Its 160 gallon, I'd say moderately stocked. I have the redsea 600 skimmer at the min have had it for the past 2 years now but last few months it hasn't been performing too well to many micro bubbles for my liking aswell even after a good clean so I'm looking for something better. Maybe something a bit more compact and low maintenance preferably with a drain. What are good options around the 500 mark?