Close Loop

[Saltyanimals]

Not sure if this is called closed loop or what, but I'm struggling with UV plumbing. Trying to avoid pumping sump water through UV and back to the sump, but properly go to DT. Need some feedback on the diagram below.

Basically single pump to display. I have a 3 head manifold that I've plumbed in (M1,M2,M3 each with gate value). Will be hooking UV to M2 and it'll return via the dotted line into a Tee off the main return pump line. Question is to water flow and direction. I'm hoping by restricting the flow to M2 to slower, the pressure will be enough to push water to the return tee and ultimately to DT. Is this effective, or will there be some recirculating loop somewhere and I'll never effectively process all tank water.

I'm going in circles maybe over thinking, but looking for help. Thanks@

 

[Saltyanimals]

Question 2: Since it's tee'ed off in the picture above, will the flow divide at that point and essentially go into the UV the wrong direction? Ideally I presume the return tee should be closer to the DT entry, but my options are limited to anything along the pump vertical pipe unfortunately.

 

[Snoopy 67]

Instead of a TEE I would use a WYE fitting to help flow go in 1 direction.

 

[Saltyanimals]

Instead of a TEE I would use a WYE fitting to help flow go in 1 direction.

Interesting. And that would force the water to go upwards in my diagram and allowing me to reenter anywhere on that vertical pipe coming out of the pump?

 

[reddogf5]

Yes, as drawn the flow will go along the dotted line, through the UV the opposite direction from what you want, and out M1 & M3.
To get flow through the UV and back into the return, it needs to rejoin downstream of the manifold tap.
Also, depending on how restrictive the UV and its plumbing is, you may need a restriction between the manifold tap and UV return to drive any flow through the UV. But I think UV units are almost like a straight pipe, so probably not.

 

[Saltyanimals]

Yes, as drawn the flow will go along the dotted line, through the UV the opposite direction from what you want, and out M1 & M3.
To get flow through the UV and back into the return, it needs to rejoin downstream of the manifold tap.
Also, depending on how restrictive the UV and its plumbing is, you may need a restriction between the manifold tap and UV return to drive any flow through the UV. But I think UV units are almost like a straight pipe, so probably not.

That really helps. So either 1) I rejoin downstream of the manifold tap (not possible for me) .. or 2) do as @Snoopy 67 mentioned and do a wye in place of my current re-entry tee.

Man you guys are awesome. Thank you!

 

[Saltyanimals]

Yes, as drawn the flow will go along the dotted line, through the UV the opposite direction from what you want, and out M1 & M3.
To get flow through the UV and back into the return, it needs to rejoin downstream of the manifold tap.
Also, depending on how restrictive the UV and its plumbing is, you may need a restriction between the manifold tap and UV return to drive any flow through the UV. But I think UV units are almost like a straight pipe, so probably not.

Crap. Didn't work.

What ended up happening was the water would diverge at the wye going in the wrong direction into the UV. However it would go to a certain point and lose the pressure thus not going all the way up through the manifold. I suspect that problem is with the pipe size and pump power @ 2000GPH max. This entire plumbing from my diagram is 3/4.. I'm suspecting that I need to reduce down to 1/2 when existing the UV and into the WYE (dotted lines in diagram)

Do you think this reduction would help or do I have to rejoin downstream of the manifold which would rebuilding the entire manifold which I've already cut, glued, etc. Thanks!

 

[PigDaddyF15E]

Take this for what it's worth. I don't have a tank yet...I'm planning it...but I've been digging into this. I'm sure the people with more experience will chime in.

I think the right answer is to rebuild and have the rejoin downstream of the manifold. Forgot to add gate valves between M1 - M2...and between M2 - M3 so you can cut any one off from the system.

 

[PigDaddyF15E]

Now that I think about it. There was someone else who posted on here about running a second pump and plumbing the UV direct to the DT. So...second pump in your sump....through UV...then directly back to DT. Never connects to the plumbing you already have. You then put a "nozzle" that hangs from the back of the tank so the water out of the UV flows directly into the tank. I'm not keen on the idea as I don't like the additional nozzle inside the tank...I'm more of the opinion the tank is a piece of art and I want the minimum amount of things hanging/dangling/coming out of the tank...that's we use sumps in cabinets. Just my opinion

https://www.bulkreefsupply.com/return-jet.html

 

[Chrysemys]

Two thoughts on this I hope they help. Why not plumb the UV in that horizontal section of your return line? I assume because the UV system isn’t rated for your full flow? Or is it maintenance related?
Seconds I understand you don’t want to plumb it into the sump. I assume this is because you don’t want “clean” water going right back through “dirty” water. So could you plumb it so it returns right near the intake of your return pump.

