UV sterilizer help.

[fellterrier]

I’m trying to figure out the best way to install a UV for my new 300 gallon tank build. Option A would be with its own pump in the skimmer chamber of my sump with the water being dumped into the return pump area or Option B which would utilize a manifold coming off the return pump into the skimmer then back to the pump return chamber or lastly, Option C which would utilize a Y connection coming off the return line going to the sump then to the skimmer then to the return chamber. Thoughts?

 

 

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[malacoda]

Of those three, option A would be best.  Reason being, it will be the most efficient of the three you've listed, and send the largest volume of 'sterilized' water back to your DT. 

 

With Options B & C, some of the sterilized water will just keep getting sent back through the sump again, and again, and again, before it ever reaches your DT. So, with Options B & C, in essence, you'll primarily be sterilizing sump water ... and only a portion of it will ever make it back to the DT.

 

That said, the most optimal way to plumb in a UV is to take water directly from the DT, send it through the UV, then straight back to the DT. (E.g. Have the UV on its own closed loop from/to the DT.)

 

The second most efficient and effective way to plumb it would be to take water from the return line, pass it through the UV, then send it into the DT.

 

The third would be Option A on your list, take water from the start of the sump, send it through UV, then discharge it into the return section of the sump so that the return pump sends it to the DT.

 

 

 

Edited February 2, 2020 by malacoda

[fellterrier]

Than


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[fellterrier]

Thanks for the input. With Option C I think I misspoke. What I was trying to say, was with a Y pipe coming off the return line going into the sump, controlled with a ball valve, divert water to the UV then to the return chamber back to the display.


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[fellterrier]

Option C would treat the Water with UV without it going into sump . The water would go from the UV to the return pump chamber.


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[davelin315]

Actually, I think this question is very hard to answer without knowing your return pump and the size UV sterilizer and flow through rating.  Minimum contact times are important to know for actual UV sterilization rather than clarification.

[malacoda]

Dave is right.  With no information other than what you provided, Option A would be better than Option B in terms of getting the most water to pass through the UV back into the DT ... versus just recirculating in the sump where it won't do as much good.

 

As for Option C, I'm not 100% sure I follow.  You're saying 'return line' to the sump, through UV, then through return pump back to DT.  Do you mean you want to put a Y pipe on your 'drain line' going into the sump with a ball valve to control the flow? If so, I'm not sure how having a split in the drain line, with a ball valve on one of the splits, will affect the flow through your overflow, or if a split feed off your drain line will put enough flow through the UV for the UV to be effective...

 

If you're not getting the proper amount of flow through the UV, it won't be effective no matter how you plumb it.

 

For example, I just plumbed in a 15 watt UV off of my return line (which then discharges into my DT).  I thought I would have plenty of flow out of the return pump to feed it. But, the change in head pressure from adding that UV line was enough so that with my return pump running at max (it's a controllable DC return pump), I just barely get the minimum flow through the UV per the UV manufacturer specs. If I want or need any more flow through the UV, I'll have to get a larger return pump.

 

In addition to checking the manual/FAQ page of the UV unit you've got to find out how much flow is recommended, this page might prove helpful as well:  How Aquarium and Pond UV-C sterilizers work

 

 

Edited February 2, 2020 by malacoda

[Origami]

First and foremost, you need to establish whether you're using the UV for clarification or sterilization. This sets your dosing objective and establishes the size requirement of the UV unit. It also puts you in the ballpark of what flow is needed assuming a certain turnover. Where the flow picks up or dumps out is of less concern as it doesn't really change the long term end point.

As for configurations, you'll have better control of flow rate with your Option A (separate pump).

AquaUV has a good chart that provides you a good starting point. I'll attach it here.

https://cloud.tapatalk.com/s/5e37349d9667a/UV-Charts-Salt-and-Fresh-Water-Web.pdf

[fellterrier]

Clarification. My return pump is a Vectra L2 rated at 3200 gph. The UV is a Lifeguard aquatics 55w. Per their instruction manual they recommend a flow rate of 2100 gph.


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[Origami]

Clarification. My return pump is a Vectra L2 rated at 3200 gph. The UV is a Lifeguard aquatics 55w. Per their instruction manual they recommend a flow rate of 2100 gph.

 

 

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That helps. Lifegard docs say that flow (2100 gph) delivers 30,000 uW/cm^2 with that unit. That's a level suitable for clarity in reef tanks, not sterilization. We often don't want to kill off beneficial microplankton so doses below sterilization levels are recommended in most cases.

 

The max recommended flow is 3600 gph with your unit. With head pressure (static and friction) your Vectra may not be delivering a full 3200 gph (which is max flow at 9 head pressure). It could be far less depending on your setup. Thus, you may find yourself in the operating sweet spot of your UV.

 

2100 gph is a bit of flow, though. If you can avoid a second pump, you can save on operating cost and added heat. You could run all your flow from the Vectra thru the unit, as long as the UV didn't add much dynamic head pressure. That UV unit looks like it has a large plumbing inlet and outlet, making me think it's probably low loss. In that case, if your Vectra flow is sufficient, you might just rote all your flow thru it directly avoiding ant loss-producing valves and such.

 

[Origami]

Another thought: Run all your main tank drain flow back thru the UV. No head pressure loss that way.

[fellterrier]

Thanks so much for the input. I’m thinking if I minimize all the bends I should be good to go with the setup flow wise.


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[fellterrier]

I’m using the Herbie method so main flow will be through the primary return and a secondary line with a trickle. You guys know the drill. I’m thinking direct flow through UV should work. Thanks for the input. Flow inside the tank will be two Mp40’s and 2 WAV Pumps so overall flow should suffice..


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[davelin315]

I feel like having a UV on the drain side would cause numerous issues.  If you are using an L2 and exercise any control over it your bean animal set up will have variable flow and the addition of a UV before or after the gate valve will cause additional adjustment issues that could result in noise.  Also, having the UV on the drain side could cause temperature to rise slightly and throw off your tank temperature.  While both of these things are probably pretty minimal in impact I would personally try to avoid any of these.

 

Of more serious consequence, which I am not sure is actually even a consequence, is that you are sterilizing the water coming out of the tank and returning potentially pathogen filled water back to the tank.  If your sump is home to lots of cryptocaryons, for example, they will settle there and when they bloom go back into your tank via the return.  If you had a UV on the return hitting all of the water then in theory you would have clean water going back to the tank.  The reality of this argument is probably that it doesn’t make a difference as the water gets all mixed together anyway but for some reason I just feel like it should be on the return side.  Now if you were to use two UV sterilizes, one on each side...

 

Last concern is that if power cuts off in the drain line and your UV is still running then it could overheat and crack your quartz sleeve and then cause all kinds of problems in your tank.  If you run it on the return side you can orient the UV so that it retains some water instead of going completely dry whereas on the drain side of a bean animal I can’t imagine anything good coming from orienting it to hold water in the UV as the back pressure issues would probably be more difficult to account for in tuning.

[fellterrier]

Another thought: Run all your main tank drain flow back thru the UV. No head pressure loss that way.

I think that this is the best option and plan to plumb that way


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[fellterrier]

Works flawlessly


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