How thick should you let your HC get? I only ask as today I gave mine a major trim as it was about 1 & 1/2 inches thick and after the trim I could see some of the plant underneath going a bit brown. This resulted in some of the carpet coming away and having a gap underneath, it's now about 1/2 inch thick and I went round randomly poking my finger in it to push some of the roots back into the substrate. I'm hoping it will take, if not I'm not too worried as I can just cut it into squares and re plant but hopefully not.