Green water! (from J. Frisco 12/31/00)

[AquariumPro]

Gentlemen;
Although I've had my 65 gallon freshwater tank for 1 year, 2 weeks ago,
I started experiencing a lime - green color change in the water. The
fish seem to be ok. I've change 30 % of the water, but within 48 hours,
it's back to the lime color.
My local supplier suggested that I was getting sunlight
to the tank...I've closed all of the blinds..the ph and nitrate levels
are fine.
Help
Jim

[ReefLady]

By chance, do you have any macro algaes in your tank? Some macro algaes can go *sexual* and turn your water green. Caulerpa is renowned for this, and will usually happen unless housed in a refugium with 24/7 lighting.

HTH,

[oscarbartoni]

Can you tell us what kinds of fish that you have in the tank, numbers, sizes, etc.? Also what kinds of foods have you been feeding, how many times a day do you feed and how long does it take them to eat each time? I ask these questions to better understand what is going on in your tank. Have you added anything new such as fish to the tank lately? Or how about new gravel, I worked in a pet shop for a few years and have heard may different things as to the cause of water changing colors. I hpe that I or some oter menber can find the right solution for your problen so tht you can enjoy the tank. Onwater chages I suggest small water changes often such as 10 to 20% weekly. This is so that any temp or pH changes will be minimal and not cause a large water temp or pH change in the tank. On freshwater tanks when you do a water change you can use the discard water to water any plants that you might have (just make sure not to overwater them).

[slugbug]

It sounds like an algae bloom. Do you have a phosphate test kit? Algae is caused by an excess of nutrients. I would suggest that you keep up on the water changes and feed less. If you are able to spend a little money I would recommend a micron filter. You can leave them running all the time unlike a diatom filter and it will really help to pull suspended particles out of the water. You also might try putting some live bunch plants in the tank even if only for a little while. More complex plants use excess nutrients more efficiently than algae. This would decrease the available nutrients and therefore the algae.