sump drain problem

[bioxide]

just got through building my sump and ran a test run on it last night, I have a dual 700gph weir (dual U tubes feeding dual 1" drains) from 100gal display to approx 30gal (at normal level) split style sump, the problem I'm having is my weir box has dual 1 in drains but the dual U tubes appear to be 3/4" and the turnover doesn't appear to be as high as it should. I have a mag 18 from 1" to 3/4 closed loop for return (went with extra power because of the span of pipe and higher head and dual returns) and I have to keep the ball valve wide open coming to the fuge and valve almost closed from the mag18 to display. What should I do, it seems the whole problem I'm having is the wier, larger U tubes? maybe a 3rd or 4th U tube? Help appreciated....

 

[bimmerzs]

You are correct in that your drain is not keeping up. The Mag 18 sounds like it is too strong for your application. You should not try to get "massive" flow to your tank with your return pump, use PH's or a closed loop for that. I would be willing to bet money that if you dropped down to a Mag 7 or possibly a Mag9.5, your problems would disappear. You could then use the Mag 18 for an awesome closed loop setup. Also keep in mind that the Mag18 will add a ton of heat to your tank, hope ya got a chiller. I thought a 1" line only would drain 600gph and I don't think having 2 line's equals 1200gph, but could be wrong.

**edit** If you keep it like that, the chances of overflowing your tank is very high. At least that's what happened to me. :wink:
Cheers!

 

[bioxide]

thanks for the reply. I knew the mag18 was too much (left over from another project) and was already thinking of dropping to a mag9.5 because of the heat but I have a ball valve for throttling the flow from the return pump to control overflow. But the issue is when I get the return equalled to the intake its just barely moving any water. the water flowing into the sump just isn't moving in like it should, if I shut the return pump off it take about 3-4 min before the sump water level raises 1 gal . I was thinking maybe of making some of those gurgle things for my downpipes in the overflow and the tube from the top might help the water movement but not sure.

and as far as my overflow it was supposed to be a 1400gph overflow, so I just assumed 700gph per pipe :?: , I figured about 600gph per pipe was probably more resonable.

 

[K-PO]

Have you checked to make sure that air hasn't gathered in the U-tubes? That can really slow down an overflow.

 

[bioxide]

I have noticed that problem, how do you get the air out?? And could I have the same problem with the down pipes??

 

[K-PO]

First, you need to start the siphon by inserting some airline tubing into the u-tubes. When the return pump is on and the water level has risen above the overflow box, suck the air out of the u-tubes and the siphon will start. If air gets trapped in the peak of the tubes after the siphon is started, grab the top of the tube and pull it up and drop it down (rather firmly) making sure that both ends of the u-tube remain submerged. This will break the trapped air bubble up and allow it to flow through. I don't think that it is possible for air to get trapped in the down pipes. Hope this helps.

 

[bioxide]

i can get the siphon started but the air bubble in the U tubes seems to be on the back side instead of the peak. and on the downpipes I was wondering if there is a way to make it drain faster? like building 1 of those hoffer gurgle buster (and to also make it quieter and reduce air bubbles in the sump)

also I have noticed that between the front part of the overflow(where water comes in from display) to the back part (where it goes to downpipe) can't equalize. Like my U tubes can't keep up with the downpipes, maybe?

 

[bimmerzs]

@bioxide wrote:

You need to get the air bubble completely out of the U-Tubes

Same thing- get the airbubble out

I know you hate to hear it but you will probably have to change the Mag18, if you are still fighting it after getting the air bubbles out of the U-tubes then you know what ya gotta do.

Cheers!

Sorry!

 

[K-PO]

I find that on the dual u-tube overflows, lack of gph is the main culprit for air bubble accumulation. Try turning up the return gph and then try to get the air bubbles out. I know this because I have had a dual u-tube overflow stop using one u-tube because of lack of return gph. Feel free to call me in regard to this matter (# listed in my profile). I have too much experience with this type of overflow.

 

[bioxide]

turn up the return pump? so I guess slowly turn it up and try to get the air out at the same time? i'l give it a try later this week.
thanks again!

 

[casey]

if the peice of pvc that is glued into the bulkhead of the hob overflow is not the right height it will cause the u tube to drain it is possible that this balance is out of wack.the pipe has to be as high as you need the water in the front of the box and no higher(as far as getting everything to flow better with less noise and bubbles in sump that would require that you put another drain on side of box and use a gate valve on primary drains)do not attempt to regulate the flow of your drains without at least one back up drain on the side(i prefer 2 backups if you have alot of flow)

 

[melev]

The reason you want more flow is to flush the trapped airbubbles in the U-tube completely out. When you set it up, you need to have it full of water and no air, and then from that point forward just verify visually that no air is gathering at the apex.

http://www.melevsreef.com/prime_overflow.html

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[casey]

well said by marc