algae in my bubble bucket

I'm trying a bubble bucket for the first time.
I started 6 clones, nearly 1-1/2 to 2 months ago now.

Originally I had them in soil. About 1 month ago, I took the clones from the soil and started the bubbler. I cleaned them up really good, although they weren't completely free from dirt, they were as clean as I could get them using my fingers and a spray bottle without damaging them too much.

Anyways, they did start to take off within the firts week or so, but then the algae showed up, possibly from light leaks. I fought it for a week or so, then I pulled all the clones, and recut them, starting over.

Entirely new bucket, no light leaks, the clones were fine for about a week, untill I started adding nutes. Algae again. I gave the clones an h202 bath, then refilled the bucket with plain water and h202 and left them in that for a few days, then changed the water. Kept the clones on plain water for a few more days. Then I started feeding and again the algae came back.

Gave them another bath, and realized that the temp was about 70 in the bucket. I turned down the thermostat in my house, to keep the room temp down a little, and we got a cold spell of weather. The bucket temps stayed aroud 65 for about 1 week, and in that time I was able to give the clones nutes, and the algae was not dominating, if growing at all, I couldn't tell.

The weather changed and the temps have risen back up to 70, and the algae is back again.

Ok, I know, these things are pretty hurtin, and 2 months for clones is crazy. I have another bucket started with a fresh crop of clones also, I haven't added nutes to them yet so they haven't had problems with algae so far.
I'm keeping the others going for experimentation, so I can try to get this bubble bucket thing down packed.

So it seems, that despite being light proof (save a few pinholes around the stem, above the hydroton), algae will grow in warm temps.

Any ideas how I can keep the temps down?
I could put a bottle of ice into the bucket. But my buckets are pretty small.

Part of the temp problem is likely to do with the size of buckets I'm using.
My buckets are 3Gal rubbermaid, with about 2 to 2.5Gal of water in them.
I'm working on setting up a reservoir system, so I can constantly circulate the water in the buckets with the much larger capacity of the reservoir.
I still don't think that will be enough, though I'm going to anyways, mainly for ph and nutrient stability.

I was considering buying an electric cooler and using that for my reservoir. I think they are waterproof.

 

Algae reguires light.

Block the light and the algae dies.
Sometimes plactic buckets will allow enough light tranference to allow algae to grow (it doesn't need much). You might want to buy some black construction paper and encircle your buckets with it.

 

There is no light.
The buckets are lightproof. I'm positive. They are covered with tinfoil.
Could it be somthing else besides algae?
The roots are definitely rotting in the water. Above the water, the roots are healthy.
I did notice while cleaning the roots yesteray that the gunk just came right off, easily.
It also looked more like rot, than algae. Before, the algae was white and fluffy and was difficult to remove, even with a spray bottle. This time it just rubbed right off, and the roots inside the gunk were relatively strong and healthy still, instead of breaking apart like mush.