UV sterilizer plumbing

[DmitryB]

So my IM 170 INT is arriving on Monday (excited and terrified here.) Plumbing is something I know next to zero about. I'm told plumbing the IM tanks is easy because everything is pre-cut for you, etc. Let's hope! But now the other big plumbing question is going to be: UV Sterilizer. What in the world do I do with that?! I've tried to find videos online and there's surprisingly nothing (at least that I could find) that is a step-by-step tutorial. I guess I understand the basic principle: a pump sends water into the sterilizer and then the water comes out the other end. But I don't want that water to end up on the floor! So... I'm gonna need help to figure out what to get and where it goes!

I got a LifeGard 90W 3'' sterilizer (somewhat oversized for my tank because I want it to kill parasites dead) and Quiet One DC Pump 1,1888 GPH. I'll decide where exactly in the stand it goes once the stand is here, but somewhere in the back. Anybody know if this sterilizer can be mounted horizontally OR vertically or only horizontally?

- I found in an old thread here a link to some a barb package I'll need to go from 2'' to 3/4''. (Seems like a huge drop, doesn't it?) But aside from that - what else am I gonna need? A 3/4'' PVC to go from the pump (flexible PVC?) into the sterilizer. And then a PVC to go from sterilizer back into the sump. (I've read ideally water goes right into the display, but not sure that's practical.) What kind of connects and valves do I need? 90 elbows, 45 elbows? Where does the pump go? Before or after the skimmer? (There'll be a refugium after the skimmer). Then water returns into the return chamber?

This is all a lot and I appreciate all the help! Talk to me like I'm 5 years old.

 

[UncommonSense]

I got a LifeGard 90W 3'' sterilizer (somewhat oversized for my tank because I want it to kill parasites dead) and Quiet One DC Pump 1,1888 GPH

For starters, are you confident this sterilizer has an inlet and outlet designed for 3” pipe? — this BRS description lists 2”!

https://www.bulkreefsupply.com/90-watt-pro-max-high-output-uv-sterilizer-lifegard-aquatics.html

Anybody know if this sterilizer can be mounted horizontally OR vertically or only horizontally?

From the above listing:

“The outlets can be positioned in several different directions to fit your available space and plumbing setup without any additional plumbing”

This doesn’t directly answer your question, but It leads me to believe it can be mounted horizontally or vertically!

I found in an old thread here a link to some a barb package I'll need to go from 2'' to 3/4''.

this is a common trap! Let me explain:

— 3/4” (inside diameter) tubing has to go into a 3/4” barbed fitting, which has in inside diameter very close to 1/2”… you’ll be lucky to get 600gph through a 3/4” barbed fitting! (Simply put, you have to go one size larger with tubing than with pipe to achieve similar flow rates!)

— as you can see above, the algae flow rate for this massive sterilizer is 2,800gph max… weirdly, they do not list a minimum flow rate at all, much less a flow rate for multi-cellular organisms (like some waterborne parasites)…

— this said, I do know a 15W Lifegard sterilizer has a minimum safe flow rate of 150GPH… the scale is not linear, but this means your 90W unit needs roughly 900GPH of water flow at minimum! (50% more than can even be reasonably expected to flow through 3/4” tubing!)

And then a PVC to go from sterilizer back into the sump. (I've read ideally water goes right into the display, but not sure that's practical.)

It is very practical in your application! In fact, your return pump should run right around that 900GPH minimum UV flow rate if left unrestricted (plumbing diameter-wise)!

This is the only thing I can find which even resembles a flow curve for this pump; the delineations appear to be translated from metric, but a bit of reading in puts you at roughly 920GPH (observed) flow from that pump with 4-4.5ft of vertical well height creating flow loss, (assuming plumbing isn’t restrictive!)

I would definitely vote for running 100% of the return pump’s water through the UV sterilizer, probably using 1.25” tubing, or 1” pipe at minimum! (It can be wise to reduce from the 2-3” pipe size on the UV to maybe 1.5” threaded, then reduce again from there to your final size so you don’t have to cut anything out later to do a plumbing diameter upgrade)

What kind of connects and valves do I need? 90 elbows, 45 elbows?

