Need advice for my tank

[yo yo oreo]

Hey everyone! A little background info - I started a 29g saltwater tank about 10 months ago, but the wife and I ended up buying a house just a couple months after I had started the tank. I never bought fish for it, I was letting it cycle in that time. I had sand, dry rock and a single live rock from my LFS and "ghost fed" the tank to get it to cycle. When we moved in May, I had stored all the rocks in buckets of water and somehow they got lost for a bit. I found the buckets almost a month later and I assumed everything would be dead (no oxygen in those closed buckets) and would have to recycle again. So I set up the tank and started to ghost feed again. I had bristleworms before the move, I assume hitchhikers from the live rock, and they surprised me and were still alive in the new tank.
Fast forward to now - My tank has bristle worms, amphipods, tiny feather dusters on the wall and something that I *think* is a Pseudocorynactis. I haven't bought anything still; I have no idea how these things lived through that experience but here we are I guess. My goal is to get a couple clownfish and some anemone. When I first started I wanted to get a bunch of fish but it turns out the fish I had wanted, besides the clownfish, need a bigger tank (I had thought about pufferfish or tangs, stuff like that) so I started looking at some anemone that would work for me. I have been taking care of the tank to get it ready but now I need some advice about what to work on next.

My tank is at a steady 0 for ammonia and nitrite and I have not done a water change in a while, over a month, and my nitrates are at 20ppm currently. I'll do a water change today and test it again later. Ph is about 8 and the temp in the tank has been around 70f. The specific gravity is at 1.023 and never goes up more than .002. I have, I think, a T8 light in the current fixture and I know I want to upgrade that. It's just a light for fish and wouldn't be good for anemone, that I am certain of. I was dropping a little food in the tank for the worms (I think they are pretty neat) and then the amphipods started going crazy. I do have some rock and would like to get a little more actually. I have a power head for circulation and a filter that helps put some oxygen in the water and add to the circulation. My LFS have a beautiful salt tank they display and don't sell anything out of that has been there for many years (15+ years, it was there when I was a child) and they recommended this type of filter to me. I was thinking of getting this kind of light here but wanted some opinions.

I was hoping to finish getting the tank ready for anemone and put some BTA in there before the clownfish, but should I go the other way? Put the fish in there first and then the anemone later? I am really excited to get the tank going and am hoping you all can help me! Here is a picture of the tank now. I have no issues hanging a light from the ceiling, once I get a better light the whole top of this tank will come off. It's just on for the current light right now. Thanks everyone!

[yo yo oreo]

I guess the picture didn't work before, so maybe this will work. It's a crappy cell phone pic but I don't own a camera at all lol. There is also a picture of the Pseudocorynactis in question. Sorry if the pictures appear really big at all!