Thank you for the work that you did for me to fix the blocked floor drain in my basement! You are very professional and I appreciate the pride that you take in your work.
Initially when you cleared the drain that the water began to flow, you checked inside the pipes using your camera equipment(can’t believe I almost got a plumber to snake without camera equipment to check afterwards), you weren’t satisfied as the pipes still had enough sitting water that you weren’t comfortable with.
You could have packed up at this point because the water was able to flow but you continued to push the coils through as far as possible to the point where whatever residual impedance was cleared and the remaining sitting water in the pipe drained.
Thank you also for locating the exact position of the external clear out vent. You definitely came prepared with all the necessary equipment to do your job well!