# DIY UV Sterilizer



## evitagen22

So it looks like I have an algae bloom in my tank. I've been doing my research and looking at different ways to fix the problem, one of which is using the uv sterilizer. I've been looking around to see if I could find one for cheap and I noticed that I can buy the bulbs on ebay for about $10 while the entire sterilizer goes for $60 and up. 

So can I buy the bulb and make my own uv sterilizer? From what I can tell, the bulb socket looks like a common type (i.e. available at home depot). I think I have a 13 watt ballast hooked up to a socket that looks like it might work laying around at home. What I would do is mount it at the end of about a foot of 1.5" or 2" pvc, add some fittings for an input or output, and put it inline with my canister filter output. I would silicone around the base of the bulb to make the electronics waterproof.

It might not be as effective as the commercial versions, but it should work right? I could always buy a small (100 gph) pump specifically for the uv sterilizer for about $10-15 if the canister filter output is too fast.

Anyone see any problem with doing this?


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## NoSvOrAx

Yes you can you do it. But you better be careful. You don't want any of that UV leaking out. Its fairly nasty.


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## rs79

There's different types of UV and the bulbs at the hardware store, unless they say "germicidal lamp" are not what you want.

I just got a UV sterilizer for the house (well) water supply. It has a seriously weird bulb that's $100. The whole unis was about $300.

A diatom filter will get rid of green water, as will flourish excel.

I'll DIY almost anything, not homemade UV sterilizers. The radiation from the correct bulb is very very very nasty and home mad stuff where water has to come in contact with a fluorescent bulb is just aksing for trouble.

They're not expensive to buy if you want a small hobby grade one for a fishtank. Look on ebay or craigslist. The big ones that can do 30gal/minute like I have on my well pump are kinda overkill for fishtanks.


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## SKSuser

Here's a link to a specifically germicidal bulb for reference.

In addition to Richard's suggestion of trouble about creating something where there is about 1/64" of glass between water and voltage, there is another aspect of concern:

Most PVC isn't UV rated.

You could end up with a very brittle container which could burst or crack during use (possibly breaking the bulb and electrocuting you while you attempt to stop the geyser of water), or else one which develops pinholes and might leak for days or weeks before you noticed that your UV sterilizer had become a sieve.

PS.. The same company who I linked to has a two pin bulb that appears to be the same one that Drs Foster sells as a replacement for the Coralife Turbotwist. However, its only about $2 cheaper on the other site. In my opinion, that's not worth the possible savings to find out if its indeed the correct bulb.


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## hoppycalif

SKSuser said:


> Here's a link to a specifically germicidal bulb for reference.
> 
> In addition to Richard's suggestion of trouble about creating something where there is about 1/64" of glass between water and voltage, there is another aspect of concern:
> 
> Most PVC isn't UV rated.
> 
> You could end up with a very brittle container which could burst or crack during use (possibly breaking the bulb and electrocuting you while you attempt to stop the geyser of water), or else one which develops pinholes and might leak for days or weeks before you noticed that your UV sterilizer had become a sieve.
> 
> PS.. The same company who I linked to has a two pin bulb that appears to be the same one that Drs Foster sells as a replacement for the Coralife Turbotwist. However, its only about $2 cheaper on the other site. In my opinion, that's not worth the possible savings to find out if its indeed the correct bulb.


I think this is the best reason to leave the making of UV sterilizers to the professionals. Most plastics are sensitive to ultraviolet. Leave a piece of PVC pipe out in the sun, where just weak UV is hitting it, and it gets brittle in a couple of years. That same PVC exposed to intense germicidal UV could easily shatter in a matter of hours. Even ordinary glass won't withstand intense UV for very long. Quartz is used for that application, and even fingerprints on the quartz will cause cracking under intense UV.

Years ago I worked with a very high power UV "lightbulb", actually redesigning parts of it to make it last longer. I was astonished at how dangerous UV could be.


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## evitagen22

Well I think I'm going to try the blackout method for my algae bloom for now. I didn't realize that the uv light will damage normal pvc. Also, I couldn't figure out how to tell if its actually working or not given that you can't expose yourself to the light.

Thanks for the input everyone.


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## rs79

My US sterilizer is run by a ballast that beeps if the bulb isn't operating normally. The bulbs is plactes straight into a chamber that water runs through and has an unbelievable good seal at the base. 

The fact it's an immersible bulb probably counts for a lot of the $100 price.


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## happybob59

I saw this post from another forum that I'm a member of, since I work at Menards I can get supplies pretty easy...so tomorrow I will be trying this out when I get off work...

http://www.kokosgoldfish.invisionzone.com/forum/index.php?showtopic=10121


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## Squawkbert

"real" UV sterilizers do not have the bulb in contact w/ the water. They require a quartz sleeve to seal the water out while allowing the UV to pass through and do its thing. UV is quite hard on many plastics. Between a lack of ready-made (optically transparent at <200nm) quartz sleeves and plastic that's got enough Tinuvin or whatever mixed in, I'd leave it to the pros (but I'd step over a UV in favor of an ozonizer anyway).


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