UV Light Question

[Goldfish345]

Hi, I recently bought a UVC light on amazon to combat green water issues in my 55g. To clarify it is not a UV internal canister or anything like that; it is just a UVC blub that plugs into an outlet. I see conflicting information on this, but will it ruin my cycle. I placed it directly in my customized HOB. My HOB goes old (cycled) gravel > bio rings > filter floss > filter cartridge with carbon. I placed the UVC light directly under the filter floss, on top of the bio media. So will it ruin my cycle or not?

 

[blackberry75]

Personally, I'd put it where it's the last thing the water passes on it's way out or the first thing before the biomedia. But I'm not an expert by any stretch. Hopefully this will bump your post so someone smarter than me will chime in

 

[Aiken Drum]

UV will kill off any beneficial bacteria in the water column. So if you are cycling the tank it could kill off bacteria and prevent your cycle from establishing.

So for example if you are dosing bottled bacteria like tetra safestart UV will kill off the bacteria present in the solution. Or if you are relying on establishing your cycle naturally, bacteria gets into your system from the atmosphere. Again UV will kill off the bacteria. It takes a while for it to start growing on filter media.

For this reason i wouldnt use UV while cycling a tank.

If your cycle is established, as long as the UV isnt casting light on your filter media it wont effect your cycle.

I prefer a sealed UV light to the type i think you have. I have one of these that i can drop into a tank when needed. Works very well.

https://www.amazon.co.uk/Fish-Inter...-b1c9-8d0f72e53e4c&ref_=pd_gwm_ci_mcx_mr_hp_m

The type you have is more commonly used in a sump in a chamber seperate from filter media, but i have seen them put in HoB filters. You would have to make sure its seperated from filter media which i imagine is difficult to do in a HoB.

 

[Goldfish345]

Ok thanks. I found an old internal canister that I will use just for the uv light. That way it’s not effecting the cycle.