NSW (natural sea water) is 1.025-1.027. Some fish only people keep it lower since some diseases cant live in lower salinity due to osmotic shock, but others say fish do even better at higher salinity levels since that was what they evolved in. I think people should always try to have all levels at or near NSW levels, even if it isnt needed
What would be a recommended clean up crew for my 10g? And when should I purchase my clean up crew? I have had the aquarium running for about 4-days now.
you should purchase your clean-up crew after your cycle is over and when you have a significant amount of algae. Start off by maybe getting 2-3 astraea snails, 2-3 hermits (at your own risk) 2-3 cerith snails and call it a day. If you still have algae get a few more of each. When you get fish and your sandbed is starting to become a little mature, you can add maybe 2 nassarius snails.