Yes, the 40 lb was barely enough. 5' x 16", and the substrate would be barely 2" if it was flat.
Tank is quite clear, now.
Ammonia is disappearing, but I think it is the plants. No nitrite yet. Nitrate is about consistent with the fertilizer dosing, or maybe a bit higher. I have not added much in the way of nitrifying bacteria. Just what was on the plants. The plants came out of tanks with very small bio load, so very few bacteria came with them.
KH is still as high as the tap water that I filled the tank with.