Help with Algea in older model Nano Cube 24 DX

[bkolfo4]

I have the Nano-Cube 24 DX and started having an Algea problem about 3 months ago.
Pictures are below. . .
Tank holds 21 gallons with the rock, I change 4-5 gallons on the 1st and 15th of the month.
I use distilled water and Instant Ocena Salt. The water claims the following process on the jug:
Steam Distillation
Carbon Filtration
Reverse Osmosis
Ultraviolet Treatment
Microfiltration
Ozonation
At each water change, I add ~1 tbsp of SeaChem Marine Buffer
Just installed new 50/50 bulbs from Nano-tuners when this started thinking maybe that was the problem. Run the lights 7 hrs per day.
I have the factory pump and a second powerhead installed. The water seems to flow good.
1 sponge filter in the back with 10 bio balls. Nothing else in the rear compartment (except heater and factory pump).
I feed frozen Spirulina Brine Shrimp. San Fransico Bay Brand. 1/4 cube a day.
Tank has a mated pair of clown fish, ~15 blue leg crabs, 5 turbo snails, 3 Nassarius snails.
I pick and siphon this algea off the sand and it is there again by the next day. . .
Anyone have any ideas??? This tank is 6 years old with no problems, and now it has gone crazy on me. Are the Nanotuner bulbs good??? I am lost. . .
Thanks!
Brian

 

[nissan577]

the red algae???? cyano

 

[speg]

That's what it looks like to me too.. better search the site for cyanobacteria....aka red slime algae.