Flooding tank drains

[Contains Moose]

It wouldn't surprise me that you can siphon way more than your pumps capacity with a 3/4 siphon, at 4 feet up the water would flow like crazy, if weight is an issue then support the pipe before it goes through the floor, you could use flex all the way to the sump,

[Severum]

If I could run 1" or 3/4" from the main drain all the way to the sump I should be able to create a siphon given the gph of the return pump.

I don't have 40' of flex but the pipe would be sitting beams while horizontal and I could rig something to support the vertical part.

Would electical PVC conduit be good enough for this application? Its not like there would be massive pressure going through the pipe since its a drain.

But yes I do see how this is designed for an overflow box. My way of doing it might not work.

[Contains Moose]

Here is a really simple test for you, actual results to the basement will be higher still, take a length of flexible pipe of known diameter, fill it with water then shove one end into the tank and the other end into a 5 gallon pail and see if you can see the surface of the tank fall with the pump running, do this after the pump has been off for a while so you will be able to see it functioning on it's own rather than some going over the weir. try both 1" and 3/4 you will see how it will perform before you go through all these major changes

[Severum]

Thanks for the explanation Pat!

The holes in the tank are at slightly different levels because I was a rookie at drilling tanks... I should have borrowed the drill press from work.

Great suggestion Moose! I tried 1", 3/4" and 1/2".

The 1" tube's siphon has way more flow than my return pump. The 3/4" tube's siphon matched my return pump pretty good. I let it siphon for several minutes with no change in water level. The 1/2" tube reduced my overflow to small trickles

Assuming more flow once connected to the system I'm either looking at a 3/4" main drain with the drain line valved back or a 1/2" main drain with the return pump throttled back.

I still have to somehow get a 90 elbow going up from the emergency drain with the little clearance that I have. I don't think even a street 90 will fit unless I cut it back a little.

[Contains Moose]

Thanks for the explanation Pat!


Great suggestion Moose! I tried 1", 3/4" and 1/2".

The 1" tube's siphon has way more flow than my return pump. The 3/4" tube's siphon matched my return pump pretty good. I let it siphon for several minutes with no change in water level. The 1/2" tube reduced my overflow to small trickles

Assuming more flow once connected to the system I'm either looking at a 3/4" main drain with the drain line valved back or a 1/2" main drain with the return pump throttled back.

I still have to somehow get a 90 elbow going up from the emergency drain with the little clearance that I have. I don't think even a street 90 will fit unless I cut it back a little.

got pics... everything is possible.

[Severum]

I'll snap up some pictures tonight.

Pat, how big are your drains? Are they separate? What's your return pump and how much flow are you getting into your tank from it?

[redbelly]

Both of my drains are 1.5" and I run spa flex 2-3 feet below the floor boards. I have zero restriction on either.
Flow rate over my ctc is above 750 gph.

I am not 100% positive on my exact flow rate, its an estimate.
The pump is 1750gph at the head pressure that I have, but I have a ball valve right as you go into the tank restricting the flow so I use this to adjust the water height level in the overflow. Just dont bury your bulkheads with water or they will try to such air and make a terrible noise. At the same time if its too little water it will allow the sound to come up and make a terrible racket anyways.

A durso style in a slanted overflow is still a possible solution if you want to do that. Its just a fun one to make

[Severum]

Thanks Pat. I've reduced the flow to almost nothing and it still makes a terrible noise.

The back of the tank has a 1.5" bulkhead with a 1.5" 90* elbow going down towards the sump. If I'm able to stick a 3/4" elbow pointing down into the overflow and then change the plumbing to 3/4" pipe right after the 1.5" 90* elbow willl the larger elbow being still there cause any issues for the siphon? (did that make sense)

[Severum]

Photos of the overflow...

[RossW]

I don't have much experience with overflows... but your water level seems high in relation to the bulkhead which makes me think you have too much water running down it to be uber quiet.

[Contains Moose]

Thanks Pat. I've reduced the flow to almost nothing and it still makes a terrible noise.

The back of the tank has a 1.5" bulkhead with a 1.5" 90* elbow going down towards the sump. If I'm able to stick a 3/4" elbow pointing down into the overflow and then change the plumbing to 3/4" pipe right after the 1.5" 90* elbow willl the larger elbow being still there cause any issues for the siphon? (did that make sense)

It shouldn't , how much higher is the next outlet?

[Severum]

The next outlet is about a centimeter higher.

[redbelly]

I don't have much experience with overflows... but your water level seems high in relation to the bulkhead which makes me think you have too much water running down it to be uber quiet.

Agreed, the water level is too high on this bulkhead.
Reduce your flow rate and it will be quieter.

For Shauns coast to coast on his 220g he built a square coast to coast overflow box so that he could have durso standpipe in the overflow box and when it was nex it made a HUGE diff on noise.
He has now removed the durso pipe and will be adding a couple of strainers instread.
Now that there is a bio film in the pipes they are very quiet. Every now and then when the hood doors are open you hear a faint sound of water moving, with the doors closed though you really cant hear anything. And thats a 6' coast to coast overflow feeding into 2 x 1.5" lines.

[Contains Moose]

The next outlet is about a centimeter higher.

So if you installed a 3/4 elbow pointing down on one of them and installed elbow pointing up on the other one what distance can you achieve between the ends of the two elbows?

[Severum]

I'll try that this weekend. I should be able to get a few inches separation.