It seems like everywhere I read green dust algae has either no cause or something different. What really causes it and is it true that the only way to get rid of it is to let it go through its life cycle (~3 weeks)? Just trying to get some concrete answers here!

Thanks!

I can't say what causes it, but I am convinced my problems with it are due to an overly long lights on cycle. I have noticed that it grows only where the glass is in the direct light from either the hood or from the window. I have been using a 10 hour lights-on cycle both times I have had an outbreak of this stuff this year, but just didn't put 2 and 2 together. I have now reduced my lighting time to 8 hours, and I hope I have learned my lesson! So, we will see if that helps once this outbreak finishes its growth cycle.

thanks for the info vaughnH, I am starting to think that is the culprit (i am at 12 hours at 2.5wpg now)

another question... to make the stuff go through its life cycle quicker shouldn't be be leaving the lights on longer?

Tom!! Where are you? It makes common sense to run the lights as long as possible during a GDA life cycle to rush it thru the cycle, and on the Planted Tank forum someone has posted a comment that they tried it and it shortened the cycle considerably. Is that what we should do? I just cut my light period to 8 hours from 10 hours, but if it would rush the GDA to its grave I would increase the time to 16 hours.

I'm more concerned about plant growth than algae wars

Running the lights too long is bad for plants.
Less is wiser than more.

Sunlight certainly exacerabtes GDA, even causes it IME/IMO in some tanks.
Clean tanks often get it, powercompact users, never have gotten in a HQI MH's tank before.

Oh it's there and all, it just never grew.

I think if someone wanted to, they could kill it by doing the 4 day blackout + Excel overdosing(1.5X) with daily 80% water changes and glass wipes+ adding EI nutrients back each time.

That should knock back most any algae pretty good and not cause any issues for plants.

From there, make sure good CO2/nutrients, 10 hours of light etc water changes, no direct sunlight etc.

Regards,
Tom Barr

So it basically comes from light? I knew that because its obviously only growing where light is shining. I have no sunlight shining into my tank and a 65w PC over 26 gallons... How do some people (some have even brighter light!) not get this algae then!
What happened to the let-it-run-through-the-cycle for 3 weeks thing..... I just want this stuff gone, I've got ~25 ppm co2, EI ferts, good circulation... idk what else to do

You can still do the 3 week method, but there's the obvious issue: many will not do it because they are not patient enough.

Light alone is not it likely.
It does not appear to have one driver for germination blooms.
Algae with many life stages often don't.

Sunlight, PC lighting seems to encourage it.

You can slide the lights back, bend the reflectors back etc away from the fron of the glass to reduce the strike.

You will also note, the algae tends to grow specifically on glass, it really does not like the plants and other surfaces to the same degree.

Seems a 3 day balckout and Excel would do the trick with harassment methods of scrubing the glass severl times also during that time.

It's not as tough as green water by any means.

I'm not sure as to the cause that induces a bloom, I've had it never appear in some tanks and others only had it for a few weeks then it was gone, no real patterns.

I've seen it with 110 w over a 50 gal tank many years ago.
We cleaned the tank, in 30 min it came back on the glass.
That tank as not high light really, but was PC lighting.

Regards,
Tom Barr

Thanks for the info tom! Well actually it looks like some is growing on my plants as well...

Looks like you're almost there. What have you got for algae eaters ? I have at least 1 tank Loaded to the I teeth for Bio-Load, and only the Very slightest algae (I see some occasionally). I have to supplement food for the clean up crew on top of 4 feedings a day for the enormous quantity of fish. I don't suggest anyone doing this, but it only goes to prove that algae can be controlled very well by balancing Light, Plants, Co2, and plant nutrition !

Your light cycle is a bit too long. Wattage looks pretty good. Planting looks too light. HTH, Prof M

Thanks for the info! These pictures were about 3 days ago, the algea seems to be getting thicker and more dirty looking and seems to be consisting of little tiny hairs attached to the glass that very slightly move with the current. Do the pictures look good? Here are some shots of the whole tank from about 3 days ago. I think I have enough plants... some are growing sideways as it is to get around other plants for light. There is very very little gravel exposed to direct light. I am going to reduce the light down to 8 hours a day (I think having it on ~12 hours a day is partially what caused this). All I have in the tank is a betta and some randomly appearing snails (I saw a big one this morning) that must have come from the plants.





Should I keep waiting for the GDA to go through its cycle, or do a water change and scrub it... its been a little over a week now. Thanks everyone for your continued help I really appreciate it!