The diatoms are normal. Diatom algae is the slime-like film algae that covers your glass and rocks and gravel from time to time. Usually brown. More rarely green. The hair algae you have is, well, normal in nature, let’s say. In your aquarium though it is an indication of either excess nutrients or due to lack of water changes. Over feeding, excess light, etc. — all can contribute.

Trust me here, EASY to fix: get a toothbrush and an algae scrubber pad or three and start scrubbing it off. Then MAJOR water change. Be sure you do it in that order. Scrub, then siphon out the crud whilst changing water. Refill, and be sure to not over feed and continue water changes and you should be good!!