Hi, thanks for the feedback.
The substrate is JBL AquaBasis Plus.
As for the heated cable... My original school of planted aquarium was the Aquaponics system by Hobby Fish. Although it's been a while since I've had a planted tank, my last one used the cable and it was a success. Therefore, given the upheaval of trial and error, I thought I'd just put it in. It's very low heat, the idea being that it creates a small current through the gravel, keeping it "sweet" and helping the nutrient exchange.