15 Gallon next step

[kroth0322]

I've had my 15 gallon nano set up for 5 months now. I've recently purchased a Reef Octopus HOB 1000 skimmer. I also have a HOB filter with ceramic cylinders for biological filtration. I thought the purchase of the new skimmer would eliminate the brown algae (diatoms) I have on my crushed coral substrate, but the skimmer has been running for nearly 2 weeks and the algae remains. I've been thinking of adding an Aqua Clear 70 and modifying it to a refugium with cheato to replace my filter with ceramic cylinders. Any advice on the next step for my nano?.....