Green dust algae on glass

[Aquafreak]

Ok first some tank stats;

40gal
6X30 watt NO Flourescents
35ppm CO2
KH 4.5
pH 6.6

Plants : 80% glosso 2 large green lotus.

Ferts:
1/4 tsp K2SO4 1X week
1/4 tsp KNO3 2X week
1/4 tsp Epsom Salts 1X week
1/2 tsp EDTA Fe 2X week
Flourish 7mls 2X week
Now the PO4, I've tried 4 drops 2X week and I had green dust come backs every 3-4th day after water change, since reading on a post about GD on this board I learnt that 1ml of fleet gives approx. 1ppm of PO4 in a 100L so then I tried 1 1/4 mls 2X week and I get green dust coming back on the 2nd day after water change. I've tried adding it daily to reach 1ppm of PO4 but the algae just keeps coming back. I'm highly suspecting that it's to do with my PO4 but is it too many? not enough?

At every water change I turn off my filter and wipe all this stuff off and I have been doing 70-80% water changes for the past 6 weeks trying to get this stuff off. But everytime it comes back usually on the 3rd or 4th day after water change. I'm fighting a losing battle with this stuff. Someone shed some light.

Thank you for your attention

[Tempest]

Whew, that's a *lot* of light, isn't it? I'm not sure quite how to say you could keep up with nutrients with that much light. I'm not even sure if it contributes to the problem or not but maybe.

[Aquafreak]

I do have alot of light, but after a few weeks of tweaking and testing I don't think that's the contributing factor, however I've found that this stubborn algae is directly responding to my PO4, it increases whenever I mess with my PO4 dosage, but it never seems to decrease whatever I do.

[djlen]

What's your plant load like? How many and what plants?
Len

[Aquafreak]

It's 80-85% glosso and 2 large green tiger lotus. The glosso is growing like mad, each shoot grows a pair of new leaf everyday also the lotus, new leaf continuously.

[djlen]

Sounds like you need more balance, plant wise. You've got a ton of light in the tank and you're fertilizing may need some upping, but I would add some plants. I would add some floaters that will shade the tank somewhat and also suck up some nutrients, and pick some other plants that you like, maybe some fast growing stem plants. You need more balance.
Adding these plants may not go with the scheme you're trying to create. I don't know. But the floaters won't mess it up too much and they do a great job of helping with the balance.
My solution to any imbalance in my tanks is Salvinia or Water Sprite. I love the job they do on excess nutrients.
Len

[Aquafreak]

Forgot i have floating plants, Riccia about as big as 2 hands.

[djlen]

You need mooooooooooore plants. Just my 2 cents.
Len

[Aquafreak]

hehe ok I get the message, but there are no salvini available over here, infact I haven't seen floating plants for sale in hmm 2 years lol. Remember when I tried to get KNO3? well you get the picture. I think I could get some duckweed, but I have an eheim surface extractor, don't think it'll go well with that. Anyway I might try look for some suitable floating plants because the glosso is everywhere, I can't plant anything into the substrate without uprooting some glosso.

[Tempest]

<looks a little confused> I thought your post said 33 gallons early this morning. :D

[plantbrain]

With this much light, you might consider adding more KNO3(3x a week), this should help the Gloss. Adding 1/4 teaspoon will give after gravel etc about 6 ppm of NO3 extra. That should be gone in about two days.

Here's an option that should work although I've had the Green dust go away on it's own a number times by your routine.

Dose the tank well, don't worry about the algae for a few days.
Turn off the filter. Scrub the glass. Let the tank settle for about 10 minutes. Vacuum the mulm off the gravel's surface and slightly below it.
Do the 50% water change. Add nutrients back in.
Black out the tank for 3 days.

Bad news about blackouts and Gloss, the gloss reaches for light when exposed to darkness for more than a day or two.
This can be trimmed down though.

Some pleco's will also eat Green dust like bushy noses etc.
This should harass the algae pretty good.

I have in the past just let the tank go and have not worried about the algae, still dosing what I normally do. It never lasted that long. After a couple of weeks, it went away.

Try this first(let it go, it doesn't attack the plants, just the glass and you can remove it when ever) and dose well. Wait a week or two then scrub it off and do the above routine minus the blackout.

If that does not work try the routine with the blackout.

One of these will work.
Sometimes going with the flow rather than fighting it will work. Let it do it's cycle and then it will back off. Reduce/don't do a water change for a week or two also worked for a couple of folks(similar with Green water issues a few times as well).

Regards,
Tom Barr

[Aquafreak]

Great! :D I'll try some of your methods, I think I'll try sitting it out for a few weeks, increase the KNO3 and see what happens.

Tempest yes it was 33gal, but that was imperial gallons, I somehow keep posting with imperial instead of US, I even got it wrong when I was asking for dosage rates hehe.

Anyway thanks for all the input Tempest, Len and Tom!

[Aquafreak]

I was just thinking, would the daily feeds of frozen bloodworm cubes contribute to this green dust algae? Those bloodworms have PO4 and silicates in them no? I did a 80% water change yesterday, added 2 drops of fleet, fed 1 cube of bloodworm and today the PO4 measured 1ppm, the tap clearly has no PO4 after some extensive testing and local water report. And also I already see the green dust is building up on the glass today, I can see it's gonna be a pretty green week this week.

[Tempest]

I've had this occasionally on a tank but for some reason after I just keep doing the cleanups, water changes, and keeping the nutrients up it seems to disappear after a while. I've got a rubber lip pleco about an inch and a half long in my low light ten gallon that keeps the sides of the tank so clean I never have to scrub them. :) I actually had put it in there to grow up some before I put it in my larger tank but it seems to grow *really* slow. It and the one Oto look nice and fat but neither seem to grow fast.

[djlen]

Yes, many frozen foods will add some PO4 to the tank. PO4 and nitrates are two nutrients that I monitor closely before adding. In fact those two and pH are pretty much all I have to test for regularly anymore.
Len

[Aquafreak]

I think I've found the cause of this green dust algae, where ever there's current in the tank this stuff doesn't seem to grow. I change the outlet of the eheim to a spray bar submerged and the algae has decreased considerably, no matter what I fiddle around with my dosage routine, the stuff won't go away until now. Thanks all for the theories and replys. I think I'm getting the upper hand on this algae after much torture.