Hello, I'M new to the forum but have been in the hobby for some time before quitting and coming back. I started a 20g IM nuvo over a year ago and have been battling with Brown Diatom Hair Algae. When I set up the tank I had (and still have) a skimmer, bio-pellet reactor, cheatomorpha carbon and GFO. I also used live sand (possible issue), man-made dry rock and bacteria additives to get things started. I allowed the tank to cycle by dosing ammonia and let all my levels do the normal MEGASPIKE as I like to call it, and everything came back down to nearly undetectable levels. It's stayed there since; even after adding three fish, a shrimp, 4 snails and some corals. I had the regular algae blooms as well and they all went away before I added livestock. For some reason my brown diatom algae is making a comeback and I don't know what to do. I recently added CO2 scrubber media because my PH was high and I noticed ever since then my diatoms are going white. It looks like die off but strangely the diatom is spreading more. What should I do?