I am trying to replace the valves to my system,,,all of the valves handles have broken off, plastic got week after 4 year of sun, rain...etc. Now I have to replace them and after calling to get an estimate, they want 900.00 to get those 5 valves and the digital timer, which I have found online for 150.00.....Can anyone give me some hints...it doesnt look that difficult to do