Getting back into the hobby, nem/clown tank build setup help

[Jl330]

I got out of the hobby for a year or so but am opportunity to get back in fell in my lap.

My build will be based off a 75 gallon tank and I want to do anemones and clowns only, probably a harem of clowns if I can get a good bunch of them together. I've never done nems before other than rock flowers but I'm assuming they need to go in first.

I had a mixed reef before, I'm assuming this setup will not consume alkalinity and calcium like my hard corals did but what should I be looking into/concerned with going this route?

 

[Tuan’s Reef]

BRS did a Clown harem tank .....

 

[reefinatl]

Tagging along as I also wonder what I should be monitoring. My main reef I just check alk and dose All4Reef with good success. I don't think that'll work on my new and clown cube.

 

[Jl330]

BRS did a Clown harem tank .....

That's where I got my idea. That video is helpful.

Looks like they added the clowns first then the nems and they suggested t5 lights. I have LEDs but can add t5s later.

Will bare bottom be good for a tank like this or is sand a good idea? Are hermit crabs friendly for nems or just snails?

Lastly, how many clowns should I add in a 75 gallon if I'm only going to add clowns and no other fish? I was thinking 15.