22nd December 2013 at 7:55 pm #865
Some answers:
Q1 – yes perfectly possible. See the ‘Sand filter types’ part of the website where you can see what we did for plastic filters.
Q2 – it’s fine I guess. Just so long as the place where the pipe exits the barrel is watertight. Normally with rigid pipe, this is done using male- and female-threaded adaptors with rubber seals, so not sure how that works exactly with flexi hose but I’m sure there is a way. Hose should also be wide enough so that there is no siphon effect (i.e. water stops when water level reaches where hose exits container) – in my experience, 5mm hose siphons whereas 20mm hose does not.
Q3 – