O just changed the substrate in my 55g and I have heard that it is inert, is it no,better than regular acrylic gravel? I will be dosing PPS Pro, and using root tabs.
acrylic gravel? I guess you're talking about the painted stone that they sell in the big chain stores?
Eco Complete is certainly a better alternative to that. Gravel has zero ability to retain nutrients; whereas eco complete, being ground up lava stone, is capable of, what's called, cec, or cation exchange capacity.
meaning, eco is capable of retaining an amount of nutrients that plants are capable of feeding off of. But, eco itself is inert and does not contain those nutrients itself. through the breakdown of organic matter (poop, food, plant material, etc), to you supplying the tank with fertilizers, eco will "store" some of the nutrients.
so no, you didn't make any mistakes switching from gravel to eco complete. others will comment that other substrates are better, or worse, or that eco is terrible/great. but at the end of the day, it's better than gravel.