Pinesol?

When I picked up my used 3124KS the guy who showed me how everything worked told me what he said was one of the best kept secrets. He said if you did not want to have odor problems, get 2 pints of pinesol. He said pour one down the toilet and the other down the shower drain. He said to then fill the tanks full or in our case the gray water tank and the toilet. Let them set that way for three or four days and then dump them. He said to do it twice a year. Right before storing for the winter and halfway through the camping season. He said provided you used the corrrect chemicals and toilet paper in the black water or in our case the toilet, that you would never have an odor problem and you would never have problems with your gauges. My question, does anyone know why that would be a bad idea? Has anybody tried it and if so, does it work? Oh and he said you do not need the expensive RV toilet paper. Just make sure the paper you buy says it is biodegradable. Is this a true statement or not?

Thanks in advance , Doug