Hi Guys, just thought i share my experience with those starting this hobby, since i have an hour to spare. I've been in this hobby for about 5 yrs now, and still I'm making heaps of mistakes, but always learning along the way. I used to own a 3ftx2ftx2ft tank, I went from soft corals, to lps, to sps, to Fish only (went overseas to study, my dad had to take care of the tank for over a yr, no idea what he was doing except to change water). I now own a 2.5ft tank with built in overflow and sump, currently mix reef with mainly sps corals. Here are couple of mistakes I've learnt over the few years.
1. Water requirements
This is the biggest pitfall for any new reefer. Hence its my biggest mistake. Before you even decide on a tank, decide on what u wanna keep. Fish only / corals/ sps corals? Once u understand the type of fish/ corals u intend to keep, study up on water parameters. The biggest failure in this hobby is water parameters, something out of place, and your tank will most likely be overtaken by algae or even worst corals/fishes dying.
Heres my recommendation: Get a good salt mix. A good salt mix will basically determine your success right off the start. I started using cheap-po salt at the start, and corals died time n again, wasted more money buying corals. Get a reputable salt brand base on what you intend to keep. Don't just trust the salesperson when he tells you this salt mix is good and buy (my mistake again). Buying good salt mix alone isnt gonna cut it. You still need good Water to mix it with!!! Tap water is fine if u are able to export the nutrients found in tap water (which is really high, commercial liquid products for treating water is never sufficient). For small tanks, i found it most economical to just buy bottled water from NTUC and mix in your salt. For large tanks, RODI unit is definately the only way to go. You canalso buy Natural sea water, but personally i found the parameters not to my desire. Last option is you can purchase premixed saltwater from a trusted retailer.
2. Choosing your tank size. Firstly, its important to know exactly how u want your tank to appear.
Big Tank: Pros, Plenty of room for fishes and corals, Better stability of your water parameters, more room for error when your new. Cons: Prepare to get wet, and put aside time for maintainence. I.e Scrubbing algae of the tank walls, arranging your corals and rockscape, preparing water for the scheduled water change etc etc