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Old 10-16-2010, 05:36 AM
GpsFrontier GpsFrontier is offline
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Location: Lake Havasu AZ.
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Originally Posted by watercatwn6535nd View Post
Just reading your post made me think of a extra UV light i took out of a old hut tub. I have never researched it but that may be a great way to keep algea down and stop small emmiters from clogging? what do you know about it.
UV light is a form of low radiation (below X rays), it's safe for humans (that's what they use in tanning beds), but deadly to micro-organisms. Basically once the micro-organisms are subjected to the light, they die almost instantly. Not exactly instantly though, and some organisms take just a little longer to kill than others, but die within a few seconds rather than minutes (depending on light intensity). Once the water/nutrients are not under the light anymore, micro-organisms will be able to grow again. That's why UV light treatments generally recirculate the water continually under the light, killing any new organisms that may grow. Basically it would be able to keep the water/nutrient solution free of the algae and any organisms with enough UV light. It wont be able to keep the emitters themselves from algae growing on them because they are not under the light. But it can help keep them from clogging, simply from algae buildup in the reservoir getting in the lines then clogging the emitters.

There are a few things to consider when using UV light treatment, one is that (like any light) it will only penetrate the water so far before it's diminished to much, second is what commercial UV light treatment setups call a flow rate. That's basically how long the light is subjected to the water/nutrients as it flows through a tube under the light (compared to how much water flows past). Also the light won't be able to penetrate as well if the water is cloudy or murky.

I have not built one yet but would be fairly simple, and I see two ways of doing it. One, a UV light or series of UV lights at the top of a tube or channel (like a rain gutter, or PVC tube) that kills the organisms as it flows through (to or from the reservoir) with the water depth about an inch. The other is a UV light in the reservoir itself, like attached to the lid or shining through a hole in the lid. Either way just make sure the light is protected from moisture or it may short out. Also make sure it's ventilated so you don't have heat build up, shouldn't be much the light tubes are basically the same as a florescent light tube. The light wont be able to penetrate all the way down to the bottom of the reservoir, but as the water is pumped through the hydroponic system it should circulate the water enough to keep it free of any organisms because the whole reservoir is it's continuously subjected to the light.

Here's a couple of links that I still had bookmarked on UV light treatment
Water treatment options
Ultraviolet Disinfection Technology
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