kk07

Lately after my tank has been clean and everything seems
okay about four days later my water turns greenish. I don't know whatelse to check. My fish seem fine. What's going on?

Tommy Gun

Welcome to the forum kk07!

Well, the good news is that this is an issue which is pretty common and it is very likely that your fish are not completely in jeopardy. To keep it simple, the greenish tint in your tank is caused by algae; specifically a single cell algae I believe. That said, there are a few things that you can do here, but it would help to know a little bit more about your situation as a whole, such as:

How long has this tank been up and running (is it cycled?)?

How many and what types of fish do you have?

What are your water parameters/test results for ammonia, nitrite, and nitrate (and any other items you may be testing for)?

What is your maintenance routine with this tank? For example, the frequency and amounts of changing water, etc...?

What are you feeding your fish and how often/much are you feeding them?

Do you have plants or any other livestock which needs light to survive?

Is your tank located near a window or otherwise receive sunlight?

YesimTHATjeremy

hey lemi tell u this is so common its not even funny so lemi just say its easy to fix. change somewhere between 35% and 50% 0f the water and then change the filter. oh and a quick merical(omg i cant spell) cure buy a bottle of "mardel's water conditioner "Brite N' Clear"" fallow the instructions and ur troubles will be over. good luck ---Jeremy

Tommy Gun

I agree that it is pretty easy to fix and I apologize for not getting into this within my initial post, I was short on time. However, these commercial (by the way, there is a spell check feature on the forum...looks like a check mark with 'abc' above it) products might help 'fix' the problem for the time being, however, they really can't stop it from occurring again. This is not to mention that some of these products are just as harsh on your fish, inverts, or plants as they are on the algae which is causing the greenish tint, so, IMHO, they should be used in only extreme cases, if at all.

In newly established tanks, especially those which are still cycling, algae blooms and bacterial blooms (a milky-white type discoloration of the water) are common because the ecosystem we are trying to recreate is still unbalanced. In fact, many people associate these blooms with cycling directly, however they can happen to any of us at any time if we allow the right conditions to occur. For example, overfeeding, using too much light, keeping lights on too long, not performing frequent enough/large enough water changes, and things along those lines can trigger algae blooms.

That said, a water change will certainly help, as it has for you, but you must also change something else so that the green water doesn't come back. One of those things might be to turn off the lights and cover the tank so that no outside light can reach the water for 72 hours. The idea is pretty simple...algae is photosynthetic so no light means it cannot thrive. You can also try to reduce the other items which the algae is feeding off of such as nitrates and phosphates....in fact, you might want to check your tank for phosphates as well as the water source you are using to see if it is a contributing factor to the algae blooms. A UV sterilizer is also an option, but not usually economical in that there are easier, and free, methods of dealing with these problems.

The good news is that in most cases, both bacterial and algae blooms have a sort of 'roller coaster' life; meaning when the conditions are right, they thrive and multiply like crazy...but as the population explodes, the rate in which the nutrients are being used up also increases at the same pace, so, over time, the population 'crashes' and the problem disappears. Again, that is only good news in the short term though...prevention is by far the best 'cure'