No valves needed… maybe a few unions, reducer bushings, and your choice of tubing or pipe (sized correctly so that return pump can flow sufficient water through the UV sterilizer to keep it cool)

 

[Ecvernon]

I use something similar to this when i plumbed mine.

https://www.masterspapartsonline.co...nt=&utm_term=4581458815938042&utm_content=All

 

[DmitryB]

For starters, are you confident this sterilizer has an inlet and outlet designed for 3” pipe? — this BRS description lists 2”!

https://www.bulkreefsupply.com/90-watt-pro-max-high-output-uv-sterilizer-lifegard-aquatics.html

From the above listing:

“The outlets can be positioned in several different directions to fit your available space and plumbing setup without any additional plumbing”

This doesn’t directly answer your question, but It leads me to believe it can be mounted horizontally or vertically!



this is a common trap! Let me explain:

— 3/4” (inside diameter) tubing has to go into a 3/4” barbed fitting, which has in inside diameter very close to 1/2”… you’ll be lucky to get 600gph through a 3/4” barbed fitting! (Simply put, you have to go one size larger with tubing than with pipe to achieve similar flow rates!)

— as you can see above, the algae flow rate for this massive sterilizer is 2,800gph max… weirdly, they do not list a minimum flow rate at all, much less a flow rate for multi-cellular organisms (like some waterborne parasites)…

— this said, I do know a 15W Lifegard sterilizer has a minimum safe flow rate of 150GPH… the scale is not linear, but this means your 90W unit needs roughly 900GPH of water flow at minimum! (50% more than can even be reasonably expected to flow through 3/4” tubing!)



It is very practical in your application! In fact, your return pump should run right around that 900GPH minimum UV flow rate if left unrestricted (plumbing diameter-wise)!

This is the only thing I can find which even resembles a flow curve for this pump; the delineations appear to be translated from metric, but a bit of reading in puts you at roughly 920GPH (observed) flow from that pump with 4-4.5ft of vertical well height creating flow loss, (assuming plumbing isn’t restrictive!)

I would definitely vote for running 100% of the return pump’s water through the UV sterilizer, probably using 1.25” tubing, or 1” pipe at minimum! (It can be wise to reduce from the 2-3” pipe size on the UV to maybe 1.5” threaded, then reduce again from there to your final size so you don’t have to cut anything out later to do a plumbing diameter upgrade)



No valves needed… maybe a few unions, reducer bushings, and your choice of tubing or pipe (sized correctly so that return pump can flow sufficient water through the UV sterilizer to keep it cool)

- You are right that the fitting is 2''. The body is 3''. And they do seem vague about the positioning, so I'll assume for now it can go in any configuration. (I may try to contact them to confirm.) Also reading old threads it seems Aquagard never mentioned the minimum flow; people have been discussing that for literally years!

- With the fittings - I can go down to 1.5''. Is it not ok to say at 1.5''? So I'm thinking I'd get a flexible hose to come out of the pump (just easier to maneuver flexible) at 2'' and then reduce down to hard PVC either 1.5 or 1.25'' before it enters the UV. Then out of the UV go from 2'' to 1.5/1.25'' out into.... try to get it directly into the tank or into the return chamber where the return pump (VarioS 10) would send everything into the tank? Sending UV up to the tank directly may be tricky because the back of my tank will be visible from the sides. One reason I went with an INT build is to keep the pipes out of view.

 

[UncommonSense]

With the fittings - I can go down to 1.5''. Is it not ok to say at 1.5''? So I'm thinking I'd get a flexible hose to come out of the pump (just easier to maneuver flexible) at 2'' and then reduce down to hard PVC either 1.5 or 1.25'' before it enters the UV. Then out of the UV go from 2'' to 1.5/1.25'' out into.... try to get it directly into the tank or into the return chamber where the return pump (VarioS 10) would send everything into the tank? Sending UV up to the tank directly may be tricky because the back of my tank will be visible from the sides. One reason I went with an INT build is to keep the pipes out of view.

The only reasons to use 1.25” tubing over say, 1.5-2” tubing would be because it’s not as expensive, and not as bulky/stiff!

