# 13 watt UV sterilizer not working?



## WIfishguy373 (May 11, 2010)

Hey folks I have a 4 week old 75 gallon tank.
It is moderately planted.
Substrate-SMS with a bottom layer of sphagnum peat moss
Lighting- 216watts of t-5ho 6700K bulbs...four bulbs total...lights run for 8.5 hours
150 watt heater
13 watt uv sterilizer...220gph runs 24/7
1 fluval U-4

It has a lot of fish in it and they always eat all the food I feed them very quickly.

I have a diy co2 system...3L bottole with sugar and yeast...tube goes into uv sterilizer's venturi intake so it shops up the co2 pretty well...I know I am not over dosing because the fish are not gasping at the surface.

My question is that I have this greyish black hair algae growing covering my plants. 2 chinese algae eaters are not eating it.

I think it is Audouinella. The algaeFinder on this site is vague about this type and the pictures dont work for me.

I need to get rid of this...why isnt my sterilizer working? Or is it?

I dose with liquid Plant Pro and use api root tabs

I can post pictures if wanted and also any advice would be great!

Thanks!


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## HeyPK (Jan 23, 2004)

You can't expect your UV sterilizer to kill attached hair algae that, being attached, is never going to be exposed to the UV. The UV sterilizer is good for getting rid of planktonic algae in the water.


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## DVS (Nov 20, 2005)

I would expect that your algae is probably due to low CO2/high light (and possibly other nutrient deficiencies). DIY CO2 in a 75 is going to be problematic.

I don't have any experience with UVs but in addition to what PK already pointed out, I know UV lights need a set exposure time to work. Is the 220 gph what is suggested for the light? Seems kind of high to me.


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## Seattle_Aquarist (Mar 7, 2008)

Hi WIfishguy373,

First of all, welcome to APC! I see you are relatively new and I don't believe we have welcomed you yet!

I agree with both the previous posts UV will not treat attached algae; and the 13 watt UV I am familiar with is rated for 145 gallon per hour flow maximum. If the flow is greater than that, the water does not stay in contact with the UV light long enough.

That is an awful lot of light on a tank that size. If you don't have a consistent and sufficient supply of CO2 algae may become an ongoing problem. Here is where I go to identify algae issues.

Keep us posted on how things progress!


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## Elohim_Meth (Nov 4, 2007)

Probably it's not hair algae but rather BBA, black beard algae.


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## freshyleif (Jan 9, 2008)

Like the others before I think that with that much light you need more CO2. I have the same set up and the algae did not respond to anything until the CO2 was raised until the fish gasped and backed off a little. If you want a fish that will eat that algae in my experience black mollie's are the only fish I have seen grazing on it as long as they are not getting to much regular fish food.One other rout you could try is if you don't want to raise the CO2 you could turn off half your light and reduce the fertalization also to balance with the CO2 you have. Last little note would be to ask about the amount of mulm build up.Is there a lot or can you clean the substrate when doing WC?


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## WIfishguy373 (May 11, 2010)

freshyleif said:


> Like the others before I think that with that much light you need more CO2. I have the same set up and the algae did not respond to anything until the CO2 was raised until the fish gasped and backed off a little. If you want a fish that will eat that algae in my experience black mollie's are the only fish I have seen grazing on it as long as they are not getting to much regular fish food.One other rout you could try is if you don't want to raise the CO2 you could turn off half your light and reduce the fertalization also to balance with the CO2 you have. Last little note would be to ask about the amount of mulm build up.Is there a lot or can you clean the substrate when doing WC?


There is some mulm...what ever i can clean out I do when I do the weekly wc


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