View Full Version : Algae Bloom while trying to cycle tank

04-18-2009, 06:33 PM
I'm trying to cycle a 40 gal planted aquarium with 4 Zebra Danio's. It's been four weeks now (three with fish) and I still have no nitrites. I have a algae bloom that has plagued my tank for the last 3 week as well. I'm also doing CO2 injection to encourage plant growth. I even have added some floating plants; Frogbit, Hornwort and duckweed in a attempt to absorb the nutrients and starve off algae. I have also been leaving my lights off, In the beginning I ran them for 8 hours a day with a 2 hour siesta. the green water lightens after about a week with no lights, but never disappears. As soon as the lights are on for a few hours the water become greener. I did a 25% water change (DI) last week and all my levels remain unchanged.

Ammonia: .50ppm
Nitrites: 0ppm
Nitrates 0ppm
PH: 7.0
KH: 11
GH: 5
CO2: 33ppm

Any suggestions or insight would be greatly appreciated, More water changes?

04-18-2009, 07:06 PM
Welcome to the Fabulous AC!
Yup! More w/cs!:22:

04-18-2009, 07:50 PM
Where is your tank sited? You'll have green algae problems, both floating and sessile, forever, if your tank is anywhere near a window. Even indirect sunlight can cause the floating algae bloom.

I know it's counter-intuitive, but if you left the lights on throughout, the plants would have used up the over abundance of nutrients a new tank like yours almost always experience. Vascular plants always out compete algae for nutrients given a chance to do so.

Your Co2 level is a tad high. Back it off to 30 ppm.


04-18-2009, 10:32 PM
My aquarium is not by the window and its in a room that has has the blinds drawn.

I guess I'll return to having the lights on and ride it through.