Speaking as someone who has set up multiple skimmerless tanks, with sizes from 1 gallon up to 125 gallons, I can offer a bit of advice:
1) Deep sand bed. Not an option. Fine grained sand. Add lots of live sand too, you can afford to put in more (percentage wise) because it's a smaller tank.
2) All live rock. No dead stuff. It's hard to populate dead rock in a nano.
3) Surface agitation. I can't possibly say this loud enough. If a film develops on the surface, you are done for. What I use on tiny tanks rather than a PH, is a hang on the back filter for freshwater tanks, with the filter media ripped out. Modify the intake with a U tube to skim from the surface, and you will have plenty of laminar flow, and good gas exchange.
4) On mini-tanks, be dreadfully careful dosing anything. An extra drop is a serious margin of error on a tank that small.
5) Add sand critters, and let the population build up before adding any pred
ators. (corals count as predators)
6) Don't sweat the water changes. Watch the animals, and the tests. Thats what matters. if the animals look unhappy one day, test, and change water if necc. A large water change can shock your animals.