Hair algae problem

[Delphinus]

4 vho? or 2 40w'ers? err sorry now I'm confused, which is which? 4 vho is plenty of light.

This is my advice. You can get by without a good skimmer if you have good tank management practises, i.e., regular water changes. You're better off with "no" skimmer than a "weak" skimmer, so if you get one, do as you are doing, and save up and wait for a deal to come up on one that's used.

If I had to choose between lighting and a skimmer, I'd go with the lighting first, and get the skimmer second (because you can compensate).

Can a BTA get by for a month under low light? I don't know, it's risky. Maybe. You will certainly have to feed it, because it has to get it's energy from somewhere. Try some mysis.

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The hair algae is indicative of a high nutrient load. NO3, and PO4. The algae may be "sucking up" the nutrients so fast that when you test the water for the these, you actually get a zero or low reading. If they were "truly" zero the algae would have trouble growing so fast.

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Here's one thing you can try. Set up a refugium, get some cheap fluorescent lights for it, and stock it up with caulerpa. The caulerpa, being an algae, will suck up the nutrients, and hopefully outcompete the "nuisance" algaes. It likely won't solve the problem altogether, but it can help to slow the nuisance algae down.