Whats it like to pull about when full?
I've had a go with 'cheap' pumps before (john hewits), they where good to be honest but didnt last long (I think it was due to the strain it was under pushing through 100metres and 25ft up, but if you're not putting loads of hose on it'll be fine)
I guess if its a work in progress though and the concept works you can change as you see fit in the future...
Thumbs up matey!!