# Green water



## knucklehead (Dec 27, 2013)

Im now experiencing green water. I didnt have this problem before. I just replaced the filter and also added new plants and fishes. i have read online info as on how to get rid of this and one of which is using excel. The problem with this is that I have vals. What othe options do I have? i've been doing large water changes for the past 4 days and also reduced the hours of lighting from 12 hrs(6-6) to 8hrs (4-4).

I've also recently added a DIY co2 yesterday if this info is relevant.

My tank is 30gal with 2-t5HO lighting. It contains several community fishes. i dont have water parameters as I've never ever used them since getting this tank.


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## Jacques (Jul 5, 2014)

Wow, you've made a lot of changes recently! Can you give a more detailed timeline for these changes? (new filter, new plants, new fishes, new lighting amount, new CO2, and when the tank was originally set up.) Also, did you seed the new filter with media from the old filter, to save the biobacteria?

We also need to know what species, sizes, and numbers of fishes you have, as well as species and numbers of plants. The idea is to determine what amount of nutrients end up in the water column, compared to what amount is absorbed by plants, and possibly filter media. Excess free nutrients feed algae, the cause of "green water". Algae also love light, so is the tank near a window? Keep in mind that new plants usually take some time to make a difference in absorbing nutrients, since their roots need to become re-established. When you have a good amount of established plants, there will be less dissolved nutrients to cause these algae blooms.

Good idea to reduce the light duration, as 12 hours is usually too much, in my experience.


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## knucklehead (Dec 27, 2013)

I' ve had the tank for about 9 months. Bought the whole setup with everything in it including plants and fish. I had 7 tetras, 1 cory, 1 pleco, 2 rasbora, 1 minnow with some java plants, vals,and crypts inn the tank before starting any changes.

I replaced the filter last week and bought 2 bundles of plants from the LFS to add to my exisiting plants and 3 tetras. Two days after got a couple of water sprites and hornwort plant cuttings from a member here. The otherday,I got 3 otto's and yesterday added the co2.


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## Jacques (Jul 5, 2014)

I forgot to ask the wattage of lighting, but I'm guessing those two T5's are 24 W each, in which case the amount of light is not too high. But how big is that pleco? They're poop machines, so if it's good-sized, I think that's your major source of excess nutrients. Otherwise, I think the fish load is okay. 

Your new plant species are good choices (fast-growing, so they'll suck up a lot of nutrients.) The only other thing that comes to mind just now, is that long (12 hour) light schedule was a little bit much, and with the summer sun possibly adding to the tank lighting, the algae began.

I would just keep up your regular water changes, and also add a whack of filter floss in your filter, and rinse it out regularly. That can trap a fair bit of algae. And if the pleco is good-sized, you might need to either re-house it, or increase filtration. When I had a 30 gal. tank, I ran an Aquaclear 70, and that worked well.


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## charles (Apr 21, 2010)

Use a UV, your green water will go away in a day or so.


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## Tazzy_toon (Jul 25, 2011)

Natural sunlight is a big cause of greenwater, i have a 5 gallon that was in my dinning room and my blinds don't close fully, they light from outside caused a great deal of green water. I had to block out the light and do water changes for about a week and hasn't come back since.


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## Bien Lim (Apr 21, 2010)

Charles right!! UV light is what u need!!


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## jbyoung00008 (May 16, 2011)

I agree lots of changes. What did you do with the media in the old filter when you switched? Might be time to lay off all the changes for a bit as it sounds like you may be loving your tank to death. I know I've don't the same and it's a big learning experience

Green water can be a nightmare to get rid of. Easiest way is with a UV light as mentioned. There are some cheaper ones out there that will do the trick. Otherwise start the tank over. You said you were going to buy new substrate. Now would be a good time to remove all the water and start fresh or go buy the UV


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## knucklehead (Dec 27, 2013)

What uv light do i use if my filter is HOB and not a canister type?


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## jbyoung00008 (May 16, 2011)

The green killing machine is an option. I know Canadian aquatics were selling UV's before im not sure what type but they were a good price.. Message Charles or mykiss.


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## charles (Apr 21, 2010)

We have small intank one that doesnt require any canister to run. Contact patrick "mykiss" for more information.


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## greenfin (Nov 4, 2013)

I got green water when I did a big substrate disturbance. Did silly W/C for weeks before bought a UV. My thread on it is called GW and willow branches or something. Some people clear GW without a UV but I couldn't.


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## knucklehead (Dec 27, 2013)

Thanks everyone!


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## Andrew M. (Aug 28, 2012)

I know reviews on them is not the best, but you could go on ebay and order one of those cheaper jebo sterilizers. They are built for ponds but I used one recently for an aquarium and it actually worked and didn't leak. You'll need to supply a powerhead though. As for the green killing machine, I've read articles on some parts of the plastic getting burned and leaching chemicals into the tank, killing the tank inhabitants. I saw King Ed carry it for about 100+ I think.


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## knucklehead (Dec 27, 2013)

I did a 2 day blackout but ended up tearing down the tank for substrate replacement. Will be observing my tank in the next few days.


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## Flear (Dec 8, 2012)

a UV sterilizer is going to be your most comfortable safe bet

blackout is often recommended (never by me) it's hard on your plants, you don't get to feed your fish. may or may not work

or you could ignore it (it will crash on it's own)
i have heard it described by others, i have seen it work myself several times
but i always expect people to freak out because the water in their tank will become scary green before going clear again, ... but it will go clear again, ... then it's like your tank has developed an immunity to it, ... you could intentionally add greenwater and it will die again afterwards.

but the whole "you could ignore it and let it crash itself" doesn't inspire people to feel it's going to be successful at all, ... they feel they should at least be doing something about it right ?

so get a UV sterilizer, ... you'll have done something, and it will work far better than the blackout method too.
just don't get a cheap one, if the water flow is too fast, or if the UV light isn't strong enough you just wasted your money.

(i guess you know trying to do water changes just won't work


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## knucklehead (Dec 27, 2013)

Just an update. So far the green water has not returned and still holding back increasing the hours for lighting. I've also started EI dosing (dry).


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## greenfin (Nov 4, 2013)

Lucky you!


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