If you don’t mind me asking how often do you water change
Real answer, or the " I'm supposed to be an expert so obviously religiously" answer....?
Real answer is rarely, but i am rebooting this week. (See my updated build thread later this week with explanations)
In a 40 breeder, depending on your bio load, 5 gallons a week should be fine. If you don't have good skimming, AND a truckload of fish and corals in your little slice of the ocean, you should probably be doing more. But i will also tell you keep on keeping on if you are being successful.
Change, and big change being the worst, usually isn't great... Stability is key....