Uv Sterilizer And Fertilizers

[SuperColey1]

I have read in another thread about UV Sterilizers that they may break down some parts of the fertilizer that I am using in my planted tank.

Does anyone have any knowledge or links about this.

Should I turn the UV off and use it more sparingly (I currently just leave it turned on 24/7 to kill parasites etc.)

This has started me worrying that I am wasting my fertiliser money by using the UV all day, although in the 6 days the plants have been in there there has been a lot of growth so I must be doing something right.

I am using Aquatic Plantations' own brand fertilizer half daily dosage because I am overstocked and therefore will already have some nutrients from the fish waste.

Any opinions on this most welcome.

 

[JamesC]

This topic seems to come up quite often. The answer I think is that nobody really knows. I and many others run UV 24/7 with no problems. Others complain they have problems with iron deficiency. What UV seems to do is break the bond with the iron chelator in the chelated traces mix. Does this really matter you may ask? The iron is still there but in a different state. To what I can gather plants seem to be able to use both ferrous and ferric iron so I can't see a real problem. Light will also break the chelator bond but not as quick as a UV steriliser. Also it depends on what chelator is used.

If you dose your traces every day or other day then you shouldn't have a problem. But if you're worried about it then just run it for 24 hours after a water change or tank cleanup.

James

 

[MoreCoffee]

As James says, questions on the impact of UV on plant nutrition have come up a few times in the past and as my AquaEl 500 filter has a 9W internal UV sterilise in it,
I decided to look into it again quite recently.

Whilst I'm certainly no expert on the subject I have seen lots of people who do run UV and also seen comments on the subject from Tom Barr (quoted below from his own site) that suggests there is no real proof that UV causes any issues.

"........The other issue that the UV's wavelength is different than the Sun's and generally more narrow. Many chemical bonds and complexs are specific to a particular wavelength for degradation.
Given that people have only actually used field data from natural systems to justify the UV sterilizer claims that it breaks down iron complexes, RATHER than any real data from an aquarium, this seems speculative at best and at worst simply wrong/insignificant.
I think the burden should be on those wanting to make this claim to show that it is or is not significant.
The observations with using UV's and dosing traces sure don't seem to support their contention.

I figure if I can trust his judgement enough to add chemicals to my tank (EI), I can trust him on this one ...... until somebody proves otherwise !

 

[raptorrex]

perhaps a pond uv unit may be of more use, they work in a slightly different way to an aquarium unit. and most ponds are planted, whether by design or just through nature.