# UV Steriliser... worth it?



## Chris25 (20 Sep 2017)

Hi all,

I'm setting up my 5x2x2ft tank and have all the main equipment I need.
I'm just wondering if it'll be worth adding a UV Steriliser to the system?
I'm thinking of over doing it with https://www.allpondsolutions.co.uk/aquarium/filters/uv-sterilisers/72w/.
I'm thinking about running the pump fairly high flow during the day (4-5000 l/h) and then slowing this down at night for the fish to rest (if this is possible...). 

I'm thinking during this slow night period I could have the UV come on as it'll have more contact time with the bulb and just help keep any algae at bay... If this isn't possible then just have the light on for a period of time or all day.

Any thoughts?

Thanks,
Chris


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## foxfish (20 Sep 2017)

UV light only helps with free floating algae (green water) so very few folk use them on planted tanks.


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## Lgtuk (20 Sep 2017)

I have an APS uv system built into my filter. It makes no difference to hair algae but I have not suffered from anything else but that might not be down to the uv.


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## three-fingers (20 Sep 2017)

Built-in UV systems are very inefficient and are only useful in preventing green water - something that shouldn't be a constant issue in a planted tank anyway, so are only remotely useful for the first few weeks, after which the bulbs just wastes electricity with no measurable benefits for the aquarium.

Large stand-alone UV units with a specific low flow rate though them (you want a high watt bulb with a low flow rate) can have benefits for water conditions for the fish, and improve water clarify a little in some tanks...but will also destroy the chelators in the fertilisers we use, so you will often need to add more chelated iron if you use a UV unit.

Generally, for planted tanks, UV units just aren't worth the running costs. They don't solve any problems and sometimes create a new one (iron deficiency). I have a UV unit on one of my small planted tanks that I got pretty much just to experiment with, a 7w one from All Pond Solutions on a tank around 80l, with water running through it at less than 150lph.  It's usually turned off because I fertilise the tank almost daily and don't want to waste the fertilisers I put in (I forget to switch it back on), but I turn it on for at least a day or two after doing a  water change, just so I can appreciate water that I know its at optimal clarity for viewing and quality for the fish.

If you are interested in using one, make sure you understand all the reasons why, this page is a very good (but long) read: http://www.americanaquariumproducts.com/AquariumUVSterilization.html

Just remember the part about UV destroying the fertilisers we put in. Personally, for water clarity, I would recommend Seachem Purigen over a UV unit.


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## Authur11 (30 Oct 2021)

I am facing cloudy water and algae blooms in my tank. But luckily, Fluval in Line UVC Clariifier solved my problem. I was astounded because the water in the tank had become crystal clear after only one day of use, and the algae that had been giving me headaches had been cleaned up.


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