I was hoping someone might have some answers for me.
My 15 gallon Goldfish tank has a hair algae problem. Not your typical hair algae issue, either. It grows on one wall of the tank, the filter intake, the plants, and the algae scrubber (which I almost never have to use). It is fully cycled and over 8 months old, using the same lighting since day one, which is Oddysea 24" with bluemoon LEDs for Freshwater (I made sure to buy freshwater). I hardly ever use the bluemoons because I have heard it's not that great for the tank, so I only use them once in a (lol) blue moon, just because it's so cool.
Now for the interesting part. As you can see below, it's likely not a nutrient issue, looking at the size of those plants. It's likely not CO2, due to the bubbler. I do realize that's really inefficient, but I can't afford any better. I haven't "changed" anything, I also only remember to do the water changes monthly, if I'm lucky. The largest fish is my Ryukin, whom is about 2 years old and no more than 3.5 inches. The Shubukin, about a year old, is not much shorter, but has a thinner shape, so is much smaller. I bought an otto to help with the non hair-algaes that my MTS won't clear out, and am considering a molly to mow down the hair, but I realize that can tip the scales in the other direction.
As for the tank stats, it is a 15 gallon TALL, sort of shaped like a thick picture frame. See pics below. The filtration is a non-main branded whisper trickle power filter rated for 40 gallon tanks. I have replaced the carbon section with cotton batton (hypoallergenic, no chemicals added, no dyes added). The filter media gets rinsed every couple weeks. For plants, there is tape grass (As you can see), Hornwort, which is an odd brown-green color and neither growing nor dying, Java moss which is growing like stinkweed, and some failing babies of water wisteria (or watersprite, I'm not sure). It won't root, it won't grow, and it dies off (which I believe tells me that the nutrients are still just fine), if a little low. The lights are 24" HOT5, and pump out 96 total watts for a watt per gallon of 6.5 (about). They stay on 10-14 hours depending on if I get home in time to turn them off. I make sure they get 12 hours of sleep every night and ensure the tank lights aren't on THAT long the next day if they end up staying on too long.
Every time I do a water change, which tends to be about 1/3 to 1/2, adding water conditioner (always!), the algae gets WORSE. I have tested with and without tap conditioner - no difference. I also add liquid plant fert with changes, and be a little on the lighter side, otherwise the algae gets worse. So, I light on the fert, but it doesn't make much of a difference. I also did have a loooooooong hair algae issue, but physical removal along with the fish eating it (and the Java moss and hornwort, lol) has destroyed the long strand hair algae. I now have short algae, and some green dust on the scrubber (and those salt water donutty shape circle things appearing out of nowhere). I did dose with salt for an ich outbreak, but that was due to new plant stress and me being out for the weekend. So, there is some low and almost non-existent levels of salt in there. I can add more, if recommended, as all plants seem to tolerate higher levels of salt. Here are the pics:
The full tank, on my home made shelf, sitting on my side table. Lol.
Mr Wiggles himself, being a camera hog, hovering my my face as he does every time I'm next to the tank. He even tries to eat my finger when I point at him through the glass. Kritterfish is in the corner there. I THINK that's a she; not sure. Mr Wiggles has tubercles, so.
Algae on the intake.
Off-color shot of the hornwort - the flash went off and the image was auto color corrected by my phone, lol.
The algae scrubber.
There are 3 types of algae present, if you can see them: the thin, scraggly green tufts that aren't more than 5mm long, the green spot/dust algae, and that really odd green, thick, tree-like THING that looks like spyrogira... Help?
EDIT: The white dots on the tape grass are bubbles - they collect on the algae, and sometimes release from the plants themselves...WHY, I have NO idea. Also, as you can see, my water is nowhere near yellow or green. It's crystal clear...