Green water or maybe not!!

This one is baffling me. Have a 55 gallon fairly heavily planted tank with a JBL CO2 injection kit and 2.8 wpg T8 lighting. Have had this tank running for about 6 months now and have always tried to keep NO3 and PO4 at 10ppm and 1ppm using test kits. CO2 was at about 20-25ppm. I seemed to have a problem with dust algae settling on the leaves, so I decided to do the EI method to save testing all the time and hopefully get rid of the dust algae. Did the water change on Sunday and followed the EI method and also increased CO2 to about 30ppm.

All was well until I came home from work on wednesday and I could hardly see the back of the tank. The tank was full of little green particles, like a suspension. When I've had green water in my pond it was like, well green water, and not like what I have now which is clear water with lots of green particles in - does that make sense?

Strange thing is by about 9 O clock at night the tank is crystal clear without any sign of the green particles. This has now been going on for a week and a half without it getting any worse or better. Did a 50% water change after week 1 and lowered my dosing by leaving a day between the traces and NO3, PO4 dosing in case I was over dosing.

Today I watched what was going on. First thing in the morning the tank is crtstal clear, then as the morning goes on it starts to get cloudy (room is not that bright and tank recieves no direct sunlight). By the time the lights come on at 1 it is very cloudy. Seems to get worse for an hour or two but then starts slowly to clear until about 9 when it is normally crystal clear. Lights and CO2 then go out at 11. CO2 comes back on at 6.

The plants are growing like crazy and pearling away, so am not sure what is going on and what plan of action to now take.

James

 

Re: Green water or maybe not!!

Well I've still got this strange green water. I've kept up the dosing but it seems to be making no difference. I thought that as the tank was becoming cloudy between day break and when the lights come on, the algae was getting a head start on the plants. So today I covered the tank so no light entered the tank until the lights came on. And guess what - a cloudy tank. Seems that the algae is growing in the pitch black.

I don't really want to spend any money buying a UV unit, but would rather find out what this is. My only thought is that perhaps it is dust algae gone mad as the front glass is becoming covered after only a couple of days. Apart from this all the plants seem to be doing very well.

Has anybody got any ideas?? Until then I shall keep up my dosing schedule and water changes.

James