Hi, I'be currently have been running a 10g saltwater for a year an a half now so I should be able to help you out pretty well.
1st. Do you want a FOWLR
(fish only with live rock) or a reef
I recommend getting base dry rock an letting it cycle threw with the tank. Also I really recommend getting that rock period cause it will become a main source of filtration.
Next you may want to switch out the gravel to sand or bare bottom. That way any debris that get stuck an such would be a lot less. An the key to keeping a healthy saltwater is to keep nutrients in the water down.
Own the issue of water, unless your in a place where you can go buy saltwater weekly for water changes, I recommend getting a ro
filter. It's helpful to have as it automatically removes all nutrients from the water, so no phosphates or anything. Which means less algae
Next, I use a aquaclear filter on mine as its easier to rinse the media out with ro
water, NEVER tap. I'm running the 50 model on my 10g reef tank an the 20g model on my Q tank
next a reliable heater is important as well as weekly maintenance (15%-20% water changes, pulling stuff out to clean, dosing ect.)
Also a good salt mix, I ise instant ocean reef crystals as I have a reef but Regular instant ocean works too
The key is to research research research. Read anything an everything about nanos. Be extra careful with stocking, have a good liquid test kit