UV sterilizer plumbing

[DmitryB]

I'm making a list of connections I will need. Let me know what I may be missing. (I don't know yet the qua Tory of each, but at least I want to get a good idea of what I need to get.)

- 90 bends
- 45 bends
- bushings 2" to 1"
- bushings 1" to 3/4"
- T fittings (with valves to shut off/redirect flow if I want to have an alternate path to send water into tank without sterilizer?)
- unions 1" and 3/4"
- 2" PVC
- 1" PVC
- 3/4" PVC
- 3/4" flexible PVC

 

[DmitryB]

Oh looking at the MightyJet XL, it has barbed fittings for 3/4, 1 and 1.25". So what if they go out of the pump at the higher 1.25 and only switch to 3/4 at the very end before going into the last flexible hose going into the tank? So the whole pathway from pump - through the sterilizer - and out stays at 1.25 and 2". (2" being the sterilizer fittings.) maybe remove 1" PVC out of the equation altogether?

 

[UncommonSense]

Oh looking at the MightyJet XL, it has barbed fittings for 3/4, 1 and 1.25". So what if they go out of the pump at the higher 1.5 and only switch to 3/4 at the very end before going into the last flexible hose going into the tank? So the whole pathway from pump - through the sterilizer - and out stays at 1.25 and 2". (2" being the sterilizer fittings.) maybe remove 1" PVC out of the equation altogether?

You can do it this way, but you’re still stuck with the 3/4” plumbing going through the tank bottom, meaning it would be much more expensive parts for the same flow result!

1” rigid plumbing with 1.25” tubing will flow more than that particular 3/4” bulkhead can take, so there’s no reason to go bigger on plumbing diameter unless you’re specifically running a manifold off the return pump plumbing as well! (The 2” plumbing on this sterilizer is for the likes of a multi-thousand thousand gallon pond!)

 

[Privateye]

I think it's important to remember that flow through an orifice at a given pressure is not the same as the head pressure produced by that flow rate going through the orifice. The former looks more restrictive, but it's not what we're talking about in this situation.

I also think it's important to mention that an orifice just refers to the opening it goes through, but not a length of pipe. A length of pipe will produce more friction because friction is accumulated over a larger surface area.

I could not test exactly what you requested in the span of time I had, but I used what I had. It was a reservoir of RO water, with a magnetic drive pump attached (Iwaki WMD40-RLT), and the outlet was at about the same level as the water in the reservoir. The pump is capable of producing 9.3 PSI and the max flow rate is 14 gpm. I didn't have 3/4" plumbing on it though. I had 2-3 feet of 1" PVC (with a 90, three 45's, and a tee fitting), connected to a 3/4" GHT fitting, connected to 8' of 5/8" ID (0.625") garden hose. This is more-restrictive than 3/4". Human error is involved when eyeballing the 5 gallon mark on a bucket, but it took 24 seconds to fill by my eye. This is a flow rate of 12.5 gpm. This diameter is between those listed on your chart, but close to the range you have for 1/2". So based on your chart I should get closer to 7 gpm than 11 gpm, but I got more than either. It concurs with the head loss calculator I linked though.

Or, you could reference one of the very frictional loss charts you’ve mentioned (which are also themselves intended for large runs of higher pressure plumbing!)

Note that the 3/4” category physically ends, even at much higher water pressures that any residential aquarium pump produces, before the 34GPM the calculator you presented claims 3/4” plumbing can achieve at <6PSI…

Yes, I would not recommend 100' of 3/4" pipe as per those frictional loss charts. Shorter lengths produce less head pressure though, so if it isn't suitable for 100' it doesn't mean that it isn't usable for, say, an orifice. I don't know of any residential aquariums with a 100' run of pipe either.

If you were to use an aquarium pump, which as you mentioned produces lower pressures than the chart shows, it doesn't mean it won't pump anything through 100' of 3/4" pipe. It will pump less water than 34 gpm, which means it will not experience the same pressure. Once the pressure and flow rates of the chart match the same pressure and flow on the performance curve of a pump, that's how you can expect it to perform with 100' of 3/4" pipe.

I sized pumps and associated equipment (e.g. filters, chillers, UV sterilizers, etc.) at work for a few years, with max flow rates from 1-2000 gpm. I would have known long ago if my methods were incorrect. I feel pretty confident that your chart is either incorrect, or we're missing something about it.

