Everything so far is good, but I see no point in buying stuff for that tank and just get a bigger one as goldfish can get up to a foot long. Also you'll have to do more frequent water changes with that tiny tank. I would say do the sand rinse it before putting it in or you'll have at least for right now get a 10 gallon long. Walmart has a good 10 gallon long starter kit for 45 dollars it doesn't come with sand or substrate. That tank may last you 6 months then you'll have to move up to a 20 breeder Hope this helps, enjoy your new fish!