Hard PVC would only need to be 1”, this is a case where it’s important to reduce the sterilizer's inlet/outlet to 1.5” threaded, then reduce again to 1”! (It basically means you unscrew the 1” reducer in the future and have full 1.5” plumbing without cutting anything out of your plumbing [pipe cement is permanent!])

 

[DmitryB]

Ok so 1'' will be enough for the needed flow and I should get basically everything threaded so it can be easily removed in the future? (Is threaded less secure? Do you use plumbing tape on the threads or anything like that?)

What's a good length to have of tubing before reducing? Is there a preferred minimum before lowering the flow? (Also, would a valve not work to reduce flow? Better to reduce with fittings and smaller pipes?)

 

[BryanM]

I've read before where the UV manufacturers prefer them to be installed vertically with the inlet on the bottom, basically to make sure the entire vessel is full of water. If you install them horizontally there's apparently ways that it can not be 100% full.

Solid advice to reduce twice, I'm in a situation where I glued my reducers in and now want to change plumbing.... Its not pleasant, and the fittings in my case are quite expensive.

 

[UncommonSense]

Ok so 1'' will be enough for the needed flow

1” Schedule 40 (white) PVC pipe is sufficient for this flow rate, 1.25” tubing will be necessary to match 1” pipe flow rates!

I should get basically everything threaded so it can be easily removed in the future?

No you should only really need threads where adapting to a barbed fitting, or for the reducers you cement into the UV sterilizer’s inlet/outlet!

Threads do mean you can disassemble down the road, but threaded pipe is all thick walled, thus flows less… pipe cement will be required for the slip X thread reducing bushings you cement into the UV sterilizer at the very least, so you might use it for some lengths of rigid PVC pipe, too!

Is threaded less secure? Do you use plumbing tape on the threads or anything like that?

Technically, the thread groove is a leakage path, so by definition, national pipe thread (NPT) isn’t as secure as a cemented joint!

Given this mechanical leak path built right in, you do want to use a thread sealant! Teflon tape is actually intended for metal pipe threads… it will typically work on plastic threads anyways, but the proper way is using a paint-on or rub-on thread sealant!

What's a good length to have of tubing before reducing? Is there a preferred minimum before lowering the flow? (Also, would a valve not work to reduce flow? Better to reduce with fittings and smaller pipes?)

Your plumbing shouldn’t be increasing and decreasing in size anywhere it isn’t absolutely necessary, you’ll run 1.25” tubing, or 1” schedule 40 PVC pipe the whole way, simply reducing down to it at the UV inlet/outlet!

A valve does work to reduce flow, in exactly the same way restrictive plumbing reduces flow! — the pump cannot tell the difference!

On to the pump, it's DC, thus has flow control built right in! Turning the pump down is more power efficient than throttling via flow restriction! (Though you really do want this 1188GPH pump running at full throttle to keep this massive UV cool!

 

[DmitryB]

I'm going to draw a diagram and post later for confirmation of all that needs to be done and what I'll need!

I got this sterilizer through ReefBySteele. I just read through my emails with Kent and he said in his first message that "for total kill this UV sterilizer maximum flow is 375-610 GPH." Does this sound right? Based on that number he recommended this particular pump.

I'm a bit confused on the various numbers for maximum flow. The UV product page says its max flow rate is 4,600 gph. Max flow for algae and bacteria is 2,800 gph. What are these other gph numbers and where does 375-610 come in?? Is this taking into account upward water movement if the return goes several feet up into the tank? What if the outflow is into the return chamber which is basically at the same level?

 

[Privateye]

I'm going to draw a diagram and post later for confirmation of all that needs to be down and what I'll need!

I got this sterilizer through ReefBySteele. I just read through my emails with Kent and he said in his first message that "for total kill this UV sterilizer maximum flow is 375-610 GPH." Does this sound right? Based on that number he recommended this particular pump.

I'm a bit confused on the various numbers for maximum flow. The UV product page says its max flow rate is 4,600 gph. Max flow for algae and bacteria is 2,800 gph. What are these other gph numbers and where does 375-610 come in?? What a this taking into account upward water movement if the return goes several feet up into the tank? What if the outflow is I to the return chamber if the dump which is basically at the same level?

