DIY sumpoverflow question...

[srothenberg]

I'm thinking about installing a 20L sump under my 75 gallon reef to simply get more water in the system. My tank is not drilled, nor will I drill it. My only option seems to be a HOB overflow. However, these rely on siphons and in the event of a power failure, I could be screwed if it pumps my sump water overfilling my DT. I was thinking, instead relying on a siphon, why not run a second (smaller) pump in DT pushing the water down. This will eliminate the tank from overflowing unless the pump failing correct? Maybe I'm missing something, so give me your thoughts!

 

[vince-1961]

Two identical pumps, one from DT to sump, one from sump to DT. You get uneven flow rates because the one on bottom has head. So you end up pumping more water down than up.
Now, how did you plan to pump equal amounts in both directions?

 

[keebler]

Originally Posted by srothenberg
http:///forum/post/2813399
I'm thinking about installing a 20L sump under my 75 gallon reef to simply get more water in the system. My tank is not drilled, nor will I drill it. My only option seems to be a HOB overflow. However, these rely on siphons and in the event of a power failure, I could be screwed if it pumps my sump water overfilling my DT. I was thinking, instead relying on a siphon, why not run a second (smaller) pump in DT pushing the water down. This will eliminate the tank from overflowing unless the pump failing correct? Maybe I'm missing something, so give me your thoughts!
This may be confusing, so bear with me. It is easy to flood proof your system. The power goes out here very often for short periods of times and I have had no problems. I am using a U-tube style hob overflow and here is how they work. The pump from the sump pumps water to the tank and the overflow puts it back in the sump (duh!) In the case that the power goes out (ie. the pump fails) the overflow is designed to hold water in the tube. When the power comes back on, the water in the tube will start it up again. No problem. Correct me if i'm wrong but you thought that when the power went out the overflow would fail and when it comes back on you would have a flood? This shouldn't happen. Unless a fish jumps into the overflow and clogs the u-tube, I don't see how it can fail. Provided that you clean it regularly.

 

[srothenberg]

Originally Posted by vince-1961
http:///forum/post/2813629
Two identical pumps, one from DT to sump, one from sump to DT. You get uneven flow rates because the one on bottom has head. So you end up pumping more water down than up.
Now, how did you plan to pump equal amounts in both directions?
I never said I'd use equal pumps. I said I'd use a smaller pump in the DT with a larger pump down below. I'd have to do some math to figure out the head loss to keep from buying pumps and guessing and checking.
As far as how the sump and siphon works, I get it. I'm trying to take the HOB overflow with siphon out of the equation as they are prone to failure from what I read. A pump should perform significantly better then a siphon as it would automatically restart with power coming back on, even if it ran dry for 30 seconds while the sump pumped the tank back up.
Bottom line is, will this work? It's even cheaper then the eshoppes HOB overflow ($50) since a small pump is only around $20. I don't mind the extra pump in the tank as I'll relocate other stuff down below the tank.

 

[keebler]

Originally Posted by srothenberg
http:///forum/post/2813671
I never said I'd use equal pumps. I said I'd use a smaller pump in the DT with a larger pump down below. I'd have to do some math to figure out the head loss to keep from buying pumps and guessing and checking.
As far as how the sump and siphon works, I get it. I'm trying to take the HOB overflow with siphon out of the equation as they are prone to failure from what I read. A pump should perform significantly better then a siphon as it would automatically restart with power coming back on, even if it ran dry for 30 seconds while the sump pumped the tank back up.
Bottom line is, will this work? It's even cheaper then the eshoppes HOB overflow ($50) since a small pump is only around $20. I don't mind the extra pump in the tank as I'll relocate other stuff down below the tank.

The hob overflow will restart when the power comes back on.

 

[robertmathern]

I hate hate to tell you that wont work. You would have to match the flow going out and comming in to your tank exactly. So you would have to be constanly adjusting your pumps to match each other if you can adjust them. Because they will get alge in them and they will ware out over time. They will not ware at the same rate. And you would not know there is a problem intill you have water on your floor. The utube type are good. I would just install a float switch in the return section of your sump. That way if the overflow dose fail the water level in the return section will drop faster than the water level in the DT will rise. There for it will turn the pump off.

 

[prime311]

You'd risk more with 2 pumps then you would with a properly setup Utube overflow.

 

[normanknight]

Has anyone ever tried using two U tubes in one overflow. It would seem like this might work, but I am not sure if there would be too much flow, or if this would even be possible? It would be unlikely that both syphons would fail at the same time.