Simple Physics Question.

[chesterthehero]

This is my second project, the first was the diy overflow from the stickies, between the two I have logged many of hours and pvc cement, also the other half gets pissy if you spill a whole can of purple primer on the flow and leave a permanent tint on the floor.

use silicone till you get everything 100%.. let it run for a week or 3 to be SURE you are happy with it... then use the purple stuff...

 

[nfored]

use silicone till you get everything 100%.. let it run for a week or 3 to be SURE you are happy with it... then use the purple stuff...

silcone is an evil word for me, I used it on my first overflow, was working all was happy, all was good. Then one day the evil dust monster came and I shew him away witm dust rage, and bumped the pipe to hard. Then 600GPH came crashing on the floor like fire from a dragons mouth, within the amount of time it took me to say oh *beep* and pick the pipe up off the floor and put it back in I had noahs ark going on. lost no fish but killed the carpet, as As king Ditech had just requested I hand over all my gold to him; for the furtherment of his kingdom. So I could get new fans or carpet cleaning tools. Leason learned no leak is a good leak and if its not glued your scr**ed.

 

[chesterthehero]

see thats what you get for picking on the dust bunnys


good point though... im constantly giving the pump line a nudge when im moving stuff down below...


*adds it to the list of things that will bite me in the ass*

 

[johnptc]

RIO 3500 900GPH. I am not sure about the pvc being to small, I run a dual 1inch pvc overflow in my 55 Gallon, with a little gaint pew-800-pw 1000 gph. Note that is the GPH at 0ft head, I have not calculated the actull GPH for the head I am running on either pump.

I can't see what the pump has to do with the poor flow of the drian?

well for discussion if the cap is off and you run a 10hp 600 gpm pump it will surely suck mostly air and not much water as the pipe size would be too small for that size pump.........

 

[L.BelcherII]

drill a 1/4" hole in the cap. It'll keep you from syphoning, but won't allow too much air into the line.

 

[nfored]

drill a 1/4" hole in the cap. It'll keep you from syphoning, but won't allow too much air into the line.

There is already a 1/4 hole in the cap and a airline going from that hole to 1 inch bellow the water line. This way its sealed air tight when the waters high, which makes it flow fast, and then when the waters low its unsealed and allows air in.

 

[nfored]

well for discussion if the cap is off and you run a 10hp 600 gpm pump it will surely suck mostly air and not much water as the pipe size would be too small for that size pump.........

I must be missing something the pump which is on the return line, has no problem flows 100% all the time. The problem is the drain/siphon line which is not connected to the pump.

 

[Knowdafish]

The way your overflow is setup capped is a glorified syphon. Capped with a hole in it is the same as if you drilled a hole in the top of a syphon. The ingestion of air interupts the syphon action and slows it down. An overflow from the SIDE of the tank would work better with the way you have it plumbed right now.

For all those that missed it......

 

[johnptc]

I must be missing something the pump which is on the return line, has no problem flows 100% all the time. The problem is the drain/siphon line which is not connected to the pump.

sorry my error........without the cap what is the problem ??

if it is not enough flow.......maybe a larger pipe is the answer

 

[Spankbelly]

With open cap it is only a gravity fed drain. Powered by water pressure from the drain, which has to force it's way back up to the T. This equalizes pressure and slows or stops flow.
With cap closed it is a gravity fed drain and a gravity siphon that empties the T, to be refiled by the drain. The siphon also adds suction to the whole system. Making more flow.
I think.
Your idea to use the air tube to set flow/height is sound. This keeps the pipe and T sealed and under negative pressure. Maintaining the suction siphon.
Mount the air tube flush in a corner to hide it as much as possible. Add a filter of some sort, maybe an air stone?, to keep it from being blocked. Or a more elaborate screen hidden in decor. With a big screen you can check and clear it of debris before it becomes totally blocked.

Edit: I don't think you need much flow through the tube anyway. Just enough to allow passage of some air once the water level drops to the tube opening. This will fill the pipe to the T and stop the siphon.