Green Water - Help Please?

[bausman480]

Hi all,

My family is having a huge problem with the floating green algae... And we don't know how best to fix it so that it doesn't return.

It all started in july - by that time we've had our 90Gal aquarium set up for about 6 months. The light was turned on consistently for about 4-6 hours a day in the evening, and off the rest of the day. We've always consistently fed the same flake food in the same quantities, twice a day.

No new fish additions happened during that time. The room also got no sunlight (it has a window on the other end of the room, but it was covered with drapes all the time). Then, over the course of about two weeks, the water became completely green, we couldn't see the fish a few inches away from the glass.

Small, 20%/day water changes didn't help. The water just became greener and greener once we stopped with the daily changes. Drastic water changes (with relocation to a new aquarium, cleaning out the 90gal, putting fish back in properly) didn't help - the water became pea-soup green in a week. We tried not turning on their aquarium light for a few weeks - didn't help. We tried reducing the amount of food we feed by more than half - didn't work. All three together (water changes, reduction of food and elimination of light) did not stop the pea-soup from coming back.

We have since moved to a new house. Since you can't move the 90gal without removing the water, we had to set up a new tank. After the fish went in, it took about week for the pea-soup to come back.

These are the fish we have in the 90gal. There are no live plants of any kind. One black moor goldfish about the size of a fist, three small brown-algae eating fish (I forget their name... they're golden in colour and have pink "dots" on their head), 5 silver dollars, 2 gourami, and about 4 small random fish... different coloured mollies.
So you can see there is not enough fish to over-crowd the 90gal aquarium...

Also, we'v tried moving the fish to an aquarium with nothing - no rocks, no gravel, no plastic plants. Just the fish. And the water would become pea-soup-like again in a matter of weeks.

We really don't know what to do... There are several ways of eliminating the algae, but we dn't know what's causing it, so it just keeps coming back.

Please help?
Alla

[bluerose]

I would suspect it is your filter that is your 'contaminant'... with all the moving around you've done though I would watch for a cycle.

If this is Green Water, one of the more effective treatments (I think) is to do a large PWC, leave the tank completely dark- not just lights off, lights off and tank covered, not even to feed the fish (they'll be fine for several days)- for 4-5 days, then do another decent size PWC. There are other things as well (such as a UV sterilizer) but this treatment works well or so I have heard (and is cheap).

I would wait for the experts to chime in though- I have never personally dealt with Green Water myself.

[bausman480]

Hi Bluerose,

Thank you for answering.
We have a stand-alone filter (the box kind that stands below the aquarium) that was advertized as enough to maintain a 120gal. It has layers of different sponges, a layer of carbon, and a layer of phosphate absorbing crystals. We clean out the filter about once a month.

I read somewhere that covering the tank for a few days doesn't get rid of the algae, but rather just turns them colourless, and they turn green again as soon as there is any light... Is that true?

[Tommy Gun]

Hey Bausman480 ~ sorry to hear about your troubles.

Generally, algae blooms like this are caused by too much light (which includes natural light, such as sunlight from a window) or an over abundance of nutrients such as nitrate and/or phosphate...or, of course, both too much light and too many nutrients. In order to help you better, it would be very useful to know what your water parameters are, if you do, in fact, test for things such as ammonia, nitrIte, nitrAte, phosphate, pH, etc...etc...etc...

The thing to keep in mind here is that algae differs from plants in that it gains all of its 'food' from the water so these water parameters are going to be essential in your finding the cause, the "cure", and then preventing the problem from coming back.

I read somewhere that covering the tank for a few days doesn't get rid of the algae, but rather just turns them colourless, and they turn green again as soon as there is any light... Is that true?

I'm not sure if that is true or not, but I can tell you that it does work. In conjunction with removing all of the light that the algae benifits from, the reason bluerose mentions that you should avoid feeding the fish is because this means no new nutrients are being produced, while at the same time, the huge population of algae is exhausting what is currently available. So, in reality, this is a two-pronged approach.

Out of curiousity, what type of lights do you have over your tank?

We've always consistently fed the same flake food in the same quantities, twice a day.

