]

If simultaneous, I'm not really changing 10% because the outflow is partially depleting the "new" water as it comes in. Has anyone dealt with this?

This is a non-issue really. You're overthinking it. The numbers between either scenario are fractionally different.