Questions - Need some input

I am building a frag tank out of 1/4" acrylic, the dimensions will be 14"x14"x6". The frag tank will sit on top of my sump and the light that is shining into the frag tank will shine through the tank into the refugium. My question is what size pump should I use for pumping water up from the sump? Also what is the ideal spot to put the output and over flow for maximum flow?

here is a picture of my plan

A couple of weeks ago I found these in my sump I have no idea what they are does anyone else?

I do not know if these are the same thing but the one that is bunched up is about the size of a nickel and they are spread throughout the sump walls and baffles.

I also have a ton of copepods

Here are some other pictures of my tank recently.

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I have been holding off on getting corals because I want an anemone to find a spot so it doesn't kill any coral. I have two clarkii clown fish and the female is probably 4-5 inches long. That means that I am going to need a big anemone, the only problem is I don't have money for a big one. I don't mind much on what kind of anemone I get as long as it is not brown and has a bright color. I was thinking about buying a small anemone and growing it out in my refugium. My refugium only has sand, rock, ...