How to plumb a dual overflow

[CStrickland]

I'm doing separate gate valves. Supposed to be much easier to tune the siphons.

 

[kmbyrnes]

I'm doing separate gate valves. Supposed to be much easier to tune the siphons.

2 gate valves.
Each siphon will move at slightly different rates due to differences in the length and layout of the plumbing causing flow restrictions.
It will also prevent a single clog from causing a flood. The gate valve presents the best opportunity for a snail to back things up

 

[IdahoCindy]

2 gates. Each side has a different flow rate.

 

[Wazzel]

If it were me I would do dual herbies and go over the top with the returns. If you have a hood no one is going to see them. I would also do dual returns each on its own pump. I am going dual pumps on my 120, kind of a working back up. If I loose one pump I still got one working.

 

[chimmike]

Thanks for a the info guys. I plan on doing the 2 full siphon drains with one emergency and one return.

you don't need 2 full siphon. you could run a "spread out" style beananimal with one emergency and the one return.

If flow out of the single return is a concern, split to 2 returns then use loc-line and penductors.

I'd not run simple durso. Just not enough flow, and they're noisy, and leave no room for emergencies.

 

[jacksonpt]

It make me a little nervous only having only return but i guess with two full siphon drains I should be able to put quite a large return pump on the tank.

Are you going to have so much flow that you need 2 full siphons?

I'm speaking from theory, not from experience here, so take this for what it's worth... but why wouldn't you run 1 full siphon, 1 trickle, 1 emergency and 1 return?

 

[kmbyrnes]

Why would you need two returns? As long as the water gets back to your tank, all is well. They will not be providing significant flow in the DT.
My reason for 2 full siphons on the 350 was silence. The tank is a room divider and is directly behind my easy chair. IMO it's also better to have higher flow for better surface skimming and to help prevent stagnation in the overflow box.

 

[ajholms0427]

Why would you need two returns? As long as the water gets back to your tank, all is well. They will not be providing significant flow in the DT.
My reason for 2 full siphons on the 350 was silence. The tank is a room divider and is directly behind my easy chair. IMO it's also better to have higher flow for better surface skimming and to help prevent stagnation in the overflow box.

The reasons for the two return is simply a fail safe. If something were to go wrong on one side the other would still be moving some water.

 

[ajholms0427]

Are you going to have so much flow that you need 2 full siphons?

I'm speaking from theory, not from experience here, so take this for what it's worth... but why wouldn't you run 1 full siphon, 1 trickle, 1 emergency and 1 return?

The two siphon drains would be used so that there is not stagnant water sitting in one overflow.

 

[JMorris271]

I use my trickle as and the emergency if needed and it works well. I ran a test to be sure.

 

[dsteinmann]

How Did you end up doing this? I need to plumb my 240L I only have the 4 pipes available all 1 1/2. What should I do