"Total kill" isn't a term used with UV sterilizers (they deal with "log reduction" and don't claim to impact all microbes). Honestly, Lifegard isn't great at providing or even having information. Even if you call them, they know little. I currently use 4 of these units and I'm not the biggest fan. They cannot even tell you how it goes together. I had replaced an o-ring and the unit would not seal when I followed the diagram. They referred me to a video where the guy ran into the same problem, then stopped filming. I got it to work perfectly (for years) by deviating from the instructions and moving the o-ring to a different location. The whole "roll up the wire and insert it into the quartz sleeve" thing was an annoying feature too. My biggest complaint is their method of protecting the housing from the UV light though - some sacrificial plastic shoved inside it that you need to change annually (since it will degrade). And when you go to change it that plastic has fused to the housing, so you need to chip it out in pieces with a screwdriver.

I believe they're telling you to run it at a reduced flow rate to combat "parasites". The slower the flow rate, the longer the microbes sit in front of the lamp, and the larger the UV dose they receive. In theory you'd get a high UV dose if the unit got a flow rate of 1 drop per hour, but the rate at which you'd sterilize the microbes is slower than their rate of replication. That's where the tank volume and turnover rate factors in. You run higher flow rates for algae because it replicates quickly, and slower flow rates for parasites to ensure you get the high UV dose they require. A unit that delivers a UV dose suitable for parasites will also sterilize algae at the same time. Enough of your water also has to go through it to impact the overall population though.

While I was looking at the performance specs earlier I basically drew the same conclusion you did: "okay, they say what UV dose this unit can provide, but not the flow rate at which it's provided". The higher the flow rate, the lower the dose.

And regarding head pressure, it's more than just the vertical lift. Uncommonsense is right that you wouldn't want your plumbing to be too restrictive, or it will affect the flow rate. It's much easier to blow through a paper towel tube than a coffee stirrer, for example. There is friction as water (or gas) moves through a pipe. I don't know this tank very well, so I played around with some test numbers in this calculator:

Feel free to adjust it to more-real numbers, but in my example the head pressure is about 2' higher than the vertical lift due to friction, with 1" PVC pipe. Fewer fittings, less lift, slower flow rates, and shorter pipe length will reduce the head pressure.

I use that calculator all the time. It's a good one to bookmark.

 

[DmitryB]

I'm going to draw a diagram and post later for confirmation of all that needs to be down and what I'll need!

I got this sterilizer through ReefBySteele. I just read through my emails with Kent and he said in his first message that "for total kill this UV sterilizer maximum flow is 375-610 GPH." Does this sound right? Based on that number he recommended this particular pump.

I'm a bit confused on the various numbers for maximum flow. The UV product page says its max flow rate is 4,600 gph. Max flow for algae and bacteria is 2,800 gph. What are these other gph numbers and where does 375-610 come in?? What a this taking into account upward water movement if the return goes several feet up into the tank? What if the outflow is I to the return chamber if the dump which is basically at the same level?

"Total kill" isn't a term used with UV sterilizers (they deal with "log reduction" and don't claim to impact all microbes). Honestly, Lifegard isn't great at providing or even having information. Even if you call them, they know little. I currently use 4 of these units and I'm not the biggest fan. They cannot even tell you how it goes together. I had replaced an o-ring and the unit would not seal when I followed the diagram. They referred me to a video where the guy ran into the same problem, then stopped filming. I got it to work perfectly (for years) by deviating from the instructions and moving the o-ring to a different location. The whole "roll up the wire and insert it into the quartz sleeve" thing was an annoying feature too. My biggest complaint is their method of protecting the housing from the UV light though - some sacrificial plastic shoved inside it that you need to change annually (since it will degrade). And when you go to change it that plastic has fused to the housing, so you need to chip it out in pieces with a screwdriver.

I believe they're telling you to run it at a reduced flow rate to combat "parasites". The slower the flow rate, the longer the microbes sit in front of the lamp, and the larger the UV dose they receive. In theory you'd get a high UV dose if the unit got a flow rate of 1 drop per hour, but the rate at which you'd sterilize the microbes is slower than their rate of replication. That's where the tank volume and turnover rate factors in. You run higher flow rates for algae because it replicates quickly, and slower flow rates for parasites to ensure you get the high UV dose they require. A unit that delivers a UV dose suitable for parasites will also sterilize algae at the same time. Enough of your water also has to go through it to impact the overall population though.

