Green water - or am I going nuts?

[jsoong]

I have a bit of an algae prob in my 10 gal for the last few weeks, not too thick, but definitely green water. Other para: NH3 - 0, NO2 - 0, NO3 - 5, few plants, 33 watts flourescent light, 2x 1" Ryukin.

One thing that is buggin me, the amount of green water change over the day. At night water appears clear, but over the day it gets more & more green, only to disappear by 9 or so at night. (This is with the light on. ) The tank is opposite a North facing window (about 8 ft away), so is not getting much sunlight. Only thing that change day to night would be temperature. This is unheated goldie tank, & day time temp is 70's, down to 65 ish at night.

Is this normal behaviour for algae to play hide & seek? Is this an optical illusion, or am I going nuts?

It seems every night I got mad enough at the algae to consider some chemical solution (other than increased water change I am doing now), the water clears, only to reappear next day! :?

 

[RogerMcAllen]

Optical illusion I would think. Perhaps you have high phosphates. My reccomendation would be to get some simple plants to use up all of the excess nutrients so that the algae can't compete.

There is a thread somewhere on here about someone who used duckweed to help. You could just take some of it out every once and a while as a nutrient export. You probably wouldn't run into too much of a problem with it taking over the tank as I think goldies love the stuff.

 

[jsoong]

Watched it a couple more days. Don't think it is an optical illusion. Took some water out 1st thing in morning, crystal clear. Clouding up as day goes on, definitely green tinged.

I am now wondering if this might be some sort of bacteria bloom that is changing with temperature. I don't think algae can grow/die that fast.

Any ideas?

 

[dralarms]

Maybe put a heater in the tank, keep it @ 70 all the time. but I dare to say that if it's changing 5 degrees then you are getting sunlight from some where. and that will cause the green alge.

 

[jsoong]

Oh, the 5 degree change is from the house temp - I have a set back thermostat & keep the house cooler at night. Plus I have 33 watts overhead so that is increasing the temp too.

Yes I am thinking of a heater, tho I am saving that for my bigger tank "under construction". The 10 is going to act as my QT once I am done.

 

[browneu]

The green water that you are seeing isn't an illusion but unicellular algae. It is due to the excessive light that you have. As far as I can tell you have 66 watts for 10 gallons which is 6.6 watts per gallon. Unless you only have one light at 33 watts which is still 3.3 watts per gallon and is still considered a high light tank. What is happening is that during the day the algae is multiplying causing your water to turn green. Then the algae dies off at night when there are no lights to encourage growth. There are several things to get rid of it but it will come back if the imbalance isn't cured. I would definitely test for phosphates. While it isn't necessarily true that phosphate may cause an algae bloom, algae can absorb and feed off the phosphates much easier than plants can. I would also add some more plants and start to dose CO2. Basically, you should try to do anything that would help with plant growth and eventually the plants will out compete the algae and algae growth will diminish. Here are some things that you may want to try as a short term solution for your green water.

1) A complete blackout for several days. The lack of any light will starve the algae and your tank should become clear. You will need to watch your ammonia levels since the dieing algae will quickly fowl the water.

2) Purchase a UV filter. The filter will kill any free floating algae and bacteria in the water. Again you will need to watch you ammonia levels since the dead algae and bacteria will quickly fowl the water.

3) Puchase a diatom filter. The filter will quickly filter out any free floating algea and anything as small as one micron in size. Since the impurities are filtered out there is no need worry about any ammonia spikes.

Sorry about the long reply and hopefully this will help.

 

[jsoong]

I have just one 33 watts light, and yes I know that is a bit much for a 10 gal. However, that is a light I happened to have kicking around & I figure I'll use it. Also, when I first read about planted tank, the suggestion was for 3-4 watts/gal.

I first thought the green water was algae as well. However, I was not sure if the algae will die that fast just with temp or light change over the day. I thought green water takes a few days of no light to clear, but this is clearing just a couple hours after sunset - and with my light still on. ... then it's back by noon or so next day.

I am trying to go pretty low tech for this tank, so for now it is water change, and I am cutting down on the light & see what will happen.

Actually, I am finding this pretty fascinating - disappearing/colour changing algae or whatever - almost as much fun as the fish.. But I wouldn't want to have murky water all the time.

 

[TankGirl]

I agree that phosphates might be the issue here. I also agree that one of those Hagen CO2 units would be a boon in that tank. This will enable the plants to outcompete the algae for nutrients. I have also had some success with adjusting my lighting on a timer, so that it is on for 5 hours, off for 2, then on for another 10. For some reason the plants are not bothered by this schedule and the algae has trouble keeping itself going. My phosphates are currently about 0.5ppm out of the tap, so water changes was actually putting more phosphates in the tank, and not really helping. I did start using a phosphate removing media in my filter, but it was the lighting schedule that turned the corner for me. Good luck!

P.S. The water temp could be playing a role in plant growth, since most are tropical and do best in warmer water. Another thing is that those fish might wind up consuming your plants!

 

[tkos]

Yes, high light without equally high CO2 will just lead to algae. Of course thelight by itself won't do anything unless there is excess nutrients. You may not get high ammonia or nitrite or nitrate readings because the algae is using it up really fast.

Perhaps as was mentioned fast growing plants like duckweed, watersprite or hornwort would help. This water won't hurt the fish in and of itself. But it could be a sign of something worse happening.

Cut back on feedings, do partial water changes every day and as was mentioned cut out eh light completely for a few days.

By the way green water is excellent for fry. Good source of nutrition.