[wolverinetank]

Hello,

I posted a few months ago about a BBA infestation and didn't provide enough details at the time - long story short I figured out what was causing that, solved the root issue, and now have 0 BBA, but this encrusting, difficult to remove brown algae has now taken over the tank instead. It particularly seems to love the plant leaves and seems to stunt their growth (when a new leaf pops up, it's almost immediately covered in algae - particularly the slower growing ones like Anubias). I can't figure out based on the online resources what type of algae this might be and therefore what the root causes are. I've played around with the photoperiod/intensity and dosing schedule quite a bit and nothing seems to make a difference. Current tank information:

Tank Dimensions: 60 gallons, water depth 11", substrate depth 2-3"

Tank Age: 9 months

Tank Filtration: Overflow system with several layers of floss and activated carbon

Light: Dustin's Tanks Standard Double, currently set to one below the max setting and 7 hours a day

Dosing Schedule: no CO2, EI dosing from Green Leaf Aquariums: 1/4 teaspoon Potassium Nitrate, 1/8 Potassium Sulfate, 1/8 Monopotassium Phosphate, 1/8 Micros, 3 times per week

Water Changes: 50% Weekly

Water source: Tap water with RO/DI top off

Tap Water Parameters: 6 GH, 6 KH, 7 pH, Nitrates ~5 ppm, Phosphates 0

Tank Water Parameters at the end of a week of dosing (before water change): Nitrates ~30 ppm, Phosphates ~10 ppm

Stocking: 3 clouded archers, 2 siamese algae eaters, couple of small danios. Many turbo snails.

Other comments: strong water circulation and aeration in tank (overflow system)


Testing done with API test kits. Any thoughts on what this algae is and how to get rid of it? You will see in the photos below how new leaves are free of it and older leaves are completely encrusted in the stuff. This seems to be the only type of algae in the tank.

Many thanks!

 

[Frshwtr]

Kind of looks like a heavy coating of diatoms. I don't think it's another type of algae.

Just looking through your notes - here is my opinion of what may be causing an issue.

Dosing Schedule: no CO2, EI dosing from Green Leaf Aquariums: 1/4 teaspoon Potassium Nitrate, 1/8 Potassium Sulfate, 1/8 Monopotassium Phosphate, 1/8 Micros, 3 times per week

You're dosing a heavy EI based fertilizer regimen, with high lighting, with slow growing crypts and swords and no CO2. No matter what you do, you are going to struggle with algae. EOW nitrate readings are 30+ ppm. You are not out-competing the algae with your plants and the algae is winning because it grows much faster.

Either dial way back the fertilizer and light and go for a low tech type of setup, or get some very fast growing stem plants and plan on possibly adding supplemental CO2. There is a tough balancing act that has to happen in tanks between light/ferts/CO2 to out compete algae. When one of those is off, everything goes out of whack.

 

[wolverinetank]

Kind of looks like a heavy coating of diatoms. I don't think it's another type of algae.

Just looking through your notes - here is my opinion of what may be causing an issue.

Dosing Schedule: no CO2, EI dosing from Green Leaf Aquariums: 1/4 teaspoon Potassium Nitrate, 1/8 Potassium Sulfate, 1/8 Monopotassium Phosphate, 1/8 Micros, 3 times per week

You're dosing a heavy EI based fertilizer regimen, with high lighting, with slow growing crypts and swords and no CO2. No matter what you do, you are going to struggle with algae. EOW nitrate readings are 30+ ppm. You are not out-competing the algae with your plants and the algae is winning because it grows much faster.

Either dial way back the fertilizer and light and go for a low tech type of setup, or get some very fast growing stem plants and plan on possibly adding supplemental CO2. There is a tough balancing act that has to happen in tanks between light/ferts/CO2 to out compete algae. When one of those is off, everything goes out of whack.

Thanks frshwtr! That totally makes sense. I guess I didn't think what I had was a lot of light but maybe it is. I will try adding a bunch of fast-growing plants and barring success with that, I'll bump the light and nutrients way down as you suggest.

I also ordered a silicate test kit as I've heard that this can be a root cause of diatoms. Are you sure that's what they are? From photos and descriptions I've seen they're supposed to be like an easily removable film right? I've never seen them in my tank like that. They always manifest as a difficult to remove, encrusting, nearly black coating on the plants, hardscape, and glass.

