Help Explain Sump/DT Level Relationship:

[bevo5]

I’m a bit confused as to how the sump and DT water levels are related. I thought it was as simple as the DT would always stay the same level as my overflow, while the sump level would fall due to evaporation. I just set up my 200g with about 40g in the sump and I’m having a hard time keeping it all perfectly level.

I’m judging the DT water level with my emergency drain. I want to keep it at a very slight trickle so the water level is right up to the edge.

I got the sump right where i want it and marked it with a piece of tape. Came back later that night to top off and I poured water into the sump to get it to where I want it. This ended up somehow pushing my DT level a bit higher as the emergency started to get a good stream of water in.

Also - when I don’t top off for a while I notice the water level around the emergency drain is lower.

The entire time, however, my pump is completely submerged in the sump. I can’t wrap my head around how the DT could be any bit higher or lower when the pump is steadily pushing the same amount of water nonstop.

What am I missing here?

My plan is to put the ATO in the return part of the sump and just keep that level as it’s the lowest baffle.

I always thought once I got the sump level stable the DT and overflow would stay level. As it is now I’m having to constantly adjust my gate valve to keep everything where I want it.

Thanks.

 

[TheEngineer]

This most likely has to do with the head pressure on the pump in your sump. The higher the water level in the sump the less head pressure and therefore the more water it can push to the DT. An ATO will help you tune the drain rate so you don't see so much fluctuation.

 

[bevo5]

Interesting - such a small change in the water level in the sump will actually raise or lower the pump speed. The temporary increase in water pushed up fills up the overflow just a bit more I guess....

My ATO is currently hooked up to the tank holding off of the livestock while this one cycles. SO once I move stuff over I will hook it up. For now I guess it doesn't really matter as long as the pump has enough water in it so it doesn't run dry somehow.

 

[TheEngineer]

Yup. PHYSICS! haha

 

[bevo5]

Hey I got an A in physics my freshman year in college. I actually got a D, but the bell curve turned it into an A because of all the other idiot communications majors that were in way over their head just like me.

 

[TheEngineer]

Ha! The curve helped a lot when the soon-to-be business majors were still in my engineering classes freshman year. Less help after the first term ended and they all transferred to the business school.