Its funny; I've been around aquariums for quite a while now and done all kinds of research for planted tanks....only recently have I read about substrate heating lol...prob wasnt reading the right things I guess. Anyway, Ive got a 55 gal planted with no substrate heater and everything seems just fine!
the few times I ran across people talking about them, they would pretty much swear by it. with the exception of a couple who said roots tangled in them, lol. others say they are useless. Im just questioning any science behind it