# Green water



## spill50 (5 Nov 2011)

Hi all,

Since adding pressurised co2 to my tank (was previously using dosing easy carbo only) I'm getting great plant growth but over the past week I've been getting green water. I've upped the amount of water changes but this only reduces it, doesn't get rid of it.

Any suggestion on what I need to do to fix it? Would a uv steriliser sort it. If so would this be suitable:

http://www.ebay.co.uk/itm/11W-POND-...Features_UK&hash=item2c5f5359f3#ht_1316wt_989

Thanks, Richard


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## Matt Warner (5 Nov 2011)

Hi, A UV steriliser will get rid of it but so will better filtration. Have you got anything rotting in the tank? How long do you have the lights on for? How many fish do you have?


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## spill50 (5 Nov 2011)

It's a 120L tank. I have an aquamanta efx 300 filter which is rated at 1100lph. I get pretty decent flow around the tank with no dead spots I'm aware of. Nothing decaying that I'm aware of. I've got the odd bit of plant matter but I try to remove that quickly. All fish are accounted for, stocking level is pretty light as I'm planning on a complete rescape after christmas so it's a bit of a random selection in there at the moment.

2 pearl gourami
3 long finned danios
7 neon tetras
3 peppered corydoras
1 small plec (not sure of the species, I should really look it up)
And a few Assassin snails

The only thing that's changed recently is switching to pressurised co2 and switching the ferts to APF all in one plant nutrition.


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## Alastair (5 Nov 2011)

It's usually caused by ammonia. Try a 4 day black out, with a big water change straight after should get rid. Also as states the uv will help too


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## Matt Warner (5 Nov 2011)

Yes a blackout will definately help with it. Does the tank get a lot of natural light through a window or anything like that? Have you added any bogwood recently which may have discoloured the water? Maybe adding a fine filter floss in your filter might help too.


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## spill50 (5 Nov 2011)

Hmmm, just tested for ammonia and nitrite, both are zero. I may increase my water changes again to every day for the week to see if that helps. Failing that do the blackout.

Would the uv filter I linked in the first post be suitable, or would I need a higher wattage one? I take it that it will just fit inline with the filter inlet/outlet?


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## Alastair (5 Nov 2011)

The ammonia spike may have already happened hence the green water, and if you've since done water changes then it won't show. I'd just black it out first to save the expense of buying the uv


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## spill50 (5 Nov 2011)

thanks guys, I'll try the black out see what happens. I seem to remember a post on how to do blackouts I'll have a look see if I can find it.



			
				Matty1983 said:
			
		

> Yes a blackout will definately help with it. Does the tank get a lot of natural light through a window or anything like that? Have you added any bogwood recently which may have discoloured the water? Maybe adding a fine filter floss in your filter might help too.



No direct sunlight, it shines in on the opposite wall to the tank and only in summer, the sun is too low now. No new bog wood, the large piece that's in there has been there nearly 2 years. Already got the filter floss in I always have some in.

Do you think adding purigen to the filter would help?


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## ceg4048 (6 Nov 2011)

GWA is most efficiently handled by running a UV for 3 or 4 days.

Cheers,


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## spill50 (6 Nov 2011)

Thanks ceg,

Do you think the one I linked in the first post would be suitable for my size tank (120L)?


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## ceg4048 (6 Nov 2011)

Yeah, that'll work. 40 quid though? Would be cheap at half the price....

Cheers,


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## spill50 (6 Nov 2011)

Thanks, I'll see if I can find any cheaper.


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## ceg4048 (6 Nov 2011)

You might want to consider getting second hand.

Cheers,


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## Matt Warner (6 Nov 2011)

Why not post a wanted on the for sale and wanted section. I'm sure someone will have what you want.


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## spill50 (6 Nov 2011)

Yeah will do, just been checking on eBay, nothing less than £30.


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## spill50 (13 Nov 2011)

Just an update on the GWA situation. I ended up going the UV route got a 9W one off ebay, couldnt find a second hand one. I did a large water change when I installed it and 3 days later I don't think my water has been this clear since I first setup my tank  I think I'll leave it on for another day then see what happens when I turn it off. Anyway thanks again for all your advice guys, it's such a good feeling to get the tank back to normal again after an algae outbreak.

Richard


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