UV Sterilization in-sump set-up question.

[Tankster]

Thanks for reading:

I have a 240 gallon tank running a 75 gallon 3 chamber sump using poret foam for dividers. Total volume is around 300 gallons as the sump runs at about 3/4 water level.

I have been reading up on UV and am more confused about UV now than when I started and am struggling to figure out the best, and most economical solution for my set-up.

I am running the Waveline DC 10,000 which runs at 2,853 gph at max flow. I am dialed back to about 1,000 gph.

I want to run UV in my return pump chamber, which is where I also run my heaters.

Now to my question:
In reading up on this I have seen where people will use an aux pump to run water at around 250 gph through a encapsulated UV and back into the return chamber. The intended logic behind that is maximizing water exposure to the UV light. If your running a main return pump at 1,000 gph and your UV treatment runs at 250 gph you are not treating the entire column before return.
Unless you want to drop around $800 there is not a contained system that will treat that volume of water throughput.

Why can't I just treat the entire chamber with a couple of these? Is there a downside to 2 open UV tubes in my return chamber? (not actual product I am considering - example only)

 

[Wobblebonk]

Well the dwell time (of the water and by extension microbes)/ flow rate around the UV determines what it can kill or not... you don't need to treat the entire column before return but the uv that is there needs a proper exposure time to the things it's trying to kill in order to do what it's supposed to. I don't think just throwing 4 250gph units in front of a 1000gph pump will work how you want but I am not certain of that...

It doesn't need to kill everything all of the time... especially if you're going to run it 24/7.

 

[Tankster]

Well the dwell time (of the water and by extension microbes)/ flow rate around the UV determines what it can kill or not... you don't need to treat the entire column before return but the uv that is there needs a proper exposure time to the things it's trying to kill in order to do what it's supposed to. I don't think just throwing 4 250gph units in front of a 1000gph pump will work how you want but I am not certain of that...

It doesn't need to kill everything all of the time... especially if you're going to run it 24/7.

Thanks for the input. I am going to have a UV PhD before this is over

 

[JLW]

Probably because you don't want to go blind when you open the cabinet.
If the UV is actually working, the leaking light is extremely damaging to everything it contacts, including your eyeballs. That's why we use enclosed units. You also don't want to kill stuff that's growing on media, your good bacteria. You just want to kill free floating stuff.

When sizing the pump to the UV, you want to have a flow rate through it so that the "dwell time" is sufficient to kill whatever you want. UV doesn't kill instantly, but over a longer period of exposure, depending on how strong the UV is (i.e., a 50-watt might take 3-4 seconds to kill stuff, whereas a 250-watt might take 1 second). This will also depend on what you're trying to kill -- the more complicated the organism, the longer it takes.

You want stuff passing through at a flow rate that is slow enough to kill your target, be it bacteria or algae or pathogens, but you want to have a flow rate that is high enough that enough volume passes through it to be meaningful. You wouldn't expect a 10-GPH pump to be able to make a real dent on a 500-G aquarium, for instance. As a rule, you should pass the entire tank's volume through the UV once every 30 mins to 2 hours, depending on what you're trying to kill exactly. (Bacteria < algae < pathogens ).

I would run an aux pump through the UV, and back into the sump (ideally so that it passes through poret). This will make service easier, too. It does not matter that the whole return is not going through it -- your whole tank isn't going through it anyhow, so stuff continues to reproduce. What does matter is that its killing off a good portion of stuff that flows through every so often. UVs aren't intended to kill everything, they're intended to lower populations down to manageable levels.

Even if you look at something like, say, ich, a good portion of the ich is living on the fish, in your gravel, whatever, and will never pass through the UV. You're trying to reduce the free floating stage enough that the fish's immune system can handle it.

 

[Gary Stonebraker Jr]

When using UV lights you have to contain the light, that is the cast of the light. Anything it touches or the rays hit has to be UV protected or rated. If the items that are in contact with the light are not UV protected it could cause what they call a burn. If I were to use a UV light it would have to been self contained unit, and the amount of water flow through it really doesn't matter as long as the amount it does is properly affected.

 

[Tankster]

Do you suppose I could paint the glass black in the last chamber and cover with opaque top?

3 11 watt bulbs on 3 sides of the glass (end and 2 sides) seems like it would effectively treat that space which is 18x11x12.

The UV will not run 24/7 but be on a timer to run 9 to 10 hours overnight.

 

[littlen]

So you're essentially making an enclosed chamber for it out of a compartment in your sump? And not running it all the time?

Why not just buy an already enclosed unit and it can run all the time w/o the need to modify the sump. As mentioned, having it as a 'side stream' in your sump makes maintenance simple. I can understand the desire to treat all of the supply water as it leaves the sump, but that just isn't necessary. (Unless you plan on having a knowingly dirty or infected system and you desire to use UV to rid yourself of the associated concerns). Typically UV is used as a side stream so that you can have a slower flow which means more exposure to the UV. Trying to move all the supply water through it too quickly isn't going to be effective.

Maybe you just really like those units. That's ok. Not my eyeballs! Good luck either way.

 

[Tankster]

Why not just buy an already enclosed unit and it can run all the time w/o the need to modify the sump.

Cost is my motivating factor. Modifying the sump is really easy - 10 minutes and some black paint. The open submersible UV lamps are dirt cheap compared to a pre-packaged enclosed system (for a tank my size). Cost difference is $80ish for DIY and $600 + for a system that would work on my tank. A smaller enclosed systems running on my tank would not do much of anything.

 

[JLW]

If you have it running a third of the time... its no better than pushing a third of your water through it all of the time....
And you've got some half cocked cobbled DIY system that will probably blind you some day.

 

[Tankster]

From what I’ve read, you’re not supposed to run these systems 24/7.
I see your not a fan of DIY.

 

[Wobblebonk]

https://smile.amazon.com/Jebao-Clarifier-Sterilizer-Aquarium-Fountain/dp/B0034V9P6W/
https://smile.amazon.com/Oxyful-Non...terilizer-Clarifier/dp/B01HSS87PG/?pldnSite=1
+ some tubing and a pump is well short of 600~
i dunno if i trust this 4400 gph nonsense bit but jebao pumps have been good to me...
Aquatop is like 120 https://www.kensfish.com/aquarium-supplies/uv-sterilizers/aquatop-inline-uv-sterilizer-36-watt.html

Diy is fine but I personally wouldn't do that to my sump and the uv will mess up the plastic on your pump probably like that...

 

[littlen]

I understand your concerns with cost, naturally. And I am a huge fan of DIY. But I second this:

If you have it running a third of the time... its no better than pushing a third of your water through it all of the time....

I think either way you go, you'll have improved WQ for your system. So when you look at it from that angle, it is a win-win. They say to never look at the sun, but I think just about everyone has.

 

[Tankster]

https://smile.amazon.com/Jebao-Clarifier-Sterilizer-Aquarium-Fountain/dp/B0034V9P6W/
https://smile.amazon.com/Oxyful-Non...terilizer-Clarifier/dp/B01HSS87PG/?pldnSite=1
+ some tubing and a pump is well short of 600~
i dunno if i trust this 4400 gph nonsense bit but jebao pumps have been good to me...
Aquatop is like 120 https://www.kensfish.com/aquarium-supplies/uv-sterilizers/aquatop-inline-uv-sterilizer-36-watt.html

Diy is fine but I personally wouldn't do that to my sump and the uv will mess up the plastic on your pump probably like that...

THANK YOU!!!! I have been causually looking for a few weeks and everything I've seen was $600 to $800+. I really appreciate you digging this up for me. I am going to Kens website right now to buy

 

[Tankster]

**UPDATE**

I took everyone's advice and went with a Lifeguard Pro-Max 90 watt High Output Amalgam UV Sterilizer. The unit is rated for a 650 gallon tank and 4,600 GPH which is a bit of overkill for my 300 gallons and 1,800 gallons per hour but why not, right? The unit installs right into your return line between the sump and tank.
They were having an amazing deal on these and I picked mine up for just at $400.00 The price drops significantly if you go down to the 300 gallon rated system.

Thanks everyone for saving me from myself

Lamp Watts 90 / Lamp Current 1.2A / UV Output Micro watts .27 / UVC pW-cm Radiation 270 / UV-C OutputWatts 28 / Bulb life 9,000 hours


3" main chamber 33" long


Ballast with countdown timer and failure alarm


Inline installation