If you want an algae eater rather than a uv stearlizer than go with a bn pleco, SAE, Siamese fling fox or a royal twig act (but one of those might be TOO peacefull).
How many would you recommend I have 6 in the 75 they do an ok job on the hard to get to areas of the glass, but seem to spend hardly any time on my plants.
UV light only effects the planktonic algal cells that pass thru the unit. It does nothing to the sessile algae on the glass.
Its all about ambient light, and nutrients, if your lights are on too long you get algae.
If your nitrate levels are high you get even more algae.
My tank gets about 4 hours of strong sun every day, but because I have lots of plants (aquatic and terrestrial) which compete with algae for nutrients, and do enough water changes to keep nitrate below 10 ppm, algae is minimal. I still have to scrape a little.
Above are terrestrial plant roots from plants growing out of the surface, like the ones below.
I do 30% wc weekly, I do run my lights for 8 to 10 hours I'll cut that back, is in a basement so no direct sunlight, the glass isn't to much the issue and there is no green water. Made the mistake of not Qing plants and I am paying for it, bb came on an anubius and stays in bolbitus I have the bb under control the the stags is still giving me fits.
I dose daily with excel i target tab with root tabs and liquid fertilize after was.
I'll try adding more nerites.
It's only bad near the too of the tank I just keep trimming it atm.
Turn you lights off or limit light cycle to just a few hours. Nerites will eat the hard green algae or brown slime but not the filamentous green or bb.
That is a beautiful tank.