Green water/algae problem

[auntiejeffer]

For many months now, the water in my 55 gallon freshwater tank has been very dark green. The rocks, decorations and (fake) plants are all algae free. I tried to test my water - the only test available locally to me is a "Jungle" brand Quick Dip multi-test kit. I was quite surprised when everything tested fine (according to that kit).

(Sunlight does not hit my tank, and there is no heater vent, or any heat source, next to this tank. Also, it is not a problem of the fish being over-fed).

I contacted a pet store and they sold me a bottle of "AlgaeFix". They said the algae particles in my water are so small that my filter will not catch them, and that this product would "clump" the algae together and my filter would then catch it.
I used this product every 3 days as recommended. I could get the green color to lighten a little - but then every time I did a partial water change - the dark green color would come right back. (My filter is large enough for an aquarium this size).

I only have 3 fish in this tank, and they are doing great! I don't remember what kind of fish they are, but they've grown a lot, even with this green water problem. If it would help, I could try to get a picture of one of the fish, and post it on here, too - but I can't imagine that would make much of a difference.

I currently have 3 other tanks (two - 30 gallon tanks, and 1 that is approx. 20 gallons). None of these three other tanks have any kind of algae/green water like this. (I do use the same water conditioner in all of my tanks, so this should not be the problem).

I tried to search for online help suggestions, and read that I could try covering the tank for 4 days, so that is gets absolutely no light. I did that, and there was absolutely no difference at all.

There is probably information that I am forgetting to mention, but any help offered would be greatly appreciated!
Thanks so much!

[Brhino]

that is indeed some awfully green water!

How often do you do water changes, and how much do you change when you do?

A series of daily large (75%+) water changes should clear it up in a few days, but it may come back if whatever's causing it in the first place isn't changed. Since you say it doesn't get direct sunlight, I'm not sure what the issue is. What kind of light does the tank have, what wattage, and how long do you leave it on per day?

[Lady Hobbs]

You say your filter is large enough for a tank this size but do not say what it is. Many filters are said to be enough for certain sized tanks but in fact are not.

You need to do more often and larger water changes until you can get this tank back under control. This aglae is lowering your oxygen levels for your fish.

[auntiejeffer]

Thank you so much for the quick responses (it did take me a little while to get back here to reply).

To Brhino:
I do a 50% water change when I clean the gravel. I know I don't do them as often as recommended, but normally my tanks keep very healthy/clean looking. I've never had any green water before. Once in a while, one tank will get just a little "cloudy" looking, but I made sure to do a water change immediately, and the water went back to looking nice and clear right away! I will start doing water changes more frequently (especially on this tank!!)

Would it be safe for my fish to do a 75% water change on this tank daily for a few days? I've never dared change it that often, to get rid of this algae problem.

The light is a 48" (single-bulb) light strip. The bulb says...
All-Glass Aquarium
32W Aquarium Lamp
(that is the only writing I can see)
(and the bulb is only about 10 months old)

I've only recently started using a timer for my bulbs. I have it set to turn on at 8am and off at 10pm.

Thanks so much for your help!!

To Lady Hobbs:
My filter is an Aqua-Tech 30-60. I'm sure this is considered to be quite an outdated style of aquarium filter, but they've always served me well in the past (and I can buy them, as well as the refills, locally).

A couple of my other tanks, I have changed to a Whisper Internal Filter (which run quieter, and do a great job keeping the tank clean). I can also buy this (and refills) locally. Do you think it would be worth switching to this Whisper filter for my "problem tank", or do you have a different recommendation for a filter? (Although I cannot buy any crazy expensive model!) :)

Also, you said this algae is cutting oxygen supply short for the fish. Would a bubble stone help? Or would the algae like that more than the fish? Or wouldn't it make much of a difference anyway?

Thank You, too, for the help!!

I really do appreciate both responses!!

[Brhino]

daily 75% water changes will be fine for the fish, as long as you're not swinging the temperature too much when you do so. Your light is not very powerful but you are leaving it on for quite a while which I'm sure is contributing to the algae problem. Since you don't have live plants, the only time you need the light on is when you want to look at the fish.

[auntiejeffer]

Ok, I will get to work on the daily water changes. And I'll reduce the time on the lights.

One thought I did have was if I should remove all of the gravel & plants until the algae is gone? I didn't know if that would help or not. Or, since the plants are fake, if any of that would even be a contributing factor to the algae.

Thanks, again, for your help!

[DrNic]

A while back I had one tank that did this (out of 5 in the room and 8 in the house). Only one went green and I could never figure out why. I did the same thing that you did with the algaefix and similar products but nothing seemed to help. Eventually I just gave up. I completely drained the tank, rinsed the tank and gravel really well with tap water, then refilled the system and started over, making sure to add algae cleanup fish along the way (a pleco and a handful of mollies/platties). I left the fish in a small quarantine tank for about a month to make sure they weren't going to carry any algae back into the tank. When I was satisfied they went back in. After the 'reset' everything was fine but I never did figure out why it happened in only one of my tanks.

If you really don't want to break down the tank I would seriously consider just turning the lights off for 7-14 days and wrapping the tank in black cloth or paper. The algae shouldn't survive that long without light and it might give you the advantage. Not sure how the fish would like it though.