My 20 gallon nano tank

Here's a pic of my 20 gallon high tank. The pic came out a little yellowish. It looks a lot better in real life. It's been 21 1/2 weeks since I set it up. I'm using the hood from a 2 1/2 gallon tank, so the light isn't very bright. I had its original bulb in it for the first two months and wasn't getting any algae growth at all. Then I changed the bulb out and put a 13W "house" bulb in it. That's when the diatoms started growing. I just recently got a Turbo snail so all that alage has been in the tank all this time. There has been no new coralline algae growth. Just what was already on the rocks. I plan on getting another 10 pounds of live rock soon. The 2 Chrysiptera cyaneas were purchased 2 weeks ago, I added 2 blue-legged and 1 red-legged hermit crabs at 2 months, and added a Peppermint shrimp a week ago with the Turbo snail. I need to clean the inside of the front glass...



The Turbo snail's been making it rain poop. I didn't know they pooped so much, but I've been taking most of it out with a turkey baster. Oh, There's about 20-something very small snails that came in some of the live rock and, I think, 4 tiny brittle stars. I also found what I believe is a Eunice worm a couple of nights ago that's about an inch long and stringy. It's translucent with a black head. I had a larger one 5 weeks into it, but it has disappeared.

 

Good looking start.

 

I welcome all advice or critisism. I know the tank is probably too small for all the damsels, but I wanted to get a male and at least a couple of females, so it would be like in the wild. I put in 2 females and I got a juvenile, which I want to keep, but I may take it back if it's not a male. I don't have a protien skimmer - I want to build my own, but I do 10 - 20% water changes a week and uh reverse turkey baste whatever I can. Nothing has died (inverts), so I'm guessing everything is alright...?