Sump question

[Nokinja]

I've been wondering this... how exactly do the siphon to the sump and the return pump level out so that the sump doesn't go dry or overflow because one is faster than the other? I've never understood that.

 

[lziarek]

I would assume they would both be the same gph? Actually this is a good question, more over how does one set up a sump or refugium? I am getting another 29 gallon and was thinking about setting up a refugium for my tank to grow pods/macro algea as food =).

 

[jr5018]

depending on if you have a pre drilled tank or you use an overflow ill go with overflow you have a basket that goes into tank and hangs over into another basket outside of tank in tank basket has slots in it going up and down about 1 to 2 inches long outside basket has hose going to sump. adjust inside basket up or down to increase or decrease water flow into outside basket and eventually sump. now place a pump in sump (should already be there) with a line running back to tank. start suction from internal basket to external basket using a "U" tube and a small tube as soon as sump fills up to cover pump turn pump on adjust internal basket accordingly. And there you go. Hope this helps any questions just ask.

 

[fishfreek]

The overflow uses a siphon to pull the water out of the tank and down the plumbing into the sump. Hang on style overflows use what is called a "U" or "J" tube. This is because of the shape. The tank side of the overflow has "fingers" that strain the water (very coarse items only), these fingers also are adjustable so you can set the water level you want the tank to maintain. Once the siphon is created the water will be pulled up and over the side of the tank via the "U/J" tube. It will then flow down the plumbing into your sump. Your sump pump then pumps water back up into the tank.

In theory the pump is consistently trying to overflow the tank while the overflow is trying to drain the tank so assuming your overflow can handle equal to greater capacity than the pump can pump you will have equilibrium.

The above is from my 'Sumps Explained" article. The jist is that the overflow will only drain the tank to the point that water no longer flows into the in tank portion of the overflow box. The pump will always be trying to overflill the tank and the overflow will always try to drain the tank to the water level I just explained. Since the overflow can only drain water as fast as the pump is putting it into the tank as long as you dont size the pump larger than the overflows rated capacity you wont have problems balancing anything out.

 

[Nokinja]

Here's another stupid question... What's to stop the pump from slowing down overtime and causing the overflow to fill the sump before the pump can drain it? I guess i'm hard headed. I dont get it.

 

[fishfreek]

You dont run the sump at 100% cpacity anyway. The overflow will only drain water out of the tank as fast as the pump can put water in. So if the flow from the pump slows then the overflow will slow aswell. If you turn the pump off totally the entire volume of the tank does not drain into the sump. Only a small amount will drain into the sump until the water level is below the top of the overflow box that sits inside the tank. If at all possible I would suggest trying to find someone with a sump/overflow setup that you could see in person.

Seeing one in person will clear up alot of your confusion.

 

[SquishyFish]

Ask at your lfs if they have one set up on their display tanks...

 

[Brad]

Think of it this way...

If you have a garden hose and you fill up a bucket until is starts to overflow....then you turn up the hose more...the bucket doesn't get any MORE full, it just overflows more, faster.

That's crudely how the overflow siphon works. No matter what speed you pump water in, the overflow rate increases/decreases automatically to match.

This works only to the point of maximum overflow rate through the siphon. If you surpass that, the overflow cannot keep up with the pump and the aquarium overflows. That is why you put a valve on the return pump...you want to be able to turn the pump DOWN if you need to.

 

[Nokinja]

Okay, I wasn't thinking about the overflow box for some reason. I understand it now. If the overflow can handle more GPH that the pump can put into the tank it balances. Forsome reason I was forgetting about the overflow. Ignore me.

 

[indy]

I'm sorry, did you say something? JK

It is a lot easier to understand once you've seen it in action.

 

[saberry]

I agree. I'm considering one now to help get some of the gear out of my tank. I was confused until I went and saw a couple at the lfs. It was a lot clearer once I was able to look at it and trace out the flow myself.

 

[methuse]

Well to answer the question of why doesn't the sump just overflow.....On my sump there are two large valves that you can open and close entirely or partially. The gph flow of the overflow with the sump valves wide open for exceeds the ~2000gph that the pumps provide. So what I do is close the valves partly until the water level in the overflow boxes is just slightly below the teeth at the top of the overflow box. What prevents the pumps from just overflowing the tank you may ask, an emergency high volume line at the top of the overflow box that leads directly down to the sump. What happens when the power goes out you may ask....well first the pumps go off... then the overflow box empties into the sump, then the tank itself back-siphons through the powerheads into the sump until the water level in the tanks drops below the powerheads. The tank is 180gallon and the sump is 40gallon. There are about 20gallons of bioballs in the sump being soaked by the returns after the water is pre-filtered with filter floss.