Green dust algae - Algae

Zapins · 04-07-2006, 02:21 PM

I am curious, since i have heard several people complaining of this algae recently. Unfortunately i have it too, and have had it for the past 2 months. Now usually i would not post for algae issues since 95% are easy to get rid of, but this one is proving to be a tough algae to kill.

The algae is single celled and seems to coat surfaces, plants, equipment, wood, glass etc... If left unscraped it forms a jelly-like layer over its surface and continues to grow. The growth rates of this stuff are phenomenal, it clogs diatom filters within a day with spores. I have, as far as i can tell, a perfect fertilizing regimen with automated dosers and light timers etc... i recently raised NO3 to 25ppm and po4 to 3ppm and added a powerful pump to circulate the water and reduce the algae's ability to stick to things.

If anyone has a straightforward EXPLANATION for why this stuff isnt dying in my tanks, or several other people's please do tell. It seems to grow in the same exact range as our plants do making it frustratingly difficult to kill off.

trenac · 04-07-2006, 04:37 PM

I found when I increased my N03 levels that the green dust algae started to grow at a rapid rate. Then once I decreased the N03 levels it starting disappearing, took about 2 weeks.

BryceM · 04-07-2006, 06:03 PM

I would agree 100% with Trena on this. I added NO3 to 20ppm (by a cheap test kit) and had a horrible bout of green dust. I finally checked with Lamotte and actually had NO3 >80 ppm. Two or three WC's later NO3 was ~20 ppm and the green dust went away almost overnight.

Zapins · 04-07-2006, 07:08 PM

Odd, tried that a while back. Didnt work though... My nitrates are in the 20's though so shouldnt that be fine? Also Barr mentioned upping the nitrates a while back, something about it having a narrow living range or something.

BryceM · 04-07-2006, 07:30 PM

Are you sure it's in the 20's? How do you know?

Bert H · 04-07-2006, 07:30 PM

I am having the same problem with one of the tanks and have to say that I don't have high nitrates either. I'm in the 15-25 range using a calibrated Hach kit. I splurged and bought a UV and have it installed, but I think I have to turn down my flow much slower than I currently have to get proper exposure. So far, I can't say I see much of a difference after 4 days of UV. Before the UV, it took 4-5 days to get thick on the glass, seems to be doing the same thing now with the UV.

chiahead · 04-07-2006, 08:00 PM

I have been having the same issue for months it seems now. I have ran the UV constantly for weeks and no change. I doubled water flow through the unit with now change. I let my No3/Po4 levels fall down way low and also had them very high. I am not sure about this one either. Next thing I am going to try is less iron fertilizing. One note is that when doing the excel overdoses a while back it seemed much better, but it came back after the overdoses stopped. I would like some good answers for this one also.

Zapins · 04-08-2006, 02:47 PM

Yes, my 13w UV didn’t help either. And in my friend's tank his 18w UV didn’t do anything. The diatom filter definitely helps a little with the spores but it gets clogged extremely fast so its not so helpful overall. Slow current seems to allow it to attach to things more easily...

chiahead - i also tried excel ODing, i did x3, x4 and x5 overdosing and didn’t really notice much of a difference

this stuff doesn’t seem to respond as easily as other algae.

guaiac_boy - nitrates are in 20's, i know by titration test kits, and looking at visual plant responses. The tests are pretty good with accuracy, they respond correctly with known amounts in test samples.

Hopefully the more people post about this the quicker we can gain a thorough and detailed understanding of this algae, and find way to get rid of it.

plantbrain · 04-08-2006, 05:45 PM

Recently I had 4 tanks going with GDA, I simply stop dosing and let them sit and did not clean the algae off.

The GDA went away in about 10-14 days.

The other way that seemed to work, add a bunch of floating plants similar to a black out.

There's the 3rd option, scrun, then quickly do the large water change, then repeat for 3-4 days. Or scrun one day good,w ater change, then wait a few hours for the film to form, then do another water change that same day. Run the UV if you have one.
Most of these methods work well.

The leave it alone for 14 days seems to work the best, worked on 5 tanks and GDA has not come back since and adding more ferts.

Regards,
Tom Barr

Zapins · 04-08-2006, 07:23 PM

Please bear with me, lots of questions.

Interesting observations, what do you think causes it to come in the first place? What is the trigger?

What do you think about adding a strong current while letting the tank sit? To prevent spores from attaching and growing.

Also do you think doing several water changes all on the same day and not fertilizing for the next few days & then letting the tank sit will hasten the effects of just letting it sit for 14 days? I do not want to starve the plants or have to scrub off the algae film after it forms. Also this tank is on display in the admissions office so having it look nasty is not something i would do unless absolutely necessary.

One last thing, after letting the tank sit for 14 days, does the algae die off? Or do you have to scrape it off?