Cleaning Black water tank

I used to just flush mine real good with water and fill it with fresh water and empty it a few times. All was fine until last year when I flush the toilet and the items in the toilet did not go down. What had happened is over the years a pile of TP and whatever else had built up in the tank and eventually clogged the toilet. I went to the local RV store and found a chemical that was made just for this very problem. Once I used a plunger to get the toilet to clear I dumped in the chemical and added more fresh water and drove it around to slosh it around. Then per the instructions I let it sit for a couple of weeks and then flushed it out. I have a clear fitting at my drain pipe and it sure looked like a lot of stuff came out. It took it about 8 years to get to that point, so now once I year I'll just use the same chemical and go through the same process and make sure it doesn't build up again like that.