 

[Saltyanimals]

Two thoughts on this I hope they help. Why not plumb the UV in that horizontal section of your return line? I assume because the UV system isn’t rated for your full flow? Or is it maintenance related?
Seconds I understand you don’t want to plumb it into the sump. I assume this is because you don’t want “clean” water going right back through “dirty” water. So could you plumb it so it returns right near the intake of your return pump.

typically space constrained along with plumbing constrains that I have as well to where I can 'wye' it back to return line after the manifold. And yes you want to plumb as much water through it and directly back to your DT as recommended by the UV makers to ensure you turn over enough water to target bugs or algae depending on your need. Plumbing back to sump just means you'll turn over sump water more often and not enough will get to DT running less efficiently.

And to Pdaddy's diagram. I recommend you do unions everywhere possible so you can remove sections and make your heads expandable. I built mine with 3 as you can see, but I can add more heads as needed. I wouldn't however put a gate valve in your diagram there b/c you'll end up setting flow once for all 3 heads to share.. instead add a gate valve before each head. Going back to my diagram on this post, put it at each "M" which I have.. but didn't label. Now that I'm an expert in this lol .. going back to my original sketch.. I think I have no option but to find a way to wye it after the manifold @reddogf5 recommended.

Here's mine. hard to see in photo, but I don't have enough length on the horizontal return to wye it back in.. hence having to wye it lower as in my diagram. ...proving didn't work for me.

 

[threebuoys]

I think you are making it more complicated than necessary. Just plumb the UV into the return so that 100% of the return flow goes through it before it ever reaches the manifold. Don't feed it off the manifold. I know, some say the flow will be too fast. I disagree.

 

[Saltyanimals]

I think you are making it more complicated than necessary. Just plumb the UV into the return so that 100% of the return flow goes through it before it ever reaches the manifold. Don't feed it off the manifold. I know, some say the flow will be too fast. I disagree.

this is the simplest but it does not agree with the science when you break it down to contact time per UV watt which is driven by a particular flow based on your goal. Your too fast may be fine if you’re looking at algae goals, but not parasites.

BRS made some videos recently that documented this. Doing this would require me to tune down the flow thru UV to lower 200-300 GPH which isn’t enough for a large tank if I had to plumb 100% of the water. .. although 100% water is however ideal. Flow control gate valve is the way to go unless you have a dedicated 2nd pump DC to tune flow rate.

 

[threebuoys]

I've seen those videos and i've read quite a few reviews as I'm sure you have. I don't think the "science" is accurate. I would love to see some documentation that describe exactly how the tests that determined that different flow rates were proven. All I've seen has been based on open systems such as those in municipal or industrial water plants.

Below are comments I've posted elsewhere. I certainly don't have scientific proof for my theory either, but anecdotally, I've been very satisfied with my experience. Sorry to be long winded below, and in any case, UV sterlization is definitely beneficial


"My thoughts FWIW.....keep it simple and cheap, don't over engineer to fix what's probably inconsequential issues.

Plumb it directly in the return line to the tank. No need to buy a second pump or add additional plumbing.

Run UV full time, why wait until a problem occurs?

Run at whatever flow rate you desire for the return to tank, don't worry about altering the speed to accommodate the UV.

I have read the various opinions/recommendations about flow. Some say it depends on what problem you are trying to solve. For example, the reproduction rate of certain bacteria that causes cloudiness in the water column is to double every 20 minutes or less. In that case, the higher flow rate will more than keep up with the bacteria population explosion and aid in water clarity.

Some feel that a slower rate will be more effective in fighting parasites. Likewise, algae in the water column can be tackled by UV, and since it reproduces more slowly, why use a fast flow rate.

In either case, the UV alters the DNA of single cell life to prevent reproduction.

