UV install plumbing question

[shadyraro]

I’m looking to install an aqua twist 25w UV into my setup, but I have a question re plumbing.
I plan on tapping into a return manifold to use as the UV input as my sump is too small to run its own pump (Cade 900).
I was then wondering if I could tap into another return manifold further down the line to run the UV output water into as I don’t want to return UV water to the sump and just recycle the same stuff over but prefer it to go into the display.
Would this work?

The left circle would be the UV input line and right circle the output.


My other option is running a pvc return from the UV back into the display.

 

[UncommonSense]

This can work, but it requires a third valve on the return line, between the UV inlet, and UV outlet ports of the manifold! (Possibly a gate valve for more precise control)

Otherwise, you’ll have an undetermined volume of water passing through the UV, likely little to none as the water prefers to take the straightest path through the plumbing…

 

[shadyraro]

This can work, but it requires a third valve on the return line, between the UV inlet, and UV outlet ports of the manifold! (Possibly a gate valve for more precise control)

Otherwise, you’ll have an undetermined volume of water passing through the UV, likely little to none as the water prefers to take the straightest path through the plumbing…

So although I could adjust the UV’s input flow via the ball valve, and the ball valve on the output manifold would always remain open, I’d still need a third valve?

 

[UncommonSense]

So although I could adjust the UV’s input flow via the ball valve, and the ball valve on the output manifold would always remain open, I’d still need a third valve?

Yes, water’s lazy, and will always take the path of least resistance!

This said, you’ll end up with little to no water preferring to take that 90 degree turn into the UV, vs. just passing straight by it through the fully unrestricted return plumbing!

 

[shadyraro]

I get what you’re saying but I have run reactors off those manifolds in the past and never had an issue with lack of water flow.

 

[UncommonSense]

I get what you’re saying but I have run reactors off those manifolds in the past and never had an issue with lack of water flow.

As in, you’ve had reactors plumbed from one return manifold port to another and had water flowing through with no other changes?

Or were these reactors being fed by manifold ports, and discharging back into the sump?

 

[shadyraro]

As in, you’ve had reactors plumbed from one return manifold port to another and had water flowing through with no other changes?

Or were these reactors being fed by manifold ports, and discharging back into the sump?

Fed by manifolds and back into the sump.
I guess I could just plumb it to try it out, if it doesn’t work I’ll just go a different route.

 

[UncommonSense]

Fed by manifolds and back into the sump.
I guess I could just plumb it to try it out, if it doesn’t work I’ll just go a different route.

Ah, this worked because flowing back to the sump is the path of least resistance from the return line, vs. fighting gravity to get to the display!

What you’re proposing doing with your UV is pressurizing both inlet and outlet from the same return line, to essentially the same pressure… this will net close to zero water movement, which in-itself can cause the UV to overheat!

 

[RobertK]

Are you sure you can't find room in your sump for a small pump? I'm running my UV with a Sicce Syncra SDC 3.0 DC pump, its pretty small and allows you to control the flow rate through the UV, and output to a downstream sump compartment.

 

[shadyraro]

Are you sure you can't find room in your sump for a small pump? I'm running my UV with a Sicce Syncra SDC 3.0 DC pump, its pretty small and allows you to control the flow rate through the UV, and output to a downstream sump compartment.

It’s a small sump and she’s pretty crammed in there, but an output back into the sump might be the easiest option.

 

[shadyraro]

@UncommonSense Can I have the UV input hose facing down and output facing up? It would just make it easier to plumb it doing it this way.

 

[mcarroll]

If you're just trying to have "clear water" then installation can be however you want....but if you're hoping at all to target parasites with it, you'll want a more robust installation where water is drawn from the display and returned to the display. (Either is fine depending on your intentions.)

2¢

 

[UncommonSense]

@UncommonSense Can I have the UV input hose facing down and output facing up? It would just make it easier to plumb it doing it this way.

This works! The goal here is ensuring that air bubbles are exhausted from the UV chamber during normal operation, vs. accumulating and causing issues ranging from poor performance to full-blown overheating! (Hence orienting the UV’s outlet vertically)

It’s worth noting that the UV can run dry and overheat in this configuration, in the event of a pump failure… this is more of an issue if the pump running it is questionable, as most feed pump shutdowns are power outage related! (Meaning the UV sterilizer typically turns off when the UV feed pump turns off… just keep it in mind!)

