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?