GULP(!) Am I in over my head?

[jgvergo]

Help

After months of building (see my build thread), I finally got my first reef tank wet last night. I conducted a circulation test and ran into a (potentially big) problem. I was not able to get my Bean Animal full siphon line to fully siphon.

The details:

• My return pump is a Sicce Syncra HF 12.0 Pump (3200 GPH).
• I have ~ 10ft. of head
• I am using 1" PVC pipes
• I have 2 90 degree elbows and 2 45 degree elbows in the return line.
• I also split the return with a 3/4 inch "Y" Loc-Line connector into two 3/4 Loc-Lines at the top of the tank
• I have 2 gate valves, one on the return line to reduce the flow to the DT, and one on the full siphon

I am not getting any water entering my open channel line, so my diagnosis is that the pump is not supplying water at a sufficient rate to make the full siphon line "go full siphon".

In researching the system, I read that a 1 inch full siphon will move about 1000 gph. The pump should be moving ~2400 gph at 10 feet of head. Here is the Syncra 12.0 flow rate diagram.

Is it possible the elbows and Loc Line fittings are slowing the flow to the point I can't achieve a full siphon? Might it be something else?

 

[TheEngineer]

A few thoughts:

1. My guess (using some tools to do the calcs), based on the info you provided is that you are getting somewhere around 20 feet of head pressure. This assumes that gate valve on the return is open all the way. That puts you over the top end of that pump. Since you are getting some flow, I'll assume your numbers are bit off.

2. A 1" line running full siphon down 10 feet will flow over 3000gph. I'm assuming that's how far down the line goes. I also assumed the return was submerged.

3.

Is it possible the elbows and Loc Line fittings are slowing the flow to the point I can't achieve a full siphon?

Yes. Your siphon can pull 3200 gallons an hour going full tilt and your pump can do that with 0 head pressure. You need to close the valve down on the siphon line.

 

[Lenny_S]

A 1" line will move 1000 GPH with just gravity if it's far enough below the water, a siphon will move a lot more than that. I think all you need to do is close the gate valve on the full siphon until the water just starts running into the open channel line. Would not surprise me if that ends up half closed or more.
I don't think it's an issue with the pump output, although you are probably having even more head loss than 10' depending on pipe diameter and number/type of fittings. I'm sure it's still significant flow with that pump though.

 

[Rybren]

Here are a couple of things to check with your system:

a. Are the siphon and OC lines terminating less than 1" below the normal running water level in your sump? If they terminate any deeper, then the siphon line may not be able to purge the air in it.

b. On start up, does the emergency line take any water? If not, it should be taking a bit.
b1. Flow sequence should be Siphon>Emergency>OC

One tip that helped me get mine dialed in was to do the following.

Turn the return off and let everything drain.
Fully open the valve on the siphon (and any other drain valves if you have them)
Start the return pump and let the overflow box start filling with water
Slowly start closing the valve on the siphon until water starts to barely flow through the OC (on mine, the valve is more than 3/4 closed)
Let the system stabilize and watch the lines in the sump for air bubbles. The OC should stop producing bubbles first and then the Siphon should stop.
If you continue to get a lot of bubbles in the OC, then slightly open the valve on the siphon
If you can't purge the air in the siphon, then slightly close the valve

It takes a lot of tweaking and minor adjustments to get it set initially, but once it is set, you shouldn't have to play with it again. It can be a very frustrating process.

FWIW, the normal water level in my overflow box is at the mid-point of the siphon elbow.

 

[ReeferBob]

You could bump your return like to 1.5" you'd probably flow more. But yes I agree with the others, a lot of head and a lot of flow. Crank the valve on the drain until the siphon maintains and you are trickling into your open channel. Also you might need to add more volume that amount of piping can hold quite a bit of water. Make sure to test all flood scenarios.

 

[jgvergo]

icecool2/LennyS/Rybren/ReeferBob, you are the best! I pretty much knew what I had to do but I was a little nervous. This was the first time I've done a plumbing job of this magnitude and having a couple of thousand gph running through my family room had me on edge. Your instructions gave me the confidence to tackle it slowly and methodically, and VIOLA, the whole system is up and running beautifully. It is dead silent at the display tank too. THANKS. On to aquascaping!

 

[Lenny_S]

icecool2/LennyS/Rybren/ReeferBob, you are the best! I pretty much knew what I had to do but I was a little nervous. This was the first time I've done a plumbing job of this magnitude and having a couple of thousand gph running through my family room had me on edge. Your instructions gave me the confidence to tackle it slowly and methodically, and VIOLA, the whole system is up and running beautifully. It is dead silent at the display tank too. THANKS. On to aquascaping!

Excellent!!! Very happy we helped.

 

[Rybren]

Good to hear. What did you end up doing to get it to work?

 

[Mike in CT]

It's incredible how much water will flow in a full siphon. I barely have my siphon valve open and keeps up with my mag 9.

 

[don_chuwish]

Reading Rybren's advice it was like he watched what I was doing yesterday and took notes! My first time too, but finally got it to stop 'flushing' down the siphon or constantly over use the OC (very bubbly!).

 

[aquablizz]

what is the "OC" ???

 

[jgvergo]

OC is Open Channel.

 

[jgvergo]

More complete answer...For a Bean Animal system, one pipe runs "full siphon", one is an emergency overflow and one is "open channel". The flow into the sump is *slightly* above what the full siphon can handle. The extra water (silently) trickles down the open channel.