Trimmed Plants = Green Spot Algae

PhillyB

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Dec 27, 2006
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All,

I have two tanks. A 29 gallon with injected CO2 and a 10 gallon using Excel. The 10 gallon is ALWAYS in better shape and nicer looking because the 29 gallon has been plagued by green spot algae. This is the only algae that I ever seem to run into with this tank. It appears to occur whenever I trim the plants. The trimmed plants will have GSA on a few of the leaves just below where the trimming occurred. The GSA is also prevalent on my micro swords which cover the foreground. Why does it appear consistently on the leaves below the trimmed point?

Light = 65 W of PC. It is on two 65W bulbs that switch half-way through the day.

Ferts
3x a Week = 5ml Tropica Master Grow; 1/4 tsp KNO3; 1/16 tsp Mono Potassium Phosphate;
Daily = 5ml Excel.
1x a Week = 1/8 tsp Potassium Sulfate; 1/4 tsp Magensium Sulfate; 1/2 tsp Calcium Sulfate.

CO2
Compressed. Drop Checker at a light green with 4 deg. KH solution.
I run the CO2 line into a RIO 180 to chop up the bubbles. The air intake of the RIO is also re-routed into the impeller.

Circulation
1 RIO 180 for CO2. Another for additional circulation. (2 x 120 gph)
FLUVAL 205 (180 gph) hooked into a Spray-bar.

Any comments / suggestions are appreciated. When I do a water change half-way through the light cycle the plants pearl intensely. I only notice moderate pearling during the day w/o water changes.
 

VaughnH

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Why do you let the powerhead suck air into the water flow? Air will not help with CO2 injection. Did you use distilled or deionized water for the drop checker?
 

PhillyB

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I am not pulling air into the power head. I mean to say that where the air intake (ventrri nozzle?) would be I routed that back into the impeller. I figure this would allow a bit more CO2 to enter solution in the water. So, the only gas going into the power head is CO2.

I used distilled water in the drop-checker.
 

VaughnH

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When I had a 29 gallon I ended up dosing about halfway between 1/16th and 1/8th tsp of KH2PO4, in order to prevent green spot algae. So, you might try that. From your description it seems like low CO2, but the drop checker seems to be saying you have 30 ppm or so, which should be right. Now I understand how you hooked up the powerhead, so that seems all right too.

Do you dose KH2PO4 the same time you dose the trace element mix? If so, you might be precipitating out the iron and some of the phosphate.
 

Tom Barr

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I'd still focus more on CO2, if the PO4 is up as well, you should not have GSA issues.

If you get GSA or any algae after a trim etc, do a large water change right after the trim or any work inside the tank as a rule.

also, when you change the water, make sure the drop checker is changed at least once every week or two, keep up on that also and realize..it's got a 2-4 hour delay in color resolution.

So some tweaking with your eyes and watching the plants,, should help.

Regards,
Tom Barr
 

PhillyB

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I have been doing 1/16th of a tsp 3x a week on alternative days from the micro nutrients. So, I don't think the combination with iron should be an issue. My tap water comes out at ~ 2.0 ppm, so I am thinking 1/16th tsp should be just fine.

I will look into the CO2 more thoroughly. I have not been changing the drop checker solution bi-weekly as suggested. Also, the lights/CO2 kick in while I am at work. I note a YELLOW color when I get home. Perhaps, the 30ppm of CO2 is taking longer to establish in the tank. I will see about having the CO2 kick in a little earlier or alternating my diffusion methods.

Thanks.
 

Tom Barr

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I'd just check the CO2 good.
Sounds like the rest is okay.

GSA is a PITA and I'm glad I no longer have to deal with it.
Still, it's a two cause algae.
CO2 and PO4.

I think there might be another method also to get rid of it over the longer term also.
But the above does work over a wide range too.


Regards,
Tom Barr
 

PhillyB

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Tom Barr;21252 said:
GSA is a PITA and I'm glad I no longer have to deal with it.
Still, it's a two cause algae.
CO2 and PO4.

When you state PO4 as a cause, you specifically mean a lack (or low enough to inhibit growth) of PO4 correct?

Tom Barr;21252 said:
I think there might be another method also to get rid of it over the longer term also.
But the above does work over a wide range too.
What is the other method you are eluding to? I know when it is on the glass you can wait a few weeks and then clean it off. Is there another method for it when it appears on plants?
 

VaughnH

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Green spot algae and green dust algae are completely different. It is GDA that can be allowed to live out its natural life cycle before cleaning it off the glass. GSA forms small circlular spots on the glass and leaves, which grow to much larger sizes. Those need to be scraped off the glass, and if the amount of phosphate dosage is increased it will often stop it from coming back. I'm curious about the other method too? A blow torch???
 

PhillyB

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Another question in relation to this...

The GSA looks to be dead sometime after it appears. It turns a very dark green, maybe even a black color after some time. If it is in fact dead, will it eventually fall off of the leaves? I tried to rub it off with my fingers but it persists. I am wondering if I am stuck with the algae on the leaves it has formed on. Is my only alternative to uproot and replant the plant tops?
 

VaughnH

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Once a leaf has been heavily infested with green algae I think you do best to get rid of it completely. I can't think of any time that I have been able to make a leaf recover. Even when the algae on that leaf dies, the leaf is still in such bad shape it soon gets more algae growing on it. This is one of the good reasons for pruning by getting rid of the bottom part of the stem and replanting the top part. I need to do some of that too, and as soon as the new filter outlet fitting I bought arrives I will do so.
 

Carissa

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GSA is the only type of algae I haven't been able to figure out how to conquer yet... but thankfully it doesn't grow on my plants, just on the glass. Probably my diy co2.
 

Tom Barr

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And you'd be correct.........if not PO4, then CO2.
Those are the only things that have seemed to cause and get rid of it I've seen.

As with any cause, there might be more than one, same for BGA..........but not as likely for others.........

Regards,
Tom Barr
 

crystalview

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I know this is an old post but I have a question.
My Anubias which is about 8" tall has GSA on all of the leaves and it covers 3/4 of each leave. If I go by what was said above. I need to trim the leaves and plant the top, but my top has GSA also. Could I put the plant in my hospital tank and cure it of the GSA with more PO4? Or should I just leave it in the tank and increase the PO4. My old tank only had GSA on the glass.
I have not tried to rub it off like I done with Diatoms. Would rubbing help? Are Anubias prone to GSA because of their slow growth?
 

VaughnH

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I find anubias prone to just about every algae because of their slow growth. The one that is the killer is BBA. You can't rub off GSA and you have to work just to scrape it off the glass. Anubias are pretty hardy plants, so why not just lift it out of the tank and sprinkle KH2PO4 on the leaves, wait a few minutes, and put it back in the tank? If the alternative is removing the leaves, you don't stand to lose much by trying that technique. Tom reported that sprinkling any of the fertilizer salts on hardscape items kills the algae on them, so it might work on leaves too.