If you feel successful, you're not doing it right
, or you haven't been doing it long enough. Every reefer has times they feel like they are failing or 'if I just had this piece of gear', etc.
I can assure you that adding a sump won't fix anything. A reef tank is deceptively simple. All it needs is some substrate or rock for biological filtration, saltwater, light, and flow. Most of the gear we add is to handle higher bio-loads, or provide clearer water, or make our life easier but they aren't magic. In many ways they make it harder to succeed because you have more 'things' that can cause problems or worse hide problems.
I've been doing this for almost 50 years and I make mistakes all of the time, and I fail, a lot, I lose corals and I buy junk I don't need but I know I'm a pretty good reefer.
Hang in there from what I've seen of your tank you are doing very well. Don't forget that many of the tanks you see on here spend more money in a week on their tank than you spend in a year. How many tanks quietly replace dead corals or keep adding corals 15 or 20 at a time. We cannot all afford that, I know I can't.
