I received the latest copy of the AGA magazine today, with an article by Amano about re-setting up a tank. He describes a tank with a nice rock based aquascape, which has become overgrown with the carpet plants. His fix is to remove all of the plants, drain out the water, and replace all of the ADA Aquasoil substrate.
All of this after only about one year. He makes it very clear that he did the substrate replacement because he felt the old substrate would not be nutrient rich enough for the new planting, of HC and hairgrass. I'm still digesting that!
Then the question I guess is why even bother? A layer of peat or mineralized clay under a fine gravel would last longer, and after a year sufficient mulm would build up anyway. Seems like a ton of money to spend on something with a very limited shelf life. Although seems it makes sense, if you rely on the substrate and lightly dose the water column, eventually you will deplete the substrate. Hmmm seems like someone here has been trumpeting that horn for awhile.
There seem to be two different types of setups. 1. Setups meant for a very short time. Great for those who have the time to tinker, or creating a short term show piece. 2. Long term setups wheremay have the time to trim and replant, but do not want to do a full scale redo of the tank every year or just have less time or desire to experiment. In my case that is laziness and a tendency to stick with what works. Aquasoil probably not best for #2.