I view it a bit like exposure to the sun's UV rays. If every 5 minutes of sun I get is followed by 5 minutes of shade, I'm still gonna get sunburned if I'm exposed too long. Likewise for the bacteria. If I have a flow rate of say 5 to 10 times tank volume per hour, then the parasites I'm trying to target are still getting exposed to 6 to 12 minutes of UV every hour while the bacteria with the rapid reproduction rate are still getting exposure before they are able to double in population in 20 minutes.

I can turn off the power to the sterilizer if I get concerned that I'm using too much UV (to extend bulb life perhaps), but so far that's not a problem. I can also plug it into a receptacle/switch shared with the return pump to make sure it is turned off anytime no water flow.

A lot of room for different opinions based on individual experience. In any case, I recommend the use of a UV sterilizer and look for the cheapest you can buy. Again, they are really very simple and most of the products on the market, high or low priced, use the same replacement bulbs.

"If you are able to find documented flow rates, as opposed to suggested flow rates by vendors (of which I have seen many), I would also like to see it. All I've been able to find with reasonable documentation are flow rates in municipal water treatment plants. Of course that is a much different environment. Not only is the scale of operation in a much bigger universe, but a major difference is the water treatment plants are not closed systems as our aquariums are. Hence, my recommendation for rapid turnover. Water treatment plants keep each ounce of water in continuous exposure for a longer period of time which destroys all pests before the water is distributed to their customers. We on the other hand return the water into a closed system where it can be immediately reinfected by what is there. Some of the bad bacteria we fight to remove from the water column (often those repsonsible for bacteria blooms) have a documented reproductive doubling rate of less than 20 minutes. So, the best way to fight that is to have a cycle that flows 100 percent of the water in less than 20 minutes. Other pests, larger than 1 cell may require longer exposure which in a closed system is accomplished by repeated passes in the smaller UV devices we have available rather than one that might be multiple meters long. I wish I could offer a scientific study to validate what I'm saying, but I haven't found it yet. My logic may be flawed, but I believe the 5 - 10 water turnovers an hour in a closed system is the best way to match what happens in industrial water plants. And so far, I have been very pleased with my experience which as I've pointed out is anecdotal at best."

 

[threebuoys]

To support my theory another bit of information from

Germicidal UV Dose UV Irradiation Dosage Table

Germicidal UV dose table shows the UV dose needed to inactivate germs

www.americanairandwater.com

quote:

"Please note that many variables (air flow, humidity, distance of microorganism to the UV light, irradiation time) take place in a real world environment that make actual calculating of the UV dosage very difficult. However, it is proven that UV light will kill any DNA-based microorganism given enough UV dosage. UV breaks down DNA on a cumulative basis. Therefore, as air circulates through the ductwork of an HVAC system containing an UV light, the UV light continuously disinfects the air. If a microorganism is not effectively deactivated on the first pass through the ductwork, the UV light will continue to break its DNA down on subsequent passes. Microorganisms do not sit in a static environment in HVAC systems except on coils which can be exposed to UV light also. Microorganisms multiply rapidly if not controlled. The UV light helps to reduce airborne microorganisms from the indoor environment."

 

[Saltyanimals]

Appreciate the opinions. I'm an engineer by profession and not a biologist thus unqualified to comment on the science beyond what we've all read on countless places. Those folks that are more knowledgeable down to UV at the molecular level. I'll leave it there for the smarter biology types to debate.

Back to this thread on plumbing and flow rate. =)

I believe @reddogf5 was correct in plumbing the wye upstream. I ended up redoing the point where the plumbing tees into the manifold. Essentially moving it further down the vertical pipe from pump and putting the wye in place where it splits in the photo above. I was able to salvage much of the plumbing due to the use of the unions in my original design. This reiterates the tip on using unions where possible.
My only concern now is how much weight and stress the manifold with 3 heads filled with water will put on the sch 80 tee. I could ghetto it with zip ties, but personally I want things looking neat and tidy even in the cabinet sump. Will have to solve this later. Just need everything running again as I'm adding more fish to get ahead of the ich management part of my goal.

 

[cyberCoder]

Hi

I have the same question. Can I set up another return pump in the sump and go through the UV with close loop but output back to the sump's return area?

This way I can use the second pump to control the flow rate?