While I was looking at the performance specs earlier I basically drew the same conclusion you did: "okay, they say what UV dose this unit can provide, but not the flow rate at which it's provided". The higher the flow rate, the lower the dose.

And regarding head pressure, it's more than just the vertical lift. Uncommonsense is right that you wouldn't want your plumbing to be too restrictive, or it will affect the flow rate. It's much easier to blow through a paper towel tube than a coffee stirrer, for example. There is friction as water (or gas) moves through a pipe. I don't know this tank very well, so I played around with some test numbers in this calculator:

Feel free to adjust it to more-real numbers, but in my example the head pressure is about 2' higher than the vertical lift due to friction, with 1" PVC pipe. Fewer fittings, less lift, slower flow rates, and shorter pipe length will reduce the head pressure.

I use that calculator all the time. It's a good one to bookmark.

This is all great info, thanks! Did you mount these vertically? And the flow has to go from bottom up, right? Doesn't that mean that from the pump to get into the bottom of the UV water has to travel up and over the sump wall, then down and sideways into the UV, and then the reverse to go back into the sump/display? So we have to add all these turns to the flow that will impact head pressure. (Am I even using the term "head pressure" correctly? lol)

For flexible PVC, which is easier to work with, is it as reliable as hard PVC? I love read that clear flex PVC can grow mold, but they do seem to make black flex PVC, which might eliminate this risk?

I'm working on the diagram; total amateur hour!

 

[UncommonSense]

Does this sound right? Based on that number he recommended this particular pump.

It definitely doesn’t sound unreasonable! I’d imagine that 6-10GPM (360-600gph) is plenty to keep this UV bulb from overheating..

The UV product page says its max flow rate is 4,600 gph. Max flow for algae and bacteria is 2,800 gph. What are these other gph numbers and where does 375-610 come in??

These numbers are fairly meaningless as presented by the manufacturer to be honest… 4,600gph is basically maxing out 2” plumbing, 2,800gph is the maximum flow rate where unicellular organisms such as waterborne algae can be sterilized in a single-pass! (It's basically measurement of water dwell time in exposure to UV-c)… the relatively low flow rate used for waterborne parasite control is due to them being multi-cellular… (and, UV isn’t particularly effective against some types of parasites!)

Is this taking into account upward water movement if the return goes several feet up into the tank? What if the outflow is into the return chamber which is basically at the same level?

This pump was recommended because it is sized well for The lowest flow range (for multi-cellular organism sterilization) of this UV! You’d turn the pump down if plumbing sump to sump, or leave the pump at 70% + if all of water is going back to the display!

And the flow has to go from bottom up, right? Doesn't that mean that from the pump to get into the bottom of the UV water has to travel up and over the sump wall, then down and sideways into the UV, and then the reverse to go back into the sump/display? So we have to add all these turns to the flow that will impact head pressure.

Bottom-up is ideal, any air bubbles that get into the UV housing burp themselves back out of it that way!

The only thing you’re looking at with head pressure is “how far out of water are you lifting water vertically?”

— distilled water creates .433PSI per-vertical foot of water column…

— there are some silly nuances to this, but in general, if the entire plumbing assembly is full of water, it only takes extra work to lift that water up vertically above the sump/plumbing water line! (See the above flow curve photo for an example; the pump will move less and less water volume per-hour as it has to lift that water further and further… up to the point where it “dead heads”, unable to flow any water due to vertical height it’s trying to lift! (This is identical to what happens when you close a valve on a running pump’s outlet; the pump just acts like it’s encountering way more head pressure!)

For flexible PVC, which is easier to work with, is it as reliable as hard PVC? I love read that clear flex PVC can grow mold, but they do seem to make black flex PVC, which might eliminate this risk?

You get weird stuff growing in plumbing no matter what you choose… I will say that some brands of flexible tubing do leech metals out into water (plasticizer additives)… I’ve had my best luck using a short length (~6”) of silicone tubing on the return pump outlet, then adapting to rigid PVC from there on out! (The silicone tubing is a vibration mitigator)

 

[DmitryB]

Ok here's my diagram as I understand the plumbing - if it flows out into the return chamber. I numbered each step for easy reference. Am I on the right track?

