# Cant clean up green water



## Jamie McGrath (25 Nov 2015)

Hello there, im hoping some one can help me. About a month ago my tank was very overgrown, i stripped out loads of plants, stired up the sand and replaced all of the media in my filter. After a week the water became cloudy so I did the usual large water change but this did not clear the water. The next couple of days I did some smaller water changes but again the water was still murky, a bit like some milk had been poured in the tank. I got desperate and did another large water change and washed the filter media with boiling water. The tank look clear but after 2 days the water went greenish. I got a water clearing chemical from the shop and added it to my aquarium and continued to to small water changes every day. The water is now so green I cannot see the back wall. I have been searching the internet for some help and I found some advise on the issue, the solution says I should leave all the lights off and cover the tank with a towel so the algae dosnt get any light. I have no covered the tank with bin bags, switched the lights off and will leave it until the weekend. Is this a good idea?


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## tim (25 Nov 2015)

Yes a blackout may help, I would say the issue arose from your rearrangement of the tank which caused an ammonia spike, then unfortunately you boiled your filter media which would have killed any bacteria so essentially you are in new setup territory, personally I would carry out plenty of 50% water changes until the tank settles again and add in some fast growing plants for now to soak up any ammonia/nitrogen from the recycling of the tank, could take a few weeks, do you have livestock in the tank ?


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## Jamie McGrath (25 Nov 2015)

yes I have got livestock in my tank. I have added some new plants as well, I did think that would be helpfull. The man in the shop suggested I didnt do any more large waer changes, he said I would just be diluting the algae and the tank needs some time to stabilise.


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## foxfish (25 Nov 2015)

Considering you don't presently have any active  biological filtration but, do have livestock, I would most definitely recommend lots of water changes!


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## Jamie McGrath (25 Nov 2015)

What % water changes would you think?


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## JohnC (25 Nov 2015)

beyond the water changes mentioned above you could also try a small internal UV filter for the duration of the outbreak. I always keep one handy in the rare circumstance that I get a green water algae issue and don't want to black out the tank.

Best Regards,
John


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## dan4x4 (25 Nov 2015)

Only had this once but black out worked for me, covered mine with a towel, 3 days it was fine. I didn't dose any liquid ferts during this time. I diddnt feed the fish either. Its annoying not being able to look at it. I think I had caused it because of disturbing the filter, but Im not sure.


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## Martin in Holland (26 Nov 2015)

You probably eradicated all bio of your filter and this has to get back to it's old capacity, your tank needs to be cycled again, large water changes would be in order (atleast 3 times per week 50%, but more is better), keep an eye on you Nitrite levels, some Carbon or Purigen will help with your cloudy water.


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## ceg4048 (26 Nov 2015)

Jamie McGrath said:


> The water is now so green I cannot see the back wall.


Green Water Algae (GWA) can be cleared up in a few days with the use of an UV. Blackouts may not help.

Annihilating your filter bacteria by pouring boiling water over them is not generally a good idea. I think Joan of Arc  was executed in this way. Very painful.

Cheers,


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## Martin in Holland (26 Nov 2015)

Never used an UV, but if Clive is saying it would work I am sure it will.


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## viktorlantos (26 Nov 2015)

Also not sure about the natural or ambient light if that changed, but may need to be decreased. +1 on uv with the correct flow! Ran it for 2-3 days then a water change would do the work.


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## foxfish (26 Nov 2015)

How much will a UV light cost and will it be of any use once the green water has cleared?


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## viktorlantos (26 Nov 2015)

foxfish said:


> How much will a UV light cost and will it be of any use once the green water has cleared?



Not much use after that. But some ran it for 24 hrs like we do in cases. 

Would be useful if shops could let it rent for cure. We dif this in the past in our country but we stopped as the uv tube damaged with the heavy logistic. Still it was a good idea then.


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## ian_m (26 Nov 2015)

Something like this in your external filter outlet will do it.
http://www.aquacadabra.com/tmc-vecton-v2-nano.html

Must be sized according to filter flow as if flow is too fast the UV wont work effectively.

Also must be not used with micro fertilisers as it will degrade the chelated elements.


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## zozo (26 Nov 2015)

Here you have a video of UV in action.. 


Now you learned the hard way..  Always perform maintenance in intervals. 1 day substrate vacuuming, glass cleaning and water change. Wait 1 or 2 days for the filter cleaning. Never clean with hot water or chlorinated water. It's tempting to do all in one day and use aquarium water to clean the filter. But better to store the water in a bucket if filter cleaning is up.. .

It very common to get bacterial bloom if all is done the same day, happens to me too.. Not that drastic but still see it happen..

Good luck.. 

You can keep it running, it seems to clear out more than just green algae blooms, but not realy necessary to keep running it. But ask around, they sometimes are also for rent as victor says.. Best chances pond shops do, because they are more used by pond keepers than aquarium keepers..


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## dw1305 (26 Nov 2015)

Hi all, 





tim said:


> then unfortunately you boiled your filter media which would have killed any bacteria so essentially you are in new setup territory





foxfish said:


> Considering you don't presently have any active biological filtration but, do have livestock, I would most definitely recommend lots of water changes!


Yes up the water changes and I'd add some more plants, as soon as possible. A floater would be best, as it  would have access to full light and atmospheric CO2.

I definitely wouldn't add UV, or have a black-out, at the moment, and not until your biological filtration is fully functioning.  I'd also add an air pump or have a lot more surface ripple. You could filter it out with a fine filter material, but you would need to keep cleaning this ensure that flow isn't compromised. 

The "green water" is a symptom of the high nutrient levels in the tank. Any plants, even undesirable ones like _Chlorella_, are performing a useful role in removing NH4+ from the water column. If you kill the green water algae off, with black-out or UV, you run the very real risk of the increasing ammonia levels over-whelming the filtration capacity of the microbial community in your filter.

A black-out is the double whammy of no oxygen production from photosynthesis, combined with the extra ammonia production from the dead and decomposing algae.

cheers Darrel


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