Dunedin Cast Iron Sewer Inspection

This sewer video was performed in Dunedin for a customer who did have a back-up prior to visit and when I ran our camera from her cleanout we've found around 43ft there was some type of blockage we could not see. Suggested for her to hire a plumber to come out to "snake" out her lines so we could come back to inspect what could cause this to happen. The sewer line under the house and out to the city tap is cast iron and we did find a problem around that 43 ft mark. Problem looks to be some kind of sludge build up and suggested to use Scotts 1000 1x to see if that helps with this situation before trying to spot repair this section.