Dual Herbie - can't purge all air

[Sethjamto]

Just finished setting up a dual herbie on my 8ft 300g. The tank is in the garage going through a leak test of the plumbing right now. On the herbies, I have a 1.5" main siphon in each corner overflow and a 1" emergency in each corner overflow.

The main siphons are about 8" below the waterline in the overflow and the emergencies are about 1" below the weirs.

The main siphons T together at the sump into a 2" line with a 2" Spears gate valve. The siphon kicks right in when I turn the return pump on and can adjust it perfectly with the gate valve, but the line is still pumping bubbles into the sump! I have the drain line submerged about 1.5" below the water line.

I have let it run for a few hours now hoping the bubbles would purge out, but they haven't yet. Each main siphon line comes out of the corner overflow and both travel and equal distance (4ft) horizontally to Tee together into the sump.

Ideas? Will the air purge over time?

[Sethjamto]

I know the horizontal run is not preferred, but that's my only option. I "could" have the left one drop straight down into the sump, but the right one HAS to travel a 4ft horizontal run to reach the sump. I just wanted them tied together so I can balance both overflows together off the one gate valve.

[v10king]

In my experience, it takes some time form the air to completely purge. I never had an issue before with bubbles though.

[ca1ore]

You sure the siphon is not sucking down bubbles generated by the tank overflow? Another possibility is a break in the plumbing somewhere that is acting like a venturi.

[rioshilo]

Originally Posted by Sethjamto

Just finished setting up a dual herbie on my 8ft 300g. The tank is in the garage going through a leak test of the plumbing right now. On the herbies, I have a 1.5" main siphon in each corner overflow and a 1" emergency in each corner overflow.



The main siphons are about 8" below the waterline in the overflow and the emergencies are about 1" below the weirs.

The main siphons T together at the sump into a 2" line with a 2" Spears gate valve. The siphon kicks right in when I turn the return pump on and can adjust it perfectly with the gate valve, but the line is still pumping bubbles into the sump! I have the drain line submerged about 1.5" below the water line.

I have let it run for a few hours now hoping the bubbles would purge out, but they haven't yet. Each main siphon line comes out of the corner overflow and both travel and equal distance (4ft) horizontally to Tee together into the sump.

Ideas? Will the air purge over time?

I would be pretty nervous about using the smaller 1" line as my emergency plumbing. How much flow are you planning thru the sump? Can you switch the siphon and emergency plumbing around the other way?

I have not run a merged herbie setup, but I would think that it would be difficult to match the overflow levels due to the differing levels of restriction that the siphon encounters on its way to the tee, even if all the runs seem equal. I would think you would want individual runs and restrictors.

But, like I said, I have no experience in a merged setup. With that said, if there is air bubbles coming out then you might have a loose or leaking connection sucking in air (likely after the gate valve), or, it's sucking air down from the top of the water level in the overflow (which you would see and hear), or, there is still some air in the suction pipe that needs to continue working its way out (probable due to the horizontal runs, and the large pipe size)

[Sethjamto]

I've read good things about teeing them together. Some prefer to and others say not to. It seems like a 50/50 split on opinions on that.

I'm curious of it's sucking air somewhere as I let it run all night in the garage and just checked it. Bubbles are still there.

With the drain being 8"+ below the waterline in the overflow I'm 99% confident it's not getting air in that way, otherwise I'd see the bubbles in the overflow getting sucked into the siphon.

I see your thought on the 1" lines for the emergency, but with two 1" lines (one in each overflow), I'm good to go. I'll have my reef angel shut the return pump down automatically if the return section of the sump gets too low (ie: clogged lines).

I'll do some more playing with it this morning after I finish my coffee....

[Sethjamto]

Okay....I figured it out. Mostly.

I did not glue the last piece of 2" pvc that comes out of the 2" gate valve dropping into the sump. I originally did not glue it so that I could slip it out for whatever reason. I held my hand around it and instantly heard a difference, as a bulk of the noise was right there at the valve. So for a quick test, I wrapped it tightly with electrical tape to reduce the air it was sucking just to test. Now the bubbles are reduced DRASTICALLY and it is nearly dead silent!

I still don't want to glue this one piece, so I'll just pick up one last union to place right there so that I can pull the gate valve out in the future to clean it, and then it'll be good to go!

Thanks guys!!!

[rioshilo]

Right on. Glad you got it figured out