Converting FW to SW - Fish Only for Dog Faced Puffer

[newtopuffers]

Let me just start by how beneficial this forum has been for me, awesome website/forum for sure.

Alright, so here's the deal.
I have a 78G tank that I was trying to trade down to house a Congo puffer, but that doesn't need to happen anymore
because I just got the 30G for really cheap on craigslist, which is cycling at the moment.

Since I can still keep it, I'd like to convert this 78G into a saltwater tank to house a dogfaced puffer. Fish only.
I will eventually upgrade it to a 120G in a year or so.

It's going to be my first time fumbling with a saltwater tank, but I think I'm up for the challenge.
I've been doing some research, but I was unable to find the most appropriate way to keep a dogfaced, so many questions..
but here's what I've got so far.

1. Are protein skimmers necessary for a fish only tank if I was just keeping the dogfaced puffer? Or would a canister filter do?
2. What kind of substrate should I go with? Live sand?
3. Should I get a powerhead to 'encourage' more activity?
4. I know it can vary greatly, but under what light do you think the dog faced puffer look the best? I currently have regular single florescent bulb shop lights.

Any help is appreciated as always.

[LilGreenPuffer]

You would want a skimmer to save money. Skimmer --> less water changes --> less salt --> less money.

You can use whatever kind of substrate you want, really. Just don't waste money on prepackaged live sand. The bacteria in it dies withing a day or two.

[newtopuffers]

Hmm. yeah I know that having a skimmer is probably the best for the little guy.

My problem is that I have a cat who is rather curious.
He's always staring at my african fat tailed gecko, sometimes even sleeps on top of the critter cage.
Also at times I see random cat hair floating around my african cichlid tank. Lol.
I just want to be able to put the tank up against the wall as closest as possible, so that my cat can't get in through the back of the canopy.
Is this possible when using a protein skimmer?

[Pufferpunk]

You could put your skimmer into a sump. You'll also need live rock for filtration. I would use sand for substrate. Look into a local reef club near you.

[Dadof4]

I'd definitely go for an in sump skimmer, helps make it cat proof. Most skimmers on the market are designed to be run either in or out of the sump.