Closed Loop for UV - without dedicated CL holes drilled - Help

[Rollins]

Goal - To Run a Closed Loop in Display Tank - without dedicated CL holes drilled- Checking in with all of you expert plumbers - All ideas welcome TIA!
IDEAS:
1) Running a intake & return line over the back of my tank to feed the UV, running the pump externally. Not ideal, but I am in a pickle at this point in the game. Thinking it would have to be 1" pipe to reach my GPH 1050 goal with head loss
2) Combining my 2 return pumps to return at the same 3/4" return display bulkhead. This would achieve opening up a 3/4" Bulkhead for partial possible closed loop UV application. Thinking this would be possible given that my sump runs around 300gph, and a single 3/4" bulkhead could handle that. I understand that running 2 pumps into the same bulkhead return would require some extra plumbing check valves etc.
3) This is getting kinda crazy, but thinking of using the Emergency external overflow bulkhead as an intake for the UV closed loop. My external overflow has 3 11/2" drains. All go to the sump, all are open 11/2 PVC. First main overflow drain goes to my filter roller thru a valve. The second overflow hole is open 11/2 at top, and only get overflow water if first drain/valve out of adjsutment. The third hole has a taller 11/2" pipe that has never seen water in 2 years, I cant see how it would be possible to actually need this emergency overflow. --- Now needing 1000gph to feed UV, PLUS, 300gph for sump turnover, that means my 2 tank drilled 11/2" holes feeding the external overflow will be sucking in 1300 gph, yet only 300gph would be actually making it down to my sump.

Current Setup - 150 gallon display - 2 Years running
Goal GPH for my 40watt UV is 1050gph
Qty 2 - 3/4" standard tank drilled holes for return
Qty 2 - 11/2" tank drilled holes for EXTERNAL overflow
External Overflow has Qty 3 - 11/2" holes drains to sump - Max Spec Flow rate is 1600gph
Qty 2 - Return pumps from sump for redundancy, both dedicated return on one side
Both returns on flow sensors - Totaling about 350GPH turnover - my filter roller only handles max 500 gph, so tank sump turnover of arond 300gph is its happy zone. I am happy with this turnover rate as well, my sump is very efficient and I already strugggle maining enough nutruents for my corals.
I have 3 pumps to make this somehow work, all can be run internal or external, 2 for return, 1 for UV - all lines will have flow sensors
Sicce DC Adjustable 1000-2500 gph
Sicce DC Adjustable 400-1600 gph
Sicce Non-Adjustable 1900 gph

 

[Formulator]

My returns are not drilled and go up the back and over. They just barely come over the edge so you can’t see them at all looking at the DT. My suggestion would be to switch your return to run over the edge and use the 2 return holes for your closed loop. Seems like the simplest approach to me at least.

 

[Rollins]

I like the idea thank you. Seems the most simple, disaster proof design.

I tend to overthink things, making sure I don’t regret the decision

 

[WhatCouldGoWrong71]

Goal - To Run a Closed Loop in Display Tank - without dedicated CL holes drilled- Checking in with all of you expert plumbers - All ideas welcome TIA!
IDEAS:
1) Running a intake & return line over the back of my tank to feed the UV, running the pump externally. Not ideal, but I am in a pickle at this point in the game. Thinking it would have to be 1" pipe to reach my GPH 1050 goal with head loss
2) Combining my 2 return pumps to return at the same 3/4" return display bulkhead. This would achieve opening up a 3/4" Bulkhead for partial possible closed loop UV application. Thinking this would be possible given that my sump runs around 300gph, and a single 3/4" bulkhead could handle that. I understand that running 2 pumps into the same bulkhead return would require some extra plumbing check valves etc.
3) This is getting kinda crazy, but thinking of using the Emergency external overflow bulkhead as an intake for the UV closed loop. My external overflow has 3 11/2" drains. All go to the sump, all are open 11/2 PVC. First main overflow drain goes to my filter roller thru a valve. The second overflow hole is open 11/2 at top, and only get overflow water if first drain/valve out of adjsutment. The third hole has a taller 11/2" pipe that has never seen water in 2 years, I cant see how it would be possible to actually need this emergency overflow. --- Now needing 1000gph to feed UV, PLUS, 300gph for sump turnover, that means my 2 tank drilled 11/2" holes feeding the external overflow will be sucking in 1300 gph, yet only 300gph would be actually making it down to my sump.

Current Setup - 150 gallon display - 2 Years running
Goal GPH for my 40watt UV is 1050gph
Qty 2 - 3/4" standard tank drilled holes for return
Qty 2 - 11/2" tank drilled holes for EXTERNAL overflow
External Overflow has Qty 3 - 11/2" holes drains to sump - Max Spec Flow rate is 1600gph
Qty 2 - Return pumps from sump for redundancy, both dedicated return on one side
Both returns on flow sensors - Totaling about 350GPH turnover - my filter roller only handles max 500 gph, so tank sump turnover of arond 300gph is its happy zone. I am happy with this turnover rate as well, my sump is very efficient and I already strugggle maining enough nutruents for my corals.
I have 3 pumps to make this somehow work, all can be run internal or external, 2 for return, 1 for UV - all lines will have flow sensors
Sicce DC Adjustable 1000-2500 gph
Sicce DC Adjustable 400-1600 gph
Sicce Non-Adjustable 1900 gph

I’m hard plumbing UV into my tank as well. I’m in the process of final prep, tank shows up in 1-2 weeks. The system is 550g with the display about 400g. It will have 3 CLs. 2 of which will feed the 4 corners of the display, these will be fed by L2s and exiting through sea swirls and RFGs. Each CL that has a UV will use 1-40w and 1-25 W Pentair(for now, it’s what I have on hand). In response to your flow sensors, I have about 10 in use now. Out of the 10, all 10 always stop working after about 10 days. All 10 show inconsistent readings after a few days. Just be careful, they aren’t reliable. I plan to do extensive flow testing on day 1. This way I can document the flow depending on what variable is at play. I plan to also have a gate valve on each of the L2 CLs. I don’t think they can really slow down to a snails pace in a meaningful way. The other I would note is, I’ve never had a pump, short of my Abyzz, that did the numbers the manufacturer said. Calculating head, coupled with the evilness of the flow goes can play havoc on the best laid plans. Happy reefing!

 

[Rollins]

Ok Crew so just got finished. Yes pump head loss / ratings are real. My 1900gph pump landed at 400gph at the flow sensor 8” from the top. Double checked two different flow sensors.

I need 1050gph for parasites and algae per spec sheet. Gonna switch out my return pumps that runs 2500gph and see where I’m at.

Not gonna lie, plumbing and mounting this Uv in my display tank only took way more time than expected. These things are huge like 4 foot and bulky. Hard to integrate to a clean wall only tank setup, especially one that is already plumbed. Just fyi. Hopefully results are a positive.

 

[Rollins]

Some rough pics of install for the next guy. UV itself mounted directly to the wall. I made a heavy metal 2” tall base for the pump. Put a ball valve between the pump and UV. The metal base with mounted pump fits behind my tank stand on the floor.