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Modifying overflow setup

787 Views 11 Replies 3 Participants Last post by  BruceF
I have a glass holes 1500 set up on my 125 that has been going for about a year. I was going through so much co2 I cut it out and have lowered lighting a bit. I would have used a hernia overflow if I had done more research but don't feel like breaking down everything and drilling more.

I had an idea of running an additional drain over the rim with 1 1/2 inch PVC that would be controlled with a ball valve and run into the sump directly. In running this additional drain it would be very much like a herbie style overflow and as long as the inlet is high enough in case of return pump failure, it should work correct?

If the drain loses the syphon, everything works through the glad holes box...

What am I not thinking about?

My end goal is to use co2 much more efficiently, all the while not having to break things down and start over...

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Most of the time people fault the sump itself for the co2 loss. Why do you think it is the overflow that is the problem?
The steadier the flow the less air will be drawn in. If you hear a lot of continuous gurgling you may want to adjust the drain hose so as to break any internal siphons that form - on my tank that used to create a 5-8 sec repeating gurgle.

Can you shut off the sump return pump and check your Co2 levels? it would be good to be sure if the sump and drain is the problem- could also be the Co2 diffuser system.
I was using a needle wheel and running it through a reactor, and then through the return pump and wasn't able to ever get the co2 high enough.

My main goal is to get a full siphon through a third drain that will go over the top if the rim and controlled by a gate valve. If I lose the siphon it moves al the water through the twin 2" inch drains (which is what I am doing now) and if the pump fails or a power outage, the drain will be placed hug enough against the water line the break the siphon once enough water line drops.

My current set up isn't that loud really. The glass-holes design is pretty sound proof once you get some grime built up, but there is tons of air that is being sucked down the tube.

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I don't see why you can't do that. Just make sure the siphon is high enough in the tank so it will stop draining before it overflows the sump. I use a bunch of siphons and the hardest part is designing them so they are easy to start.

I still would think the bulk of the co2 is driven off in the sump and the surface of the tank. Is it covered?
The sump has almost 0 surface movement. The only movement comes from the air being sucked down into the sump from the overflow.

I am not currently injecting any co2 because I was going through it so fast and I didn't want to refill every month.

My main concern is to prevent a flood and excess amounts of tank watching.

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I should add the sump is a 29 gallon tank that is separated into 3 sections by 2 mattenfilters. So there are no socks or baffles that cause any additional turbulence.

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It will be difficult to control water flow in the siphon over the rim as you describe because for it to have a meaning full effect it should carry 70% of the total return volume. That requires more precise control than a manual valve. If you want to spend the $ its possible to control the siphon with a electric valve ($30) and float switch on the tank ($10). When the level rises the float will energize the valve and let water drain down. If the return flow is slow and the water level drops too far the float will de-energize the valve closed. That setup would self regulate and is relatively trouble free. You would arrange the height of the float switch to maintain the water level just below the overflow (which in this case shall serve as a backup).
The intention for the siphon is to have it carry 95% of the return volume. The other 5% would be incidental and surface skimming via the glass-holes overflow box.

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Just as well since this makes it even more important to tightly regulate the siphon drain.
So I put something together tonight that I think is what I am trying to achieve. However...I think I didn't get a large enough diameter PVC. It works well, but too much water is still being drained through the over flow box than what I had hopes for. If dial back my return pump way back, it gets me closer. I think I was anticipating much more flow from 1" schedule 40. I didn't want to go too large because I wanted better control.

I will be painting the intakes black before I permanently set things up.

Should I do another 1" drain or pull this one and out in 1 1/2"?

And yes I know there is so nasty algae. I am going to rescape the tank here shortly, but wanted to figure out the plumbing first...

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Never mind....I guess I had lost the siphon when I was fine tuning. The 1" will outdo my return pump so I think this will work.

Any suggestions on how I can make a cheap (ok looking) box to hide the PVC and also prevent creatures from getting sent to the sump?

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I use a black intake sponge but it only fits a 3/4 pipe I think. Home depot sells them in the pond gear department. Another thing I did was cap the end of the pipe and cut slits with a band saw.
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