 

[UncommonSense]

Ok here's my diagram as I understand the plumbing - if it flows out into the return chamber. I numbered each step for easy reference. Am I on the right track?

This is a great start!

I should have asked earlier: what is the plumbing diameter of the return bulkhead(s) on this tank?

— I ask because it makes sense to either plumb to that size, or to leave room to plumb to that size later, should you desire!

 

[DmitryB]

Only a start?! lol

Here are the specs on the tank and the sump. Seems to be a mix of 3/4 and 1".

 

[UncommonSense]

Only a start?! lol

Here are the specs on the tank and the sump. Seems to be a mix of 3/4 and 1".

Ah! Interesting… a single 3/4” return on a 170G system seems a tad underwhelming, but it will work!

Basically, you’re stuck at ~700-800gph maximum observed return plumbing flow due to the restrictive return bulkhead fitting…

It’s still sufficient to make the above plumbing arrangement work, it just changes plumbing sizes!

— assuming you run this UV inline on the return plumbing (best bet; ensures 100% of water gets sterilized on each pass) You may want to run a accessory item like a reactor off your return pump later, so I’d still recommend the 1” rigid PVC pipe, for everything up to the bulkhead, where you’ll reduce to 3/4” through one of numerous methods!

— the UV sterilizer could benefit from a pair of 2”-1.5” slip X NPT reducer bushing (NPT on inside) , before a second reducing bushing from 1.5”-1” which is either NPT or slip on the inside! (This prevents you from painting yourself into a corner plumbing size-wise, should you ever want to install this UV on a bigger tank later! [and not buy new UV sterilizer inlet/outlet plumbing because the cemented single 2”-1” reducing bushings in the originals reduced too much for your new needs!])

 

[mmorrison55]

The lifegards have that nice sweeping opening and exit to facilitate flow, so I personally would recommend installing it horizontally to reduce the need for 90 degree fittings in and out of the sterilizer.

 

[mmorrison55]

Also, is your pump thats feeding the uv a secondary pump or the pump you will use for your returns?

 

[DmitryB]

Ah! Interesting… a single 3/4” return on a 170G system seems a tad underwhelming, but it will work!

Basically, you’re stuck at ~700-800gph maximum observed return plumbing flow due to the restrictive return bulkhead fitting…

It’s still sufficient to make the above plumbing arrangement work, it just changes plumbing sizes!

— assuming you run this UV inline on the return plumbing (best bet; ensures 100% of water gets sterilized on each pass) You may want to run a accessory item like a reactor off your return pump later, so I’d still recommend the 1” rigid PVC pipe, for everything up to the bulkhead, where you’ll reduce to 3/4” through one of numerous methods!

— the UV sterilizer could benefit from a pair of 2”-1.5” slip X NPT reducer bushing (NPT on inside) , before a second reducing bushing from 1.5”-1” which is either NPT or slip on the inside! (This prevents you from painting yourself into a corner plumbing size-wise, should you ever want to install this UV on a bigger tank later! [and not buy new UV sterilizer inlet/outlet plumbing because the cemented single 2”-1” reducing bushings in the originals reduced too much for your new needs!])

I basically have no idea what any of that means.

Was my diagram inline on the return plumbing?? I have no idea. I was going to place the pump for the UV before or after the skimmer. (But remember, there's a planned refugium chamber after the skimmer.) Are you saying that I should remove the return pump in the last chamber and have all water coming out of the UV go into the 3/4'' pipe going back into the tank? Essentially the pump pushing water into the UV is also then pushing it into the tank?? Where would the pump for the UV go in the sump? And if I'm understanding this correctly, what are the risks of getting rid of the dedicated return pump?

 

[DmitryB]

Also, is your pump thats feeding the uv a secondary pump or the pump you will use for your returns?

I did plan to have a separate pump in the return chamber sending water into the tank. (VarioS 10; the tank comes with a MightyJet XL.)

On the positioning of the UV unit itself: besides the intricate piping sending water up and down, are there other risks/benefits to vertical vs. horizontal?

Also are those union joints on the sterilizer? Does it mean I could put a reducer bushing there directly?