 

[shadyraro]

Thanks guys

 

[Freenow54]

This works! The goal here is ensuring that air bubbles are exhausted from the UV chamber during normal operation, vs. accumulating and causing issues ranging from poor performance to full-blown overheating! (Hence orienting the UV’s outlet vertically)

It’s worth noting that the UV can run dry and overheat in this configuration, in the event of a pump failure… this is more of an issue if the pump running it is questionable, as most feed pump shutdowns are power outage related! (Meaning the UV sterilizer typically turns off when the UV feed pump turns off… just keep it in mind!)

Would a check valve upstream prevent that ?

 

[UncommonSense]

Would a check valve upstream prevent that ?

it would, assuming the check valve is regularly maintained and doesn’t have enough organisms or biofilm on its sealing surface to leak!

You can also have both inlet and outlet facing up, if a UV allows, to ensure that the UV housing remains full of water in the event of a pump failure!

 

[Freenow54]

it would, assuming the check valve is regularly maintained and doesn’t have enough organisms or biofilm on its sealing surface to leak!

You can also have both inlet and outlet facing up, if a UV allows, to ensure that the UV housing remains full of water in the event of a pump failure!

yes that is how mine is on my DI system , and was recommended. I was just throwing things out for the person who wanted to plumb it differently

 

[shadyraro]

Are there any cons with plumbing the return directly into the uv and using it inline as the main return?

I can’t get decent flow for the uv via a manifold, mainly because I’ve plumbed the uv outlet to go directly back into the display.
I have a cor-15 return and I added a vectra s2 to now feed the uv, these 2 pumps are both in the return section but they’ve increased the overall return flow a lot.
Tank is 350 litres and I was running roughly 3x flow before the uv, it’s an LPS and softie setup so not much flow is needed.
With the uv installed I’ve basically doubled the flow and some, so it got me thinking why not just use the cor to run inline as the recommended uv flow for algae /water clarity is 110 lph per watt.
This is close to what the current combined return flow is now, so in my head it makes sense to delete the Vectra and tap the uv outlet into the main return line.

FWIW the sump is too small to put the Vectra anywhere upstream, I have a ReefMat, skimmer and Nyos reactor crammed into it already.

 

[UncommonSense]

As long as your UV’s target flow rate line up with tank size and return pump capabilities, nothing stops you from plumbing your UV directly on your return!

It can be worth having a UV bypass plumbed into the return as well, given that UV sterilizer housings typically need replacement every 3-5 years, meaning you might need to run the return pump with the UV disconnected at some point!

 

[mcarroll]

Are there any cons with plumbing the return directly into the uv and using it inline as the main return?

I can’t get decent flow for the uv via a manifold, mainly because I’ve plumbed the uv outlet to go directly back into the display.
I have a cor-15 return and I added a vectra s2 to now feed the uv, these 2 pumps are both in the return section but they’ve increased the overall return flow a lot.
Tank is 350 litres and I was running roughly 3x flow before the uv, it’s an LPS and softie setup so not much flow is needed.
With the uv installed I’ve basically doubled the flow and some, so it got me thinking why not just use the cor to run inline as the recommended uv flow for algae /water clarity is 110 lph per watt.
This is close to what the current combined return flow is now, so in my head it makes sense to delete the Vectra and tap the uv outlet into the main return line.

FWIW the sump is too small to put the Vectra anywhere upstream, I have a ReefMat, skimmer and Nyos reactor crammed into it already.

Not making a recommendation, just giving some ideas as requested:

You lose the ability to shut it down for maintenance without shutting down the system. (A UV outage can mean a return pump outage.)

You lose the ability to control flow to the UV independently of the system flow. Mostly lost is the ability to lower the flow rate to target larger cells like parasites. However if that (low) flow rate happens to be compatible with your sump's flow rate, then go for it.

Maybe the ReefMat and reactor can be demoted and removed so you have room for other priorities? On a reef tank, sometimes these are unnecessary extras anyway.