Welcome to world of reefing. 1) No point getting a chiller, take space and cost electricity. 10G tank use a 4 heads fan is enough liao. Unless u planning for future upgrade or having sensitive coral. Just get a auto top up to solve the evaporation issue. 2) Yes, is gd to use. U can also consider purigen is u want to be more cost saving as it can recharge. 3) if u got the budget, u can look at the bubble magus small skimmer. About 90 to 100. 4) If u want SPS then MP10 will be gd else don't need.