I OWN A TREE SERVICE ALSO WHEN I SET UP ROOFS I DO 4 TO 5 IN A DAY I MIX 55 GAL 12% 3 GAL ALCHOHOL 3 BIG BOTTLES OFF DAWN, IN A 200 GAL TANK. MY COST IS PER BATCH $160 MY GROUND GUY I PAY HIS TREE RATE $150 BUT IM DOING 5 ROOFS ADVERADGE GROSS AROUND $1500-$1800 AND NO TSP. BUT I DO HAVE 5 CARBOYS ON HAND JUST IN CASE SO AD ANOTHER $60 and it does take around 10 hrs.
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PRISTINE ROOF CLEANING ATCO NEW JERSEY NON PRESSURE ROOF CLEANING SERVING ALL OF NJ,DE & PA 856-753-7576