Beginner questions, please help

[Caden]

I plan on making my first reef tank, but I don't plan on making a big tank, for mainly cost reasons, and for the reason that I would only like a few small fish and a few small inverts, with 6 mushroom coral frags and 6 zoanthid frags (I love zoanthids from the pictures!).

I have several conflicts, and I am requiring some help to push my mind which way I want to go.

1. Size

At first I was thinking a 20-30 gallon cube shaped tank, but now, I am really liking how 40 gallon breeder tanks are turning out. I chose 20-30 for a nano-ish tank that wouldn't break the bank, could a 40 B run on the same equipment as a 20-30 cube (I know lights will need to be longer, which may add some expenses).

2. Lighting

How much lighting will I need to keep my softies healthy? I am not sure I want to spend 200+ on lighting.

3. Cleaner selection

For the invert selection, I plan on having a handful of hermits (still deciding on species), a few snails (still deciding on species), a yellow sea cucumber, a coral banded shrimp (or could a pistol shrimp hurt my yellow headed jawfish?) and some sort of crab. The crab is what I am having the most problem with. I want something thats not a hermit, but that won't hurt any of the above inverts or firefish gobies, jawfish, or ocellaris clowns. How would emerald mithrax crabs be? I was thinking sally lightfoot crabs could get too big.

4. Sump

I want to use my skimmer to pump the water back up to the tank, could this work? If so, can the water pass through a live rock and macroalgae section before the skimmer, or would this cause problems?

Thanks

[TheMcs]

1. A 40B will be a better tank in the long run, but will cost more to set up. An all-in-one nano with get you in cheaper but they are harder to maintain. Plus I prefer the space of the 40B. With some modification to the nano you can run it off the same sump as the 40.

2. PCs will keep your softies just fine. Most of the nano kits include PCs. If you go with a 40 you ought to be able to find a used 3' fixture pretty easily.

3. A yellow cuke won't do much other than filter the water for particulate matter, nothing that will affect your tank. Emerald crab is okay. I'm not a fan of coral banded shrimp, they can get aggressive. I'd go with a peppermint or fire.

4. A skimmer won't pump water back into the tank unless you choose HOB. Then you don't have a sump. I'm not up to speed on all the nano kit upgrades people have done & the only kit I know of that includes a skimmer is the Red Sea. If you use a sump, you can have a refugium (LR & macro area) before the skimmer.