Help Hair And Brown Algae In An Older Tank


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1 year
Hello there

I have a 20 gallon tank that has been running for about a year and has been consistently stocked for the past 6 months. I've been having some issues with brown algae and green hair algae. From what I've read, it seems that brown algae and hair algae are problems for 'new' tanks, so I'm wondering what I'm doing wrong, and what I can do to reduce the algae.

The brown algae and green hair algae grow on the rocks, driftwood, glass, and live plants. I reduced my lighting intensity and duration a couple weeks ago, but that hasn't seemed to help. I used to have my lights on full blast (Asta 20 planted tank lights...they have a dimming feature) and run them for 9 hours a day. Now, I have them down to about 70 percent intensity (so that it is considered low-medium lighting, PAR-wise) for 8 hours.

I read the main algae post on Fishlore and noticed that one cause of algae is unstable/fluctuating CO2--they recommend smaller water changes. For the past 6 months, I have been doing about 50 percent water changes every 4 days. Is this too much and/or too often?

Other things about the tank:
-I have jungle val, dwarf lily, crypt wendtii, java fern, and water wisteria. They are all doing fine (the java fern is not so great though). I do not use liquid ferts at the moment, but I do use seachem flourish root tabs.
-I have a filter that creates a 2-3 inch waterfall, so I get plenty of surface agitation.
-I have 9 fish (GBR, endlers, furcatas), 2 ammano shrimp, and just purchased a nerite snail.
-Ammonia and nitrites are always at zero. Nitrates have always been at 5ppm.

So, I have 3 questions:
1) Should I do once a week 20-30 percent water changes instead of more frequent big ones?
2) I purchased Easy Green (aquarium coop) and am thinking about using it to boost plant growth. Would this just make things worse, algae-wise?
3) Are there any other things to try? I'm well-aware of SHORT TERM solutions (black-outs, hydrogen peroxide, manual removal), but I'm trying to figure out what's causing it in the first place. I should note that every time I clean/WC the tank, I scrape off as much algae as I can manually.

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