Problems getting strong siphon from overflow.

[Invertical]

can't seem to get a good siphon from my internal box to my outside box..I have a 1" pvc tube that barely siphons at all, and I don't know if it's the angle or not....I have a rubber hose that barely siphons as well 3/4" ID. and the ones that seem to siphon the best, but not nearly enough water are the 2 clear 5/8" ID hoses...if I put the 3/4" ID hose in with the two 5/8" ID hoses it siphons decent, but not near what I feel just the 3/4" ID hose should be doing along....also does the PVC tube have a bad shape for a siphon tube? any help would be great!!! I can't think of a reason why there would be poor siphon....I mean it could fill up a quart jar in about a half an hour...with the pump on....I have to turn the pump waaaaay back in order for the pump chamber not to run dry.....please help i'm getting sick and tired of this overflow!!!

 

[Frankie]

Could you post some pictures of your setup?
http://www.reefsanctuary.com/forums/meet-greet-forum/8959-uploading-photos-rs.html

 

[Invertical]

tubes i've tried...with very very slow siphon
http://www.reefsanctuary.com/photopost/showphoto.php/photo/15386/cat/508

pic. of my external box...tubes go below drain.
http://www.reefsanctuary.com/photopost/showphoto.php/photo/15384/cat/508

picture of internal and external boxes....water is low since i'm working on it
http://www.reefsanctuary.com/photopost/showphoto.php/photo/15385/cat/508

any suggestions?

 

[cbrownfish]

So what is the problem exactly? Is your return pump sending water to the display quicker than it can drain?

1. It is common to have to throttle a return pump back to a reasonable level, so you don't push to much water. If you are depending on the return for flow, then this is a mistake. Either create a separate closed loop or add powerheads.

2. The hoses you are using have a very small diameter and will only handle a small amount of water. You need a bigger tube, assuming the OFB will handle more water. Most overflow boxes use a standard U-tube which is a 1" tube I believe. See here --

Most overflow boxes are designed to handle X amount (300, 400, 500, 600, 700, etc.) of flow as a maximum. The OFB may be able to handle more but you need a bigger diameter tube. Remember this is a gravity drain, so you are only going to get a moderate amount of drainage in GPH. In general, a 1" PVC drain is only going to handle 5-700 GPH as a best case scenario. If your return pump can push 900 GPH, then it will out pace your OFB unless you throttle it back.

 

[Frankie]

Try building one of these and see if that helps any Hofer Gurgle Buster

 

[Invertical]

So what is the problem exactly? Is your return pump sending water to the display quicker than it can drain?

1. It is common to have to throttle a return pump back to a reasonable level, so you don't push to much water. If you are depending on the return for flow, then this is a mistake. Either create a separate closed loop or add powerheads.

2. The hoses you are using have a very small diameter and will only handle a small amount of water. You need a bigger tube, assuming the OFB will handle more water. Most overflow boxes use a standard U-tube which is a 1" tube I believe. See here --

well at this point it won't pump but barely 10 gph. it just won't siphon right with the tubes i'm using...I have to use multiple tubes in order for my overflow to flow atleast 20gph...I just don't understand why it takes so long...my return pump has a valve in the pipe I can set and it's damn near off but still drains my sump quicker than the overflow fills it.

Most overflow boxes are designed to handle X amount (300, 400, 500, 600, 700, etc.) of flow as a maximum. The OFB may be able to handle more but you need a bigger diameter tube. Remember this is a gravity drain, so you are only going to get a moderate amount of drainage in GPH. In general, a 1" PVC drain is only going to handle 5-700 GPH as a best case scenario. If your return pump can push 900 GPH, then it will out pace your OFB unless you throttle it back.