From what you already know, your choices are: take any described route or read much more, without any preconceived ideas about how it should be, taking it as how it actually is. Getting even more conflicting information, because each tank is different and each reefer has own way of doing things.
There are specialized nano reef forums, you can see what is usually done for this tank volume and even Fluvial SEA EVO.
Amount of water changes is your least concern, it can vary widely, for this tank 20-33% weekly would be fairly common, unless you start shoveling food there without removing leftovers. The same as with FW, for the same reasons, with the same outcome. You will see from the state of the tank if it needs more or less.
And from testing and corals reaction if you need to use
low or high alkalinity salt mix. I would advise on starting with low alkalinity. High alkalinity is more for big tanks with small water changes.
Start with deciding on setup modifications (filtration, flow, samd or bare bottom), then set and start cycling tank, all as in FW. If you have an access to a live rock and it is not cured yet, do curing outside the tank, to remove dead matter without killing by ammonia what is not dead yet. Read about curing live rock.
After cycling is finished, start building biodiversity by feeding tank and adding sources of variety of live organisms. Live phyto, clump of chaeto with a lot of goodies in it, from healthy tank in LFS or classifieds, maybe even some small bottled pods.
Phytoplankton is a beginning of a food chain, to feed microorganisms, to make sterile water vive water. If I remember right, AlgaeBarn should have some articles about this. Live phyto is better than preserved or dried, at least at the beginning, if you can afford it. Pods, depends on kind of pods, can eat algae on walls, detritus and even fish or coral food, copepods are large enough, comparable with keeping scuds in FW tank. The have to have hiding places, as FW scuds, in the rock or add macroalgae for a time being, but it will consume nitrates and phosphates.
Phytoplankton is plants, you have to keep nitrates and phosphates in detectable (at Salifert tests) range for both plants and corals. In the beginning, you can either: a) take time feeding tank to allow them to build in a natural way or b) dose them as I do. See Reef Chemistry section for options. I am using Brightwell NeoPhos and NeoNitro, it could be Seachem Flourish Nitrogen and Phosphorus (fertilizers for FW tank, no problems with majority of corals) or bulk chemicals, available not in all countries.
When doing any dosing, you have to monitor tank consumption rate, and add as much as it consumes, not too little and not too much.
As long as tank is cycled, detectable nitrates and phosphates are present, available biodiversity is added and fed (start with low amount of feeding, as one drop of live phyto, increasing later after tank will be able to process it), candycane frag (and any other LPS frags, not all in the same time) can be added. Feed them, target feeding either LPS pellets or frozen mysis shrimp, small kind as Hikari, not Piscine Energetics. Twice a week should be enough, once a week is bearable. Remove uneaten and regurgitated food. Small amount that is not removable can be picked up by hermits and copepods.
Reconsider your plans about cleanup crew (CUC), nassarius snails are carnivores:
- One scarlet hermit after thank will be well established (9 months or so), blue legged dwarfs can be added after they have some food to eat. Keep extra shells in variety of sizes for them. If LFS doesn't have them, dollar stores or online sea shells for crafts, undyed and not flat, can be used.
- 1-2 trochus snails or maybe 5 astrea snails, or mixture of astrea and nerite snails (3+2). For nerites better to keep tank covered, this also reduces evaporation. Without cover you will have to top off tank to keep salinity in check.
