When I got my TM last year I was interested in the liquid version of UM because I used the powder in my porty quite a bit. Last time I spoke to Chris at Alltec about the liquid product, I think he said there was some sort of issue with the formulation so they withdrew it until the issue was solved. As far as I know that hasn't been resolved yet.
Powdered version as stated is a pretty good extraction detergent, can't say whether it is very bad for pumps but no doubt you'll need to change your diaphragm a bit more often than if using just plain water. The detergent solution is slightly abrasive, so it will wear the diaphragm a little bit more than usual.
That said however, you can do two things to maximise the life of your pump:
1) Thoroughly mix the product in a bucket of water BEFORE adding to your tank. Mix it up with hot water and let it dissolve fully... it will look a milky cloudy colour whilst still dissolving - you need to let the water go clear before adding to your machine. This takes a few minutes but with good planning during set-up it shouldn't add any time to the job. Make your first task to fill 2 buckets with hot water and mix the product whilst getting the machine out of the van. I used to use a big metal spoon to stir it in the buckets which helped dissolve it quickly.
2) At the end of the day, suck out all the solution from your tank and then add some cold fresh water. Run this through the pump for a couple of minutes, to flush it out.
If you do both of those things you'll probably only shorten the life of your pump by a small amount. If you put the powder straight onto your tank and add water, and if you don't flush the pump through at the end of the day, you'll be buying a lot more pump parts!
Just my experiences, hope this helps
