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Help Clear Green Water

2398 Views 14 Replies 10 Participants Last post by  Rastapus
Hi :) I have a 90 gallon fish tank with 6 medium goldfish and two bottom feeders, the water in my tank turned green, I just bought a Fluval 405 thinking this will help clear my tank but there is no change, can anyone give me suggestions as to how I can clear this thanks :) :)
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how long do you leave your lights on?
& is there any direct sunlight to the tank?
I just moved into a new place that has a lot light coming through, the fish tank light is on usually in the evening for around 4 hours
it could be the sunlight causing an algae bloom, if it is, try to keep the tank out of the light as much as possible, try to, if you can, cover where the source of light is coming from.

Leave the lights off until the water is clear again, the algae feeds off of light, so as long as there's light it will not go away.. it's a pain my bf and I just had the same problem!
how long do you leave your lights on?
& is there any direct sunlight to the tank?
and after you answer this questions,do big several water changes about 50 - 60 % everyday or every other day until it clears up or use UV light which is an expensive way but it an investment..
Thanks, I'll try doing a 50% water change, in the place i live there is no way i could cover the light coming into the house lol, the place I lived in before didn't have as much windows, a uv light? will that get rid of the algae? thanks :)
UV sterilizer will definitely work but you should really go right after the cause of the algae which is excess light.
Hi Carlinraine, If you can't cover the light coming into the house, perhaps you could cover the back and sides of your tank with something opaque. You can buy lengths of plastic that is intended for this purpose from the local fish store. It usually comes with a plant scene on one side and plain black or blue on the other. This won't work, of course, if you have sunlight reaching your tank from all directions.

It might help to just cover your tank during daylight hours for about a week. Don't turn the lights on at all.

As well, if your tank doesn't have any real plants in it, it might help to throw in some big bunches of wisteria or perhaps hornwort. Those plants grow quickly, don't have to be planted into substrate, and soak up nutrients that algae need in order to live.
Doing water changes will not help you with getting rid of green water. The algae will continue growing and feed from new nutrients that come with the fresh water.
As most people have said, the cause seem to be too much natural light shining on your tank plus you seem to have heavy feeders. There is phosphate in most fish food and by the act of feeding your fish, you are introducing phosphate and other nutrients such as nitrate by process of bacteria conversion. If you introduced recently a new fluval filter, it will help once the filter is cycled and matured.
Just be patient, do water change regularly, wait for the filter to mature, reduce feeding perhaps, try to shield the sides of the tank with something as Morainy suggested to reduce the amount of light.
A UV filter will work to clear the green water but that is like a $80-100 investment. I know some people run it 24/7 and some who run it only when needed. The UV bulb is also expensive when it comes time to replace it and depending on the brand may not be easy to find.
The best way is to try to solve the problem at the source. Even covering the backside and the 2 sides will make a huge difference and is all that is needed.
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buy phosphat remover i have had algee blooms for a while and the only way to get rid of it is to put phosgaurd made my seachem in the filters test for phosphat it causes algee blooms also
I found when I had green water it was so stubborn it drove me mad. Then I invested in a UV filter and it was gone in days. You might consider it, there are other benefits to UV filtration as well.
Had the green water problem for 3 weeks and I gave up the fight and got a cheap submersible UV sterilizer. Green water was gone in 3 days and have not returned and my tank gets a good dose of afternoon sun. I also keep the nutrient in check. I got 2 replacement bulbs from ebay for $20 with shipping. I know UV bulbs aren't made the same, but it does the job for a FW setup and helps keep the pathogens in check. Learned my lesson with submersibles....keep them running 24/7 or pull it out.

Thank you everyone for your suggestions, I went out and bought a UV Sterilizer with Power Head, don't know if I'm running it right though lol is the whole thing suppose to be underwater including the Pump, it doesn't really say where the maximum water level is. thanks
Yay my tank is Crystal Clear today lol the sterilizer helped :)
Out of curiousity, have you checked the hardness levels in your aquarium? Goldfish thrive in very hard water, soft water is also one of the leading causes of green water. Our Goldfish sections in both locations radically improved once we made these adjustments. The UV has destabilized your algae problem but the cause is still present. You should have a KH of 10-12 and a GH as high as 15. Your fish will love you for it!:)
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