 

[Frshwtr]

Yeah I'm pretty sure that's diatoms. No other 'brown' algae in FW aquariums. Slow growers make it easy for them to collect on the leaves when you never trim or touch them.

When they start encrusting like that, it almost looks red. I battled diatoms that looked like that in my african cichlid aquariums. They would start encrusting on rocks because I had really high nitrates from the huge amount of bioload from a lot of big fish. I also used crushed coral as a substrate which has quite a bit of silicate and would leach into the water. I thought I was growing some type of freshwater coraline algae because they would turn a hue of red over time.

Much of the plants that you have would probably be perfectly happy with root tabs and lower light without missing a beat if you didn't use liquid ferts.

I also just saw that you plan on adding some fast growing stems. If that's the case, then you will need to start slow with the ferts and add more as you see the demand. If you notice they aren't growing well, then slowly bump up the ferts. If you add too much too quick, the algae will explode because it can easily out compete the plants.

I would also highly suggest starting to think about a dedicated CO2 system. Injecting CO2 is a game changer for planted tanks and will easily solve so many issues that people fight with when trying to run low-tech tanks. Automate as much as you can, add CO2 and enjoy the tank without the constant algae battle. That's my 2 cents!

 

[wolverinetank]

Fantastic, thanks a lot! I'll start with some fast growing plants and see how the system responds. I have been avoiding CO2 for years but I'm not really sure why... maybe I just need to take the leap!

 

[wolverinetank]

Yeah I'm pretty sure that's diatoms. No other 'brown' algae in FW aquariums. Slow growers make it easy for them to collect on the leaves when you never trim or touch them.

When they start encrusting like that, it almost looks red. I battled diatoms that looked like that in my african cichlid aquariums. They would start encrusting on rocks because I had really high nitrates from the huge amount of bioload from a lot of big fish. I also used crushed coral as a substrate which has quite a bit of silicate and would leach into the water. I thought I was growing some type of freshwater coraline algae because they would turn a hue of red over time.

Much of the plants that you have would probably be perfectly happy with root tabs and lower light without missing a beat if you didn't use liquid ferts.

I also just saw that you plan on adding some fast growing stems. If that's the case, then you will need to start slow with the ferts and add more as you see the demand. If you notice they aren't growing well, then slowly bump up the ferts. If you add too much too quick, the algae will explode because it can easily out compete the plants.

I would also highly suggest starting to think about a dedicated CO2 system. Injecting CO2 is a game changer for planted tanks and will easily solve so many issues that people fight with when trying to run low-tech tanks. Automate as much as you can, add CO2 and enjoy the tank without the constant algae battle. That's my 2 cents!

Alright, so update. I actually took the plunge and got a CO2 injection setup. I have been injecting CO2 for about 6 weeks now, stopped dosing any powder ferts at all and just put in root tabs instead (since most of my plants are slow growers like swords, java fern, crypts, anubias), and in the last two weeks also cut the light down to 50% power (see initial post for all my tank stats).

My phosphates are now down to 0.75 ppm, nitrates about 20 ppm. Water changes are still being done on a weekly basis.

THE DIATOMS ARE STILL GROWING. They've maybe slowed a liiiiitle bit, and the CO2 has definitely helped a lot with the plants' growth, and they're looking healthier, but new leaves that emerge are still getting completely covered by diatoms within two weeks of emerging.

I'm at my whits end. Any other suggestions? Maybe add more fast growing plants to starve those diatoms of even more nutrients?

Thanks,
Greg

 

[Frshwtr]

That really stinks that you haven't figured out the issue! Have you checked your silicates in the water you are putting into the tank after water changes?

One other thing I didn't notice the first go round - what is the black substrate you are using?

 

[wolverinetank]

That really stinks that you haven't figured out the issue! Have you checked your silicates in the water you are putting into the tank after water changes?

One other thing I didn't notice the first go round - what is the black substrate you are using?

I know! The substrate is seachem flourite black. I just tested the silicates again (salifert test kit) and the tap water comes out to about 1 ppm or maybe a tad more and the tank water less, around 0.5 ppm, which makes sense I suppose since it is being uptakes by the algae (and seems to then not be additional silicate leaching out of the substrate). Is that normal or high?