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fish tank turning green

7K views 4 replies 5 participants last post by  Tracy 
#1 ·
i have a 20 gallon tank and would desperately appreciate some help. i have only an oscar left in it as all of the fish keep dying. the water keeps turning green. i have changed the water and cleaned everything twice and within 3 days it is green again. i did a quick dip test strip on it and it says water is 300 ppm for hard water. will this turn the tank green and what can i do to correct my problem?
 
#2 ·
Hi,
Green water means an algal bloom has occurred.
Where is your tank located? Is there direct sunlight?
If you have lights, how many hours do you leave it switched on?
To remedy that you may need a blackout for 3 days or more. It means covering your tank with black materials and no peeking on the tank to stop the light from penetrating the tank which can worsen the situation.
Is the 300 ppm nitrates? If so, it's very high but can be remedied with more water changes and addition of plants like elodeas and hornworts.
Good luck.:)
Pls try to test your tapwater if it has nitrates. It's quite unusual that you had 300 ppm(if this is really nitrates).
 
#5 ·
Hmm, I work part time in a pet store and had the same question from a customer today, about the water turning green every 7 days. It also happened in one of my tanks years ago. Although I do not remember exactly how I got it to go away, changing the water only makes things worse. I agree with keeping the lights off for a few days, covering the tank to keep the light out. I read in a book that a couple of aquarium plants in the tank (after the 3 day black out), may use up the nutrients that the algae uses to strive. Try the black out, then live plants.
 
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