What does UV sterilize other than algae and micro organism?

[blackBRUSHalgae]

ok I have always wanted to know this.

Other than algae and any other organism in the water column that would be sterilized by UV, what else?

How about trace elements, chelated Fe, lushgro NO3/K/PO4, etc.?

I really want to know how UV would affect my fert dosing.

[Aeon]

Basically UV has 3 spectrums. UVA, UVB and UVC. The last 2 are the most harmful. Can cause cancer. UV radiation kills all sorts of living organisms, e.g. virus, bacteria, algae, protozoan, etc by damaging their DNA.

I have seen some website mentioning UV "oxidizes" trace elements. But oxidization is a process when a substance reacts with oxygen in the air/water, e.g. rust, tarnish. UV does not emit oxygen.

Something to note is that Zinc oxide (a sunblock ingredient) absorbs UVA and UVB.

[stephen chung]

Aeon,

What should we use for algae control? UVA UVB or UVC?

[Aeon]

Ultraviolet light is electromagnetic radiation with wavelengths shorter than visible light. UV can be separated into various ranges, with short range UV (UVC) considered “germicidal UV.” At certain wavelengths UV is mutagenic to bacteria, viruses and other micro-organisms. At a wavelength of 2,537 Angstroms (254 nm)[3] UV will break the molecular bonds within micro-organismal DNA, producing thymine dimers in their DNA thereby destroying them, rendering them harmless or prohibiting growth and reproduction. It is a process similar to the UV effect of higher wavelengths (UVB) on humans, such as sunburn or sun glare. Micro-organisms have less protection from UV and cannot survive prolonged exposure to it.

[Shaihulud]

I have seen some website mentioning UV "oxidizes" trace elements. But oxidization is a process when a substance reacts with oxygen in the air/water, e.g. rust, tarnish. UV does not emit oxygen.

That i think comes from the fact that UV light does cause free radicals to form in a living organism, the damge the radicals form has been popularly been publicised as oxidation damage, thus the anti-oxidant health products that we see in the market. People automatically associates UV light as being an oxidation agent which it is not.

[Shadow]

some paper on uv photooxidation:

http://www.purdeyenvironment.com/uvpaper.htm

Just google "UV "oxidizes" trace elements" lots of info there

[Shaihulud]

However i look i can't find an article saying that UV light would oxidise metal groups which trace elements are composed of. Oxidation by photo radiation seems to be by creation of free radicals and organic in nature.

Chelation is actually trapping the iron inside an organic molecular ring in the form that the plant can readily use. (Plants readily absorbs certain oxides and not others) UV light might oxidise the organic molecule, but it would never affect the metal within. The metal would eventually oxidise naturally, but UV light should not increase the rate of oxidisation of metals, fertilizers etc.