I have the same problem too. But what has been helping is getting something to raise the gh if you have well water or reverse osmosis like I do. I’ve done this and mine boy has had a lot less problems. A good gh range is 7-14 degrees. (I have know idea why they measure in degrees.) and API sells gh and oh tests kits that can be found at your pet store or on Amazon https://www.amazon.com/API-TEST-Freshwater-Aquarium-Water/dp/B003SNCHMA/ref=mp_s_a_1_3?dchild=1&keywords=gh+api&qid=1623260311&sr=8-3 And I see you’ve been putting in crushed coral so you might not need to add anything.