Algae in the tanks, best way to get rid of it quick?

Asphaltene and 'algae' aren't the same problem.

The biocides work for microbials, all contain borax, were considered expensive by some.

It often developed in storage tanks with water not being drained, the microbes grew right where the fuel and water line was, and if you picked up fuel with it, it was bad news, bad because of filter plugging, and the microbes contained molecular water, enough the make a misfire or mess up an injector.

I picked up a batch at a preferred fuel stop and didn't make it 30 miles, then fought it the rest of the winter, we had 2 trucks in the fleet that both had it, but the people that owned the company wouldn't treat it, too costly,they said and the dealer confirmed the problem by connecting an outside tank with clean fuel which cleared up the misfiring.

Both early ISX, both had very hot fuel returns, and were idled as company policy when temps were below 20 degrees. It cleared up in the one I was driving when the weather got warm, and I helped it by drawing the tanks down pretty far before refilling with fresh fuel.

I quit getting fuel at that preferred stop, too.

Asphaltene is a breakdown of fuel caused by too much idling and return fuel, the particles bond together producing plugs of goo, it's not slimy like the microbes, but it tends to plug passages other than filters, that was a ddecIV 12.7 Detroit also idled per company policy.

Completely drain the tanks and steam clean is one way, I heard from an older mechanic that rinsing with gasoline would work. There is a bad bacteria called pseudomonas that lives similar to the diesel algae in gasoline.

I'd use the biocides, and carry extra fuel filters, drain water separators often, etc. If it was mine. Haven't had anymore problems with it in about 10 years, 2009 or thereabouts, no more trouble with asphaltene, either.