I have an 80 gal shade pond with a terrible algae problem. Because it gets so hot here, I have two submersable pumps and a two line bubble blower (I can't spell air-e-ator lol).
One of my pumps is connected to a UV sterlizer designed for 600 gallon ponds. It connects with plain black tubing. The water goes through the submersed filter, into the bulb container and back out into the pond. With my first algae bloom I replaced the bulb, having to special order from manufacturer so this bulb is only three months old. How long do they maintain the UV spectrum?
I'm trying natural remedies, i.e. snails, barley etc but it comes back so fast it overwhelms everything. Today will be the fourth time I've cleaned the pond in less than 8 months. When it gets this bad, I take anything I can possible remove, including bottom rocks, scrub off the algae, rinse with well water (same used to fill pond) and replace.
I don't understand why it keeps coming back. And as to what type, I've got at least three in there right now. I had a ton of Elodia, which grows amazingly fast and the algae has killed almost all of it. I didn't think anything could kill Elodia!
Good news is it has been 100% effective at mosquito control, which does make it worth the hard work :)