I think the suction side of the pump is just one of the potential situations they're listing in the green category. It would be weird for them to display two columns of suction info and four columns of discharge info. It might just be that they're acknowledging you can't have a suction pressure above about 15 PSI due to physics/cavitation.

Okay, I played ball and now I'm passing it to you. Try your own flow measurements at home and compare them to your chart! You might also find that they are different.

 

[DmitryB]

Oh looking at the MightyJet XL, it has barbed fittings for 3/4, 1 and 1.25". So what if they go out of the pump at the higher 1.5 and only switch to 3/4 at the very end before going into the last flexible hose going into the tank? So the whole pathway from pump - through the sterilizer - and out stays at 1.25 and 2". (2" being the sterilizer fittings.) maybe remove 1" PVC out of the equation altogether?

You can do it this way, but you’re still stuck with the 3/4” plumbing going through the tank bottom, meaning it would be much more expensive parts for the same flow result!

1” rigid plumbing with 1.25” tubing will flow more than that particular 3/4” bulkhead can take, so there’s no reason to go bigger on plumbing diameter unless you’re specifically running a manifold off the return pump plumbing as well! (The 2” plumbing on this sterilizer is for the likes of a multi-thousand thousand gallon pond!)

Understood!

With flexible PVC - which I'll need some of to come out of the pump and some extra to go into the tank (it does come with some hosing), is sizing not the same vs hard pipe? So if I wanted 1" - do I go with 1" flexible?

 

[Privateye]

Understood!

With flexible PVC - which I'll need some of to come out of the pump and some extra to go into the tank (it does come with some hosing), is sizing not the same vs hard pipe? So if I wanted 1" - do I go with 1" flexible?

The sizing is the same for PVC fittings and such.

Technically there's a special cement for flexible PVC, but a lot of old timers will say that the regular PVC cement is fine too. I haven't used either on flexible PVC myself, but I've used systems and hoses with flexible PVC made by those old timers. I've never seen an issue.

 

[DmitryB]

Ok so - I made a Photoshop diagram of the install proposal. Please give feedback! On bushings. I should probably have some unions in there too??

AND would it be easier to have flexible PVC the whole way vs. hard PVC? Flexible you may not need this many 90 elbows... Assuming Flex PVC is as safe as hard PVC.

 

[Krux]

flex pvc is not as flexible as you may imagine... to reduce friction see where you may be able to work in sweeps in place of 90s. I would also consider silicone tubing for the 3/4" section.

 

[Privateye]

Is the UV going to be mounted in that orientation? Most of them need to be installed with the ports facing up (for horizontal installations) or the inlet on the bottom and the outlet on top (for vertical installations).

This allows the unit to evacuate air, which would otherwise lower the dosage (because there's less water in the vessel at any given time) and potentially damage it. The layer of water between the lamp and the housing is part of the housing's protection from the UV light itself. There are some UV sterilizers where the mounting orientation isn't affected by this, such as the Coralife TurboTwist, because the water spirals around the lamp.

It would still run, you just don't know what dose you're getting and you'd probably void your warranty. They don't mention this in their manual though, so maybe you'd be able to make a case for replacement if it came to that. There's the sacrificial sleeve too, which will help protect the housing. Maybe it's enough.

 

[DmitryB]

Is the UV going to be mounted in that orientation? Most of them need to be installed with the ports facing up (for horizontal installations) or the inlet on the bottom and the outlet on top (for vertical installations).

This allows the unit to evacuate air, which would otherwise lower the dosage (because there's less water in the vessel at any given time) and potentially damage it. The layer of water between the lamp and the housing is part of the housing's protection from the UV light itself. There are some UV sterilizers where the mounting orientation isn't affected by this, such as the Coralife TurboTwist, because the water spirals around the lamp.

It would still run, you just don't know what dose you're getting and you'd probably void your warranty. They don't mention this in their manual though, so maybe you'd be able to make a case for replacement if it came to that. There's the sacrificial sleeve too, which will help protect the housing. Maybe it's enough.

Oh I didn't realize that was the wrong position. I kind of assumed the brackets were for housing above the sump. If it has to be flipped, that means even more 90 elbows!

 

[jonelder68]

Here’s how I did mine…

The return is cut by 50% through a ball valve and diverted to the UV. If you run UV through return pump I highly suggest having the return on a battery back up to prevent cooking your UV bulb if you ever loose power.

