Water level in sump - What am I missing?

[Moeshi]

I've been reefing for a little over a year and never used a sump.
Just recently I decided to install one under one of my tanks because I had the space and equipment needed.

Clearly I'm missing something obvious when I'm adjusting the water level...
I have a series of observations with questions I'd love to sort out.

1) When I stick my arm in the tank, the water level rises. This water goes down the overflow and into the sump. From here the water level in the return chamber rises permanently by the amount of water equal to the size of my arm.
Does this mean I have to adjust my ATO (sitting in the last chamber) to the new water level, every time i displace water when adding new fish/move stuff in the DT?

2) When not dialed down my return pump empties the return section faster than water can replenish the chamber. However my overflow is capable of handling the extra water just fine, it just doesn't make it down to the last chamber in time before the pump runs dry.
Does this mean the sump is too small for the power of the pump, or does it mean I should add more water to the loop to make up for those crucial seconds before water starts to flood the return chamber?

3) When I shut off my return pump the water in the last two chambers levels out completely. When I turn the power back on the water level in the last chambers seems totally unpredictable regardless of how long I leave it on.
Should I avoid shutting off the return pump all together when working with the sump, or is there something I'm missing?


If you made it this far, thanks for reading through all of this.

I hope someone can shed some light on this and help out a complete sump newbie.

Kind regards,
M

 

[scelona]

1.) The level in the sump will return back to the original level if given a little time. Think about it like this: after you stick your arm in, there is a build up of water in the return section of the sump and less water elsewhere. This means that there will be a decrease in the rate at which the return section is refilled so your system will reach equilibrium if given some time. Shouldnt take long.

2.) If your return section is running dry then you need more water in your system. If it needs so much water that your sump overflows when your return pump is off, then your sump is too small or you are getting back flow from your display tank or your design is a little off.

3.) This is the same issue as number 1, the system will reach an equilibrium if given some time.

Maybe post your sump design so we can get a better understanding of your system. Maybe you did something funky without realizing it.

 

[Hunter1998]

It's also possible that your return pump can't keep up with how much your overflow/overflows are draining. If you have a gate valve on your overflow line dial it back a little.

 

[Hunter1998]

Same thing as the above post haha, my bad I didn't read through it.

 

[TatorTaco]

Is the issue that DT and Sump never reach an equilibrium - like once the water is pushed to the sump, it stays in the sump? I have a similar issue, but after about....2-5 minutes the water level should balance out. I also experience this during water changes, but it takes longer due to the amount of water.

 

[billdogg]

It's also possible that your return pump can't keep up with how much your overflow/overflows are draining. If you have a gate valve on your overflow line dial it back a little.

That just isn't possible. The overflow from the DT can only be as much as the return pump can pump up there. It is possible to have too much return flow from the sump and then overwhelm the drain, but that does not seem to be the problem.

 

[Cymonous]

I'm sorry, but just about everyone is wrong except billdogg.

If your pump is sending water back too quickly, you will need to add a valve to the line from the pump going to the tank (the return) and dial it down.

We need some kind of drawing showing how your sump is setup. Is your ATO actually in the chamber with your return pump? It should be if it is not.

 

[Deleted member 336650]

1) When I stick my arm in the tank, the water level rises. This water goes down the overflow and into the sump. From here the water level in the return chamber rises permanently by the amount of water equal to the size of my arm.
Does this mean I have to adjust my ATO (sitting in the last chamber) to the new water level, every time i displace water when adding new fish/move stuff in the DT?

2) When not dialed down my return pump empties the return section faster than water can replenish the chamber. However my overflow is capable of handling the extra water just fine, it just doesn't make it down to the last chamber in time before the pump runs dry.
Does this mean the sump is too small for the power of the pump, or does it mean I should add more water to the loop to make up for those crucial seconds before water starts to flood the return chamber?

3) When I shut off my return pump the water in the last two chambers levels out completely. When I turn the power back on the water level in the last chambers seems totally unpredictable regardless of how long I leave it on.
Should I avoid shutting off the return pump all together when working with the sump, or is there something I'm missing

1. Don't worry about changing the ATO, water level will adjust on its own. If you add something large permanently like sand/rocks, the displaced water will have to evaporate. If you add a lot, you might have to adjust salinity.
2. Just dial the return down. From what I have read, it may reduce the life of the pump. Mine is at about 50%. Or you could get a smaller return pump.
3. I never turn off my return.

All just my opinion.

 

[ryeguyy84]

1. Don't worry about changing the ATO, water level will adjust on its own. If you add something large permanently like sand/rocks, the displaced water will have to evaporate. If you add a lot, you might have to adjust salinity.

2. Just dial the return down. From what I have read, it may reduce the life of the pump. Mine is at about 50%. Or you could get a smaller return pump.

3. I never turn off my return.



All just my opinion.

To dial down the return tee the line and have a portion go back into the sump. Valve the line running to the sump to adjust how much goes back in the sump. Much easier on the pump.

Or have it run a reactor.

 

[ca1ore]

2) When not dialed down my return pump empties the return section faster than water can replenish the chamber. However my overflow is capable of handling the extra water just fine, it just doesn't make it down to the last chamber in time before the pump runs dry.
Does this mean the sump is too small for the power of the pump, or does it mean I should add more water to the loop to make up for those crucial seconds before water starts to flood the return chamber?

Not sure I'm entirely following #1 and #3 (it's late and I'm tired) but #2 is easy. Given a fixed linear length of overflow, more flow means the water rises slightly before the weir (or any baffles in the sump) in order that more water moves over it. Consequently, a system will hold slightly more total water at say 1,000 gph through the sump than it will at 500 gph. Depending upon the size/volume of the final return chamber, you may well see the levels drop as you increase pump output. This drop will be 'permanent' until you adjust the pump back down. Nothing wrong with it though. If you want the higher flow, you just add some water to the system one time to compensate; then let your ATO di its job.

 

[Moeshi]

Here's the basic design of the sump. Notice it's square due to limited space.


I don't know exactly what I did, but the water level has leveled out in the return chamber now as you said. I guess patience was the key. It took close to 5 hours. However the pump is dialed down to around 10%, which leads me to suspect that my custom overflow is faulty. I will try and take it apart today and report back any improvements on flow. Clearly it's restricting the flow.

The slow flow throughout the sump doesn't bother me, but I wonder if it affects the effectiveness of the skimmer. It appears to be pulling gunk as usual without any noticeable issues.
Can the flow through the sump be too slow? The sump is already being populated with critters, but the bubble trap is so gentle I wonder if the pods will ever make it to the DT.

Thank you for all the help and advice. I appreciate it.

 

[Cymonous]

Unless you have a million weirs in your sump, the sump is not going to be the cause of slow flow. You either have an incorrectly setup overflow/drain piping or your pump is just way too strong. What return pump are you using? Can you take pictures of your overflow, plumbing and the sump?

 

[JammyBirch]

Sounds like your drain is plugged and restricting flow or you're air locked somewhere. My sump is very similar to yours I run the fuge parallel to the skimmer and return chambers though. My system air locks every time I shut the return off ad the drain lines empty. I toggle the ball valve on the drain and it breaks the air out.

Maybe you have a similar problem. Pictures would be great.

 

[Moeshi]

I got around to take the whole thing apart last evening. A what do you know. A one inch pvc piece had made it through into the plumbing and was stuck at one of the elbows. I have no idea what-so-ever how it got there. I haven't even worked with that size pipes either. Now everything is working as intended!

Thank you all for much for the helpful replies. Now the overflow is pushing so much water, my next thread will be about silencing the gurgling noises from the pipes as well as the return pump vibrations. This is going to be great.