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I have a 72 gallon bowfront tank that recently has been having problems with green water, I'm assuming from algae blooms. I only have a few fish, 3 or 4 Central American Cichlids and a few cyprinids, so and I've done everything from changing the water twice a week, cleaning all filter components, replacing filters, and adding "supposed" green water conditioners that have not even alleviated this problem at all. I have no plants in the tank, but I do have plenty of rocks that have been part of the tank for quite a while now. I thought the rocks might of had a bit of algae build up, so I removed half of them before I recently changed to water. I don't have an over abundant amount of light, less than 6 hours, and don't generally over-feed the fish, so I'm quite confused. Up until a week ago I was absent an algae eating fish in the tank, but recently purchased two plecos who must be feasting their hearts off. If someone could give me advice on what could be the problem, or if I need to be changing the water on a daily basis for a period of a few days to help get fresh water in the tank, please let me know. Thanks all.

Hi,
Yes, if you have green water, then you are having an
algae bloom.

I would do a few things.
I would replace the rocks after scrubbing them off
as they are not the problem and you like their
arrangement as they were.

I would not use any chemicals to kill off the bloom.
That can be dangerous. If you do a massive kill off,
then the water becomes poluted, and the fish suffer.
Then the only way then to aleviate the problem is a
massive water change, nearly 100%, to remove/dilute
the poluted water.

I would continue regular, weekly, water changes of
as much as 30%-50%. Once the bloom is over, I would
drop back to weekly 10-20% water changes.

I would also slow down feeding the fish.

You don't mention what the lighting is and how strong
it is. 6 hours is apparently long enough to watch the
fish while you are home, and then off while out of the
house. Because the photo period is so short, and yet
you have the bloom, it could be that the light is too
strong. Normal photo period is between 10 and 13 hours
(10 recommended). To just view the fish, and not raise
plants, you might want to stick with around 1 watt/gallon.

I would add some floating plants to the water to absorb
and compete with the algae for the nutrients in the tank.
You might also find some of the fish appreciate some
"salad" in their diets. If you elect to do this then
the lights should be around 2 watts/gallon.

The only mechanical thing that will eliminate the algae
bloom is the addition of a UV sterilizer to your filtration
system. That does work. It works well, and fast, and will
maintain the tank. However, it is expensive, and does
not resolve the problems that caused the outbreak in the
first place but, it will eliminate it.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Thanks for the input Frank. I might have used to many chemicals in trying to fix this, just because of the lack of water change after the 20% water changes. I'll try a 40-50% change for a couple of days and hope that will change the water. The lighting I believe is a 100 watt fixture, so after these water changes you suggested I buy some floating plants which is something I will look into. Thanks for the help again.

Tell us the results of a nitrate and a phosphate test...

Start dosing the New Improved Cycle to build a good bacteria colony which will challenge algae blooms.

The average lighting tubes should be around 40 watts each at 10 hours a day.

--garyroland.

--Vero Beach, Florida.

My nephew's tank went through a bout of pea soup. The kid didn't notice that bumped the timer for his tank light and it was on longer than it was suppose to be. I couldn't keep up with getting rid of it.

First I dimmed the tank and kept the room dark for several days and told him to reduce feeding. That was after a 25% water change.

Phosphates tested less than 0.5 and nitrates were 5ppm (not that the algae wasn't eating phos and nitrate making it look lower).

I have a Whisper Diatomagic filter for polishing water. This thing has paid itself off several times. When dimming the tank and doing several daily water changes of 20-25% didn't do the trick, I used this filter. It cleared it up in less than 10 minutes. I went back a week later and it was back. I used the diatom filter again, and this time I used a one time dose of only 15 drops of AlgaeFix liquid (suppose to be 25 drops per 10 gal), and that was the last of it. That was 6-8 months ago and it never came back.

I agree with Frank that if you use a chemical with thick pea soup there could be a massive die off that could cause problems. Using the diatom filter first got about 90% of it out of the tank, then the chemical at less than full dose made sure it was gone.

Unfortnately, my nephew now is battling cyanobacteria. It is difficult keeping up with an 11 year old's tank when you don't live in the house.

Any diatom filter will do including a Vortex or other. They are expensive, but I know people who've had them 15-20 years for occassional use.

http://www.foryourfish.com/cgi-bin/webc.cgi/diatom_filters.htm

Last edited by Cory_Di at 30-Oct-2004 16:45

Thanks for the info Cori, I'll look into it as soon as I get a little extra $$$. The green water has left the tank since my last post, but the water is a little white and cloudy still, hopefully just the tank cycling. I plan on looking at some phosguard for the interim future and just chaning the water once a week at least. Hopefully that will all work until I get the $$$ to get that filter, which looks like a great addition in filtration for freshwater tanks. I always thought that extra filtration would help in freshwater tanks, saltwater tanks using the skimmers in addition to their regular filters. Well, thanks again for the info I'll look forward to a clearer tank one day.