 

[DmitryB]

Here’s how I did mine…

The return is cut by 50% through a ball valve and diverted to the UV. If you run UV through return pump I highly suggest having the return on a battery back up to prevent cooking your UV bulb if you ever loose power.

My goal was to have the return pump and heaters run through a battery just for power outages, which I get a fair amount of.

Unfortunately I can't fit my UV vertically, it has to go horizontally.

Do you have a diverter there? One thing I was wondering about was installing some kind of diverter in case I want to bypass the UV at any point.

 

[DmitryB]

flex pvc is not as flexible as you may imagine... to reduce friction see where you may be able to work in sweeps in place of 90s. I would also consider silicone tubing for the 3/4" section.

I wish they made 180 degree schedule 40 or 80 PVC. (Do they?) that would be gentler on the flow than two 90 degrees.

Also, silicone not flex PVC?

 

[jonelder68]

I wish they made 180 degree schedule 40 or 80 PVC. (Do they?) that would be gentler on the flow than two 90 degrees.

Also, silicone not flex PVC?

Look at my previous post/picture. You can buy long sweep 90s from pvconline or supply house that drastically help with flow rates.

 

[jonelder68]

My goal was to have the return pump and heaters run through a battery just for power outages, which I get a fair amount of.

Unfortunately I can't fit my UV vertically, it has to go horizontally.

Do you have a diverter there? One thing I was wondering about was installing some kind of diverter in case I want to bypass the UV at any point.

Yes. See all three ball valves. I can run full or partial flow through uv or completely bypass uv and run just return. Mainly for if I ever need to service uv I don’t have to shut return off.

 

[DmitryB]

Yes. See all three ball valves. I can run full or partial flow through uv or completely bypass uv and run just return. Mainly for if I ever need to service uv I don’t have to shut return off.

Is this where the water comes in from the tank and splits between direct to tank and into the UV? If you shut off the valve on the right side, that will stop water from going into the UV? And if you shut off valve on top as well, you can service the UV and water keeps flowing directly back into tank? And if you shut off the valve on the left, 100% of the water will go into the UV?

Also, I just tried and I actually can install the UV in my stand vertically. Although service it, I'd have to remove it. If it's mounted horizontally, I can swap out bulbs without removing it (there is a side door on the stand.)

There is also room to install it horizontally on the bottom of the stand. So 3 placement options...

 

[jonelder68]

Is this where the water comes in from the tank and splits between direct to tank and into the UV? If you shut off the valve on the right side, that will stop water from going into the UV? And if you shut off valve on top as well, you can service the UV and water keeps flowing directly back into tank? And if you shut off the valve on the left, 100% of the water will go into the UV?

Also, I just tried and I actually can install the UV in my stand vertically. Although service it, I'd have to remove it. If it's mounted horizontally, I can swap out bulbs without removing it (there is a side door on the stand.)

There is also room to install it horizontally on the bottom of the stand. So 3 placement options...

Yes it’s exactly how it’s plumbed.

Mounting doesn’t specifically matter vertical vs horizontal. Horizontal will hold water even with return pump off. So take that into account for servicing.

 

[Krux]

I wish they made 180 degree schedule 40 or 80 PVC. (Do they?) that would be gentler on the flow than two 90 degrees.

Also, silicone not flex PVC?

flex pvc comes off a giant roll and will hold the curve basically forever, it can not truly be flexed into contorted shapes. I would describe it as semi-rigid not flexible. Silicone can actually be bent to meet your needs making plumbing connections easier, removes vibration, and will not force your plumbing back into the macaroni shape it desires to be in over time. All you need is a foot of it to make your life easier.

 

[vittpsu21]

:( I am just starting down this path and this entire thread has given me anxiety. I had planned to just run the uv inline

pump --->flex line into UV --->into hard plumbing return that currently has the flex from the return running into it.

Is this not adequate? lol I ordered a different UV but this thread indicates I might have to do more lol

 

[Krux]

:( I am just starting down this path and this entire thread has given me anxiety. I had planned to just run the uv inline

pump --->flex line into UV --->into hard plumbing return that currently has the flex from the return running into it.

Is this not adequate? lol I ordered a different UV but this thread indicates I might have to do more lol

I see no reason your plan with not work, you just need the water to pass through it. As with many things it can be as complicated as you desire, but doesn't need to be elaborate to get the job done.