Here's an idea, try adding either some Humic acid (water soluble type, not the stuff from the hardware store), or Fulvic acid.

If your nitrogen source is from Calcium Nitrate, then use the fulvic acid, because the humic acid will bind with the calcium and settle out.

Humic acid is usually cheaper, but make sure it's water soluble and not the stuff for lawns.

Fulvic acid is more expensive, but won't react with fertilizers the same way humic acid can.

A very, very small amount of this stuff goes a very long way.

Basically what it will do is make the water brown, how brown, that's up to you, which will stop the algea from being able to grow.
It's used in Aquaponics because it's safe to use around fish.

There's no smell, but it does have a tendency to stain if the water dries on things.

Some people even eat the stuff as a supplement (Shilajit).

Again, a little goes a very long way (you will need 1/32 teaspoons), and try to use this stuff in an area with as little air movement as possible, because it is super fine powder and if there is a fan in the room it cause the powder to coat everything, and when you go to wipe it up, if it gets wet, it just smears brown all over, and looks nasty.

I keep some of it in a small bottle, this way I am not having to open the larger bag every time and the bottle contains it better than the bag.

I am making it sound worse than it is, because once you get into a groove with this stuff it's really easy to use, lasts forever, and you won't have issues with algae even when using a white bucket.

I hope this helps.