I hadn't come across that, and I did a healthy amount of searching about that curling. Thanks!
I guess I should break these tabs in half then? Or put them farther away from the roots? I only put the substrate tabs in after I've done a 50% water change and vacuumed the gravel, approx monthly. I don't do water column fertz at all - the Total and Trace tabs is where it starts and stops for me.