No offence taken, my son as just used for approx 4 years using 2 x 25l drums the equivalent of a 50l pure freedom trolley pumping thru 100m of microbore and 25m pole hose (we are tubless) before then that £7 pump started to make noises.With respect you're adding dirt cheap non reliable components.
Why not support a British based company selling tried and tested equipment such as Darren at DA Components and for a few quid more get the chemical rated viton pump
I highly recommend if you want a temporary cheap reliable highly used pump my son was only going to work with me temporarily. Lol still with me 5 years later lol.
Yes I do support British business spent manny many many thousands £££ notes on window cleaning gear with them replacing like for like pump in a backpack made of CHinese components is normal if you ask me.
all these people that make their own backpacks/trolleys where do their buy components of the likes of Ali express then sell on eBay at a much higher profit level as they are in business just like my self ?