Can I run an external protein skimmer from a manifold?

[PuertoReef]

Hello,
I am designing a manifold that will be fed by a separate pump, closed loop, it will feed from my return pump chamber and it will return to the display tank. On this loop, I intend to have a reactor and maybe UV. This loop goes into a closet that is adjacent to my display tank. I am considering putting my external skimmer in that closet also and I am wondering if I can feed it from the manifold or not. My understanding is that the external skimmer uses a gravity drain. I can certainly locate the external skimmer above the height of the sump and display tank, however, I am concerned that if it is just gravity draining into the return side of a manifold that is also taking the return from reactors and UV, I worry the back-pressure from those other "legs" in the manifold may interfere with the flow rate out of the external protein skimmer. Any thoughts on whether this could work? Please see attached sketch of the proposed setup and please let me know what you think, thank you in advance.

 

[ca1ore]

Hard to answer because it will depend a lot on the design of the skimmer. Is it a recirculator or a pass-through? Is level set by a gate valve or an overflow tube? My external skimmer is a recirculator and uses an overflow tube to set height so it is not particularly sensitive to the gph of the feed pump.

 

[twentyleagues]

I did this years ago and found that the skimmer worked ok this way but it worked much better with its own dedicated pump. Bashsea custom, level conrolled by gate valves.

 

[PM Corals]

Yes, but you would want to have a flow meter to monitor flow

 

[PuertoReef]

Yes, but you would want to have a flow meter to monitor flow

Yes, above my gate valve feeding the skimmer off the manifold (and actually above each gate valve), I have a flow meter, which I left out of my drawing to keep it simpler. Updated sketch attached.

Hard to answer because it will depend a lot on the design of the skimmer. Is it a recirculator or a pass-through? Is level set by a gate valve or an overflow tube? My external skimmer is a recirculator and uses an overflow tube to set height so it is not particularly sensitive to the gph of the feed pump.

This is a Regal 200EXT which is recirculating, it does have its own level-setting gate valve, and it does have an overflow tube.

The issue I am concerned about is that water would go "up" from the return manifold into the "outlet" from the skimmer, or cause its flow to slow down.

I have thought of putting it on its own loop, the issue is, my hole in the wall through which I am running the pipes is presently only large enough for one circuit. So if I don't run it off the manifold, I would run an internal skimmer in my sump. The advantage of doing it off my manifold though is that in the adjoining room where I have this manifold, I can easily drain the skimmer collection cup to sewer line, which is a nice feature compared with having to empty it regularly in the sump.

 

[MyFirstCar]

I'd be concerned about the return pump putting back pressure on the manifold outflow line

 

[BeanAnimal]

This is not going to work well and is a nightmare of valves and dynamic pressures that will never stay in balance.

Ignoring that the skimmer will never be stable, for this to have any chance of working it would need more check valves to control direction (adding further complication and cost) but If properly designed would not have ANY check valves.

Do yourself a favor and put the skimmer on its own pump and let it gravity return to the sump.

Likewise, skip the idea of trying to split flow through reactors and then trying to merge them back with the return pump flow. You are asking for more balancing headaches with the overflow and reactors making things unstable. Return this to the sump as well.

 

[PuertoReef]

Likewise, skip the idea of trying to split flow through reactors and then trying to merge them back with the return pump flow. You are asking for more balancing headaches with the overflow and reactors making things unstable. Return this to the dump as well.

Thanks for the advice, I think by trying to return direct to the tank I was trying to follow the best practice for UV, where folks claim the best way to do UV is as a true closed loop back to the DT. But I agree the balancing headaches would add up quickly.

I will return the manifold back to the sump, and I will figure a way to keep the skimmer on its own pump, gravity draining back to the sump.

 

[BeanAnimal]

You can put the UV in-line if you want and/or create a bypass for it for maintenance, but it really does not matter where it returns to. There is more unfounded or silly advice in this hobby than there is fact based advise.

What you want to avoid is devices inline with the returns that change flow over time, or splitting the return pump flow and sending part of it to devices like that. What happens is that your overflow never stays in balance as the in-line filters (reactors, whatever) change back pressure/flow as they do their jobs. Skimmers in the same loop with devices like this never stay adjusted either.

 

[PuertoReef]

Here is my simpler design. A pump for the skimmer loop would feed from the skimmer section of the sump and return to that same section. I feed two devices on the skimmer loop: the external recirc skimmer, and the UV sterilizer. Ordinarily I would run the entire thing at 900 GPH through both the skimmer and the UV. If we needed to adjust to run the UV flow slower for protozoa, I could re-adjust the system to send ~160 GPH into the UV with most of the flow bypassing the UV into the skimmer feed using the gate valves shown. I would not expect to make that change often, but in theory the system would allow running the UV slower than the skimmer if desired. Any other reactors such as ozone or carbon would be fed by dedicated pumps inside the sump cabinet. Feedback on this plan is welcomed, thanks again for the advice.