the house was empty for 3 years and the washing machine drain is slow altho for a while it was working fine… i put 2 bottles of marc 55 down the drain with no success. now i want to try muratic acid and wanted to make sure it wouldnt harm the cast iron
Tex ,don’t waste your money on drain cleaners.Have the line cleaned out by mechanical means.Been plumbing for 35 years and never had much luck with chemical cleaners.All they do is cause problems for the plumber when call to clean the drain.Have it cleaned right and you should be ok,providing the line is installed correctly.