# Thread: UV sterilization?

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Originally Posted by CCWKen
1200 gallon pond? Is that a typo or is that pond six feet deep?
That's about 160 cubic feet of water! I have a 1000 gallon rain-water capture tank that looks larger.
Ok Ken. No joke there could be multiple errors going on with my numbers

I should have stayed in school. I cant spell and I cant preform even simple math.

Ok, when I was building the pond I wanted to know how much it was gonna weigh (dont ask). So I did what I could to figure it out. Here is my math. Yes, more like 1100 gallons NOT 1200, I was going off of bad memory

Lemme know? Is my math no bueno? Thanks, JR

The "/" marks are not division symbols.

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It should be 25.500 cubic in inches not 255.000

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Originally Posted by Jaakko Fagerlund
It should be 25.500 cubic in inches not 255.000
Hmm? I dont understand.... Did I get the wrong number for the cubic inches? Thanks, JR

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Originally Posted by Mcgyver
I tried a small aquarium UV light for my ongoing central coolant project. Plastic peice of crap, useless.
The problems you had is not with the light but the coolant. It is fluorescent, meaning the UV light was being converted to visible light and the lamp could not do it's job.

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Originally Posted by Mcgyver
I tried a small aquarium UV light for my ongoing central coolant project. Plastic peice of crap, useless.

The next phase will be to acquire a little more beefy unit, something like would used on a residential drinking water supply.

The coolant I am currently using, Rustlik 5050 is opaque so the UV light loses a lot of its effectiveness. Still, I think brute force, cubic inches, should work....with a powerful enough light and fairly high volume circulation of a small tank I'm hoping the bugs get zapped.

proper management of the coolant needs filtration of returning coolant, air bubbler, oil skimmer and then there are other niceties; having it on casters with a drain underneath, one centralized pump, hinged lid ....all which adds up the idea of one central tank doing all of this

Coolant I used before that was translucent; Tri-Cool synthetic. It would work far better with the UV light but it is awful stuff, leave a sort of stickiness all over the machines and anywhere that it sprays that will only clean with water. I've also had a bad experience with how rapidly it goes rancid. Here's two pics, one Dec 22nd and one Feb 13, not even two months. The straw that broke the camel's back. This is in a brand new tank I made and used the cheesy UV light and bubbler. Their engineering dept/cust service/whatever dept didn't return my calls on why this happened

Did you do a write up on this with more details? As I am wanting to build one myself. I see some commercial ones recoup the coolant accidentally caught up with the oil off the skimmer.

Dave

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Originally Posted by JRouche
Hmm? I dont understand.... Did I get the wrong number for the cubic inches? Thanks, JR
Ah, sorry, my bad. I promise I won't do calculations when I'm sober

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Originally Posted by Davo J
Did you do a write up on this with more details? As I am wanting to build one myself. I see some commercial ones recoup the coolant accidentally caught up with the oil off the skimmer.

Dave
Dave my plan was always to do a write up, but its also an experiment....I need to get it more refined. I've also got a half done scheme for returning coolant without hoses across the floor. Everything overhead and blown back with air....need to get that singing as well. btw the saw blade is temporary, was a disk the right size...it sort of worked however I've purchase a proper disk which has the property of the oil liking to cling to it. Overall it's a work in progress although it is usable

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Originally Posted by macona
The problems you had is not with the light but the coolant. It is fluorescent, meaning the UV light was being converted to visible light and the lamp could not do it's job.
I don't understand that - its fluorescent?

the 'its crap' referred more its physique, it was just horribly made, press together plastics parts that would fall apart if you looked at it, very week pump etc. If never worked long enough to assess its effectiveness with bacteria.

Current think is something a little more heavy duty - the pond unit, or res water unit and using the beefy main pump to circulate.

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Mcgyver, the problem with "commercial" UV units, whether for aquariums, homes or whatever, is that they are constructed to a price point. This rarely coincides with optimum effectiveness.
First, you must use a "germicidal" lamp. I forget the wavelength of the output but I know that Phillips makes them, in the same approximate wattages as flourescent lamps. Match it to a quality ballast. The lamp must run in air to reach a reliable operating temperature. That means slipping it in a fairly close-fitting tube of UV-transparent material. Many commercial units use a pastic, but I forget what kind. It does not really matter; the BEST material is fused quartz. You can probably get it from Fisher Scientific and it wont be cheap, but it IS worth it.
The liquid to be treated must be clean; no lumps that create shadows where bacteria can hide from the radiation. It must also be reasonably transparent to UV radiation. Example:- for CLEAN water, maximum effective penetration is about one centimeter. ( Researchers have determined the effective UV energy dose in microwatts/cc and they then use a 1 cm depth water depth.)
On the basis of the 1 cm depth, and the annular volume between the quartz tube and its outer jacket, you instal a flow regulator such as a Dole valve to ensure that the energy/unit volume is reached.
You now have a WORKABLE UV sterilizer.
The jacket for the quartz tube can be ordinary pipe, PVC, aluminum, or stainless steel. The inlet and outlet are just close nipples. The ends of the jacket should be EASILY removeable but, since pressure is low, simple O-ring fittings will work.
Now for the BAD news. FIRST UV light reacts with all sorts of stuff. Most importantly, it oxidizes soluble iron, (which WILL be in your coolant,) to the insoluble form, which deposits on the quartz tube. This effectively blinds off the tube to UV radiation, even in a thin layer. Depending upon the rate at which it builds up it must be chemically removed. No big deal; a quick wash in either hydrochloric or oxalic acid cleans it right up. BUT, this is maintenance.
SECOND, this is NOT clean water; even after filtration, there is still the dispersed oil as well as that lovely flourescent colourant, (which I suspect is a dye of the same family as is used in antifreeze.) These both may absorb UV energy disproportionately, lowering the bactiricidal effectiveness.
If I were going to build a UV reactor for this application, I would cut the liquid DEPTH to about 5 mm, and DOUBLE the energy input, (by cutting the flow rate through reactor.) I think that I would design around a 20 watt germicidal lamp, which is about the same length as a 20 watt T8. For a lamp source, I would try a lighting specialist. Here in Ottawa, there is a firm, Buchannan Electric, and ALL they sell is light bulbs and ballasts. Otherwise, ask a biology laboratory where they buy theirs.
Any questions, PM me.

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## UV in-line sterilizers

For info, parts, etc., see: http://www.aquanetics.com/ or http://www.lifegardaquatics.com/prod...oduct.php?id=5
Had the Aquanetics 60w unit for many years. Other than changing the tubes every other year, no problems. Examined the Rainbow/Lifeguard filter UV unit first hand as well. Quality construction and the advantage of single ended UV bulbs and a test tube like quartz enclosures for the bulb.
Last edited by Rosco-P; 05-09-2012 at 12:14 PM.

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