I like having additional method to check water quality. Cory's video alerted me to this need.
Honestly I have had fish for a many years and until recently never knew you should test for phosphates. I've been having an algae issue and after watching one of Corey's videos he talked about phosphates... guess what I have a lot of phosphate right from the tap water. So I also purchased the phosphate media in hopes it will help my slight algea issue.
API's liquid test kits are always good. Price here was better than my local fish store. Yay.