Help Green Spot Algae on slow growers, old leaves, and shaded leaves

[Gwad]

Hello all,

I am currently working on a little 10 gallon tank that is pretty heavily planted in a Dutch-style scape.

I am beginning to struggle with green spot algae on leaves and continue to get a little more each day. I also get a lot of green dust algae on the glass, but it sounds like that is pretty hard to avoid for even the best balanced tanks.

The worst are the leaves on my Bacopa, Buce, and shaded lower leaves on my Ludwigia. The Buce is tissue culture and has only had a few weeks to get established. It's not too bad yet but there seems to be a little more algae each day so I am trying to get in front of it.

Specs:
-CO2: approximately 1 point drop using a Yugang reactor
- Light: Week Aqua M450 set to 40% power

Weekly Dosing following the example of @Burr740:
NO3: 18ppm
PO4: 4.8ppm
K: 24ppm
Fe: 0.4ppm using Miller Microplex for other trace elements.
Weekly water change of 50% using RO water remineralized to 6 dGH. I use a baster to lightly agitate and siphon the substrate each time.

Anything stand out that would lead to green spot algae issues? Do I just need to stay the course and continue to trim affected leaves and do my water changes?

For those of you with very well established and heavily planted tanks, do your old leaves still get algae once they get shaded or crowded at all?

Thanks

 

[Burr740]

PO4 gets all the credit for GSA but really anything that makes the plants/or leaves unhappy can cause it. The leaves that have it are not entirely happy. That is the key point to realize. Most likely its pulling a mobile nutrient up from those lower leaves to fuel new growth. Notice its only on the older leaves

On paper you should have enough of everything, but the plants say otherwise. PO4 is the 1st suspect. Is this fresh new aquasoil? All brands will aggressively suck po4 out of the water until they hit a full point. For example 10 ppm can zero out in just 2-3 days.

If this is new-ish soil, Id just dry dose an extra 5-7 ppm po4 after each water change for 2-3 weeks. See how it goes. Its no going to hurt anything if its not the problem

Most peoples co2 isnt as efficient as they think it is. This isnt a typical response to low or poor co2 however. And the plants look pretty good for the most part. There's not a big problem going on

I would do the po4 thing personally. Option two would be what you said be patient and keep doing what you do and see if the issue disappears. It probably will, even if its po4 the sub will eventually stop pulling it out. Do nothing will stretch out the process for a longer time but eventually will get there

 

[Gwad]

PO4 gets all the credit for GSA but really anything that makes the plants/or leaves unhappy can cause it. The leaves that have it are not entirely happy. That is the key point to realize. Most likely its pulling a mobile nutrient up from those lower leaves to fuel new growth. Notice its only on the older leaves

On paper you should have enough of everything, but the plants say otherwise. PO4 is the 1st suspect. Is this fresh new aquasoil? All brands will aggressively suck po4 out of the water until they hit a full point. For example 10 ppm can zero out in just 2-3 days.

If this is new-ish soil, Id just dry dose an extra 5-7 ppm po4 after each water change for 2-3 weeks. See how it goes. Its no going to hurt anything if its not the problem

Most peoples co2 isnt as efficient as they think it is. This isnt a typical response to low or poor co2 however. And the plants look pretty good for the most part. There's not a big problem going on

I would do the po4 thing personally. Option two would be what you said be patient and keep doing what you do and see if the issue disappears. It probably will, even if its po4 the sub will eventually stop pulling it out. Do nothing will stretch out the process for a longer time but eventually will get there.

Great information, thanks. I had heard that aquasoil can absorb PO4 but didn't realize how much. This is newish soil so I will give dry dosing extra PO4 a try for now. I'm always hesitant to add too much anything but if you say it won't hurt, I trust you.

I agree about CO2. Previously I was using an inline diffuser and got a little more pH drop than I am now. I think I am going to make another reactor and aim for closer to a 1.5 point drop to make sure everything is happy.

Thanks!

 

[Naturescapes_Rocco]

Consider using something like the Hanna CO2 kit to check CO2 instead of pH drop! Just a bit more accurate and has less caveats.

 

[Ernesto]

I am beginning to struggle with green spot algae

Hi,
found gsa on my glasses (matured tank) a couple of weeks ago, suddenly.

Looked at it for two weeks, then scraped it off, did a waterchange, and doubled up magnesium from the approx 8ppm tap to 16ppm via epsom salt . (tap Calcium level 50ppm). It did not come back for three weeks now. I'm not 100% sure the Mg level was the reason, but its worth a try. What are your Mg /Ca levels?

 

[Gwad]

Hi,
found gsa on my glasses (matured tank) a couple of weeks ago, suddenly.
View attachment 11348
Looked at it for two weeks, then scraped it off, did a waterchange, and doubled up magnesium from the approx 8ppm tap to 16ppm via epsom salt . (tap Calcium level 50ppm). It did not come back for three weeks now. I'm not 100% sure the Mg level was the reason, but its worth a try. What are your Mg /Ca levels?

Interesting! I will keep it in mind. Unfortunately, I don't know my current Ca and Mg levels. I have been using Salty Shrimp GH remineralizer to get 6 dGH, and they do not publish their ingredients which is very frustrating.

I actually just bought a bag of Calcium Sulfate Dihydrate and have a bag of Epsom salt, so I will be mixing my own remineralizer going forward.

So far I have been dry dosing extra PO4, and I am already starting to see improved growth for all my plants. I am hopeful this is taking care of it but will keep this thread updated for the next few weeks.

 

[hamfist]

Interesting! I will keep it in mind. Unfortunately, I don't know my current Ca and Mg levels. I have been using Salty Shrimp GH remineralizer to get 6 dGH, and they do not publish their ingredients which is very frustrating.

THis is something I foundsomewhere - results of an analysis of Salty Shrimp remineralisers.

 

[Gwad]

THis is something I foundsomewhere - results of an analysis of Salty Shrimp remineralisers.
View attachment 11354

Thanks for sharing that! Looks like they follow a 3:1 ratio. I can't believe it's not officially published. It's kind of a racket with how expensive their remineralizers are. I was just sending this photo to my local group to compare the $30 tub of Salty Shrimp and the $24 I spent getting bags of Calcium sulfate and Magnesium sulfate that will last me many years.