Green dust algae

[evercl92]

I have a issue with GDA. I assume that's what it is, since if I rub it, it will "powder" into the water. It's growing on the glass at a fairly fast rate. I waited 2 weeks (hoping to live out the life-cycle) and it pretty much died and I wiped it off. A week later, it's back again. I would add snails, but my yoyo loaches make it difficult for them to get any work done (though the don't bother the nerites). I'm working on getting them out using a 2L bottle and snails as bait, but it's only working to catch my striated botia so far. It's a start at least.

As of 12/10:
pH 6.8
kh 5.5
iron 1.0
nitrite 10
phos 1.0

I typically add 1/2 tsp CSM+B and 1/2 tsp K2SO4 to the tank 2x/week.
KNO3 dosed to get 20ppm. Fleets added for phos, though I only added it once and that was 12 ml on 10/29. I have pressurized CO2 at about 3-4 bps, 390wt CF lighting, 120gal (4ft x 2ft x 2ft) tank.

Any ideas?

 

[Lonewolfblue]

Low CO2 or Low Phosphates....

I had the same in my 29G, and had asked Tom Barr about it, and that's the answer he gave me. Since I have my CO2 levels up, that left Phosphates (even though the test kit said over 1ppm). So I tested the theory this week. Last weekend, I thoroughly cleaned the tank and some plant leaves, and did my PWC. Then I dosed my regular dosings, but upped my Phosphate dosing. I'm now going on day 5 (tomorrow), and not a spot of green algae yet, and usually at this time I would be seeing it start on the glass. But my glass is clean. I increased my phosphate dosing in my 29G by 1/16tsp KH2PO4. I think it did the trick, crossing my fingers. All other dosings have not changed, and neither has the CO2 levels.

 

[evercl92]

Now that you mention it, that makes sense. I've not seen GDA until recently, and just recently have phos levels gotten so low.

I followed the info here:
http://www.aquariumadvice.com/viewtopic.php?t=80770

I dosed the fleets previously. Prior to fleets, my phos was 0.5ppm. I added 12ml, and it went to 5.0ppm (that's as high was my test goes). According to the calculation, it should have went to about 3.25ppm. So I wonder if the conversion is a little off...

Regardless, I added 7.5ml fleets tonight. We'll see what that turns to tomorrow.

 

[zenkatydid]

lwb, what level is your phosphate at now?

 

[Lonewolfblue]

Approx. 2ppm, but I know it's not correct as when I start getting green algae on the glass, it still registers at least 1ppm. Phosphate test kits are notorious for being incorrect, unless you properly calibrate it first, which I don't do. I also dose EI, so it's not often I test anymore. I just go by plant growth, algae, and fish. And do a 50%-60% PWC weekly to reset everything.

And for dosing, I went from 1/16tsp KH2PO4 to 1/8tsp, 3x weekly. Tank is very heavily planted.

 

[malkore]

my 75 really tears through phosphates, and when I get lazy i have lots of green algae on the glass that wipes off pretty easily.

my CO2 stays about 35ppm, so I bet its your 1ppm of PO4. what brand test kit are you using? if its not a LaMotte, you can't be 100% that the 1ppm is real accurate. I think SeaChem's is a good 'cheap' kit, but it still is only good to maybe +/- .25ppm and that's if you can match the color chart.

just dose a little more than what you were dosing, and see if the dust doesn't come back so quickly...if at all.

 

[Lonewolfblue]

I'm using LaMotte.....
I also have LaMotte for Nitrates as well.

 

[evercl92]

I dosed about 7ml of fleets in the tank on 12/22. I cleaned the glass off 12/23, knowing I would be out of town until today, and using that as a guide to tell if the GDA was coming back. I return and find no new growth (or very minimal). Sounds like I was phos-limited.

 

[Purrbox]

Congrats! Glad that it's working for you.