You may want to try feeding only once a day...which means you would cut the amount of food you are feeding now in half. Despite the appearance of your fish looking/acting hungry, eventually you are creating a scenario much like Pavlov's dog in that your fish recognize humans as being the dinner bell when, in reality, they can live easily, and in some cases, be much more healthy when eating what they should eat versus as much as they can eat. This is made more important by the fact that we are keeping our fish in a very tiny body of water (relatively speaking) that can become polluted in very short order if we are not careful.

Additionally, it is important to understand that even if your fish eat every last bit of food (i.e. none is decaying in the water), the food is still making an impact on your water quality, only this time, in the form of fish waste.

[CaptainAhab]

How often do you gravel vac? Those sponges in the canister should be cleaned (rinsed in dechlor or tank water) at least every 2 weeks. Have you tested your water for nitrate and/or phosphate readings? When was the last time you changed the carbon and the phos crystals?

Might also be worthwhile testing your tap water for nitrates and phosphate. That will give you a good idea of where your starting point will be. Ro or distilled would probably be better but you should be able to get by just fine w/ tap as well.

Something is feeding the algae, the key is to find out what and rectify it. Covering that tank will get rid of the algae you have now but the root cause still exists and it'll just come back, that's what needs to be fixed

[CaptainAhab]

Nice call on the lights. What kind and possibly most important how old are the bulbs

[Tommy Gun]

how old are the bulbs

Exactly what my next question would have been. Hope I didn't throw anyone off too much by editing my post five times in four minutes. Not used to such an active forum!

[bausman480]

Tommy Gun, CaptainAhab, thank you for replying.

One correction - the crystals in my filter are ammonia-eliminating, not phosphate-eliminating.

Unfortunately, I do not have many testing kits, but I do have pH and phosphate. I just tested right now, and I got 6.6-6.8 pH and 2.0 ppm Phosphate.

I'm going to go in order of things posted.

Out of curiousity, what type of lights do you have over your tank?

The light bulb says 32 watt, fluorescent. Its about 10 months old.
Its only been in use for a few hours a day though, if that matters.

Despite the appearance of your fish looking/acting hungry, eventually you are creating a scenario much like Pavlov's dog in that your fish recognize humans as being the dinner bell when, in reality, they can live easily, and in some cases, be much more healthy when eating what they should eat versus as much as they can eat.

Thing is, our aquarium is in the living room, the room where we are most often during the day... So its not a Pavlovian response to seeing humans, its more of a response to the time of day.. Because in the morning they are all excited and crowd around, swimming actively until you feed them. As soon as they are fed, they don't care about people coming up to the glass tank. Same thing at about 6 PM at night - they start going crazy until you feed them, and then don't care once they're not hungry.
Are you sure they'll be fine fed regularly once a day? Because we really don't give a lot per feeding... we've actually been a little bit paranoid about overfeeding since struggling a lot with that in the beginning, when we got our first 20gal.

How often do you gravel vac? Those sponges in the canister should be cleaned (rinsed in dechlor or tank water) at least every 2 weeks. Have you tested your water for nitrate and/or phosphate readings? When was the last time you changed the carbon and the phos crystals?

Gravel vac - err, I'm not sure.. about as often as we do PWC, which isn't that often. Maybe once a month? Rarer? Yeah, we definitely rinse the sponges less regularly than once in two weeks. I have tested for phosphate (see above), I don't have a nitrate testing kit. The last time we changed the crystals was... a month or a month and a half ago.

Might also be worthwhile testing your tap water for nitrates and phosphate. That will give you a good idea of where your starting point will be.

I can't test for nitrate, but I will test for phosphate momentarily.

[CaptainAhab]

2.0 is medium high in the phosphate but I'm just guessing that your nitrates are whack too. If you have a lfs near by, get a sample test. If they have liquid over strips push for that test. BTW: A nitrate test kit is one of the more important ones.

I'll also assume that the light tube is a garden variety one? You might do well to replace it w/ one meant for an aquarium.

[bausman480]

I'll see if I can get a nitrate kit. Why is it one of the most important ones? How do nitrates affect the aquarium? What do they influence? Because going out and buying something is a huge problem in my house, and I have to justify purchases that I want to make to my parents.

The light tube was from the aquarium store (Big Al's, if you know it), and it said on the box that it was specifically for aquariums..