Sump Question

[werkkrew]

I have a general question about the "equilibrium" of sump filter systems.

I am basically afraid to leave my setup running unattended for any amount of time because I lack a full understanding of what is going on.


If I use ball valves to carefully calibrate the flow, in and out of my sump, so that everything looks ok - the overflow seems to match the pump output - what happens if / when the overflow or pump output become SLIGHTLY mismathed, perhaps due to buildup on the pump inlet, or a minor blockage in the overflow tube?

It seems to me that inevitably either:

Your pump will wind up running dry because you dont have enough overflow.

Your sump could almost overflow due to the pump running at a lower rate then your overflow.


Now obviously you should have a sump which can handle the maximum amount of excess overflow without overflowing, and your tank should be able to handle your pump overpumping into it as much as your pump section holds, but I am still wondering if people have to constantly readjust their ball valves as system conditions change or if there is something I am simply missing.



Also, just as a side question, in most of what I am looking at photo wise in peoples DIY sumps, I dont see the use of many float switches to turn off the pump in the event it runs dry.

Am I being overly paranoid? If my tank or sump overflowed, being on the second floor of an apartment I am being ultra cautious.

[drillsar]

Well you could use what they call PVC Check Valves they will make water flow in one direction. For the Overflow I would highly recommend Lifereef there the best, alot of overflows are just designed bad and overflowing is a huge possibility. Usually you will overflow if your flow is wrong in either to much or to little.

[woodycb]

Your overflow will drain faster or slower depending on how powerful your pump is. It will find a happy medium, if your pump is too powerful you can adjust that with a valve on it. Do not adjust the flow to the sump only the flow back to the tank. I have a 600gph overflow on my tank and a mak40 return pump. The pump is way more powerful than what my overflow can handle so I had to slow my flow down with a valve. You should try and run your sump half full so if you do lose power the water draining to the sump wil not overflow it. To help stop to much water from getting back into the sump due to a power failure you can use a check valve on the return line. The return line will create a siphon once the pump has lost power or turned off and drain the tank to the sump until the outlet is not under water in the main tank anymore. Once the water gets below the teeth of the overflow box it will not drain to the sump anymore. Thats what will happen in the event of a power failure or you turn the pump off for maintenance.

[PaulCom]

The tank will drain only until the water level gets below the slots in the overflow. You should be able to easily determine what the volume of water is above the slot in normal conditions and make sure your sump has the capacity to take that much more extra water in case of problems.

If your tank is drilled, you shouldn't have much of a problem with your sump/return pump running dry - if problems arise, as long as the water level gets back above the overflow water should continue down into the sump. If you have an over-the-top overflow - I would think that if you got close to your sump running dry you would have problems with your display tank overflowing first. I used an over-the-top overflow for four years and never had a problem - but then I always checked the u-tube and drain line for restrictions when I did water changes to make sure they were clear.