I have an RBTA hosting a pair of clown on IM 20 gallon AIO. I have it since the beginning of 2020. I don’t dose. I test my water every two weeks and manual dose on rare occasion only if necessary. Water change every two weeks or three weeks.
I think it’s all comes to personal preference. Just for my personal experience I like my trident. I’m pretty we have members here that have a lot of positive experience with kH guardian pro. Good luck.
I always order on BRS pretty much at least once a month over $39 so it’s free shipping. I always get mine earlier that expected delivery. Sorry to hear your bad experience with them.