I did not see anyone mentioning using the 2 part foaming drain cleaner. I have found that the foaming cleaner helps to get the total surface of the drain line coated and help remove the soap/grease/alge/???? build up followed by a good flushing afterward. The foaming cleaners seem to work bettern on a "slow" drain and not on a stopped up drain where you need to use a "gel" type that will sink and flow to the point of blockage. The plunger only works on stoppage between the drain opening and the vent pipe since you only then push liquid up the vent.