help on aquarium setup???

Heater = Yes
Powerhead = Yes - Increases flow in tank eliminates dead spots or atleasts assists. This keeps down problems such as cyano or nitrates. It also helps put oxygen in the water through surface break.
RO/DI = No but you will be sorry with the additional algae that is going to grow.
Refractometer = Yes. You can buy a cheap hydrometer, but if you stay in the hobby you will eventually want a refractometer for accurate SG reads.
Protein Skimmer = Yes if you got the standard Biocube, I would remove the bioballs and use the CPR unit that fits in chamber 2. If you purchased the HQI unit, I would try chaeto and see how it works, adding the protein skimmer if needed.

You need to remember that smaller tanks are very hard to keep healthy compared to larger tanks. If you are not diligent about maintenance you will encounters issues faster then someone with a 75+ tank IMO.

I would buy the better biocube now because even if you only want fish and LR for the moment you may change your mind. A refuge is going to benefit you regardless if the tank is FOWLR or Reef. The lighting alone not to mention the refuge is worth a lot more then $100.00. Last time I checked with Oceanic you cannot buy the canopy by itself so it is better to get the superior version of the biocube.

I cannot tell you how much money I have wasted due to trying to undercut my budget and then paying the cost retrofitting later. Your choice.....

 

yes, you'll need your substrate, live rock, and id recommend getting a skimmer. id get a heater as well and start there. the most important thing you'll need are test kits. and i dont recommend using the 'test-strips'. id get the reagent based liquid test kits. API, Salifert, Elos are just a couple manufacturers i can think of off the top of my head.

you'll want Ammonia, Nitrite, Nitrate, PH, and you'll want a way to test salinity to start with. for salinity a refractometer, in my opinion, works best. you can get a swing-arm style hydrometer if you want for cheaper. later down the road if you go corals you'll need to start testing calcium and magnesium too.

later down the road when you get sick of buying water and lugging it around you'll probably look into your own reverse-osmosis (RO) unit as Kelley11 mentioned.

if you got the HQI model with the fuge then you'll want to put some macro-algae such as chaeto in there. you can read about macro algaes here and you can also check out clean up crews there ReefCleaners.org | Clean Up Crews and Macro Algae - Home

good luck with your new system and welcome to reef keeping!

 

I was probably dumb by not gettng the HQI. I ordered the regular Biocube 29g. Also purchased a biocube protein skimmer, biocube circulation pump, liquid test kit, live rock, and live sand. Also what heater do you recommend? And do the protein skimmer and heater go in the back filter area? I am get excited and can't wait to get this stuff and set it up. Am i missing anything else?

 

Biocube 29 HQI includes protein skimmer

Another advantage of the HQI version of the Biocube 29 is that it includes a protein skimmer. Nice all-in-one kit.

Oceanic Systems | Products | BioCube HQI