# UV Light & Fertilizers



## NinjaPilot (Jul 31, 2016)

I have found that UV light breaks the chelating bond. So chelated iron, or other chelated fertilizers will be rendered useless in the aquarium. I'm still researching UV and it's action on fertilizers. I am sad because I really like using UV light to clean my tanks of algae and bacteria in the water column. But I may have to use them only when necessary, instead of keeping them running daily. I guess my Vortex Diatom filter is still the best way to clean parasites, but I wish it did as good a job on bacteria. From what I've read, bacteria is slightly smaller than 1 micron in width, but longer than 1 micron in length, so the diatom filter really doesn't clean bacteria very well since it cleans down to 1 micron only. :sad:
http://fins.actwin.com/aquatic-plants/month.200508/msg00317.html


----------



## Harry Muscle (Oct 17, 2007)

I wonder if there's any research on the strength/dosage of UV light required to cause the chemical bonds to break.

Thanks,
Harry


----------



## NinjaPilot (Jul 31, 2016)

Harry Muscle said:


> I wonder if there's any research on the strength/dosage of UV light required to cause the chemical bonds to break.
> 
> Thanks,
> Harry


I'm guessing there would not be much of a difference regarding breaking the bonds. I have Green Killing Machine UV's and they move water very slowly, and are at 9 watts. When I add fully chelated iron (FeEDDHA), which tints the water red, the red tint is gone within about 24 hours, in a 55g with the UV. Whereas the same amount of iron added without UV remains tinted red for at least a week. I noticed this and did the research to find out why...and learned not to fertilize chelated iron while the UV is on the tank. It would be nice if there is such a thing as UV that doesn't break the bonds. I'll look around and see what I can find. I'm not sure what other fertilizers are chelated for aquarium plants. So far, the only chelated dry ferts I use is the iron. It is probably a bad thing to break these bonds because the chelating salts could create a toxic mixture in the tank. I know that happens with EDTA iron, which is one reason I stopped using it, and switched to the FeEDDHA. My plants have really strengthened with it's use.


----------

