Yup, the just dissolve in the substrates into te nutrients the plants roots suck up

I add new tabs in my substrate about every month, at least that's how my brand directs it. I too have a question someone on here may can answer-sorry if I hijack this thread, I thought it would be the right place to ask- I use
AquariumPlants.com 's total, phosphate, and iron root tabs monthly or as needed. I heard that osmocote plus is a GREAT root tab, so I bought some. Do I just add these along with my other tabs as I did, or what? How far apart should I space them out, how many, etc? Anyone have tips?