The general answer to that is no. The bacteria you want live on surfaces, not in the water. The exception to that is in the initial cycle, about the first 30 days of the life of the tank, water changes would remove ammonia and nitrite that the colonies need to develop and grow.
Ive had a hammer for 15 years same colony. They are pretty hardy. My guess is your alk is the issue. Get a better test kit bc i dont think you can get a alk level that high by just doing water changes. If your going to keep lps and sps just invest in a hannah tester for alk. Its so easy, refills are reasonably priced and if your alk isnt stable your corals will strugle. Domt buy ati test kits in my opinion. I used to buy them long ago. They arent very good. I use red sea and hannah testers for most things, but there are some other good choices.
Your clearly going to get different opinions on the filtration but while i dont think its causing your peoblem i do think what your running is over kill. I dont run any chemical filtration other then carbon and gfo in a reactor and the chateo.
But how do you keep alkalinity stable?
Everyone says don’t dose unless you absolutely need to
Their my favorite that’s the reason I got into the hobby. I love the movement they give and the colors. I don’t really care for sps. I just want to master taking care of euphyllia
