You can pick up some 6 in one test strip for around 10 bucks and the ammonia strip for around the same phosphate kits are around 12 bucks but you can normally take your water to any pet store and they will test it for free or some places charge a very small fee. Aqua plus is fine but I use. Prime it treats 50 gals per 5 ml vs 10 gals per 5 ml with the aqua plus. As for fertilizer I use flourish by seachem. For plants I would go with ones already grown loose plants are norm 1.99-2.99 each do research before you get the plant to make sure it's really a aquatic plant some stores try to pass off regular plants as aquatic. Java moss is the only moss I know of for a tank. In that small of a tank it wouldn't hurt to do twice weekly water changes but at least weekly. As for bulbs do you have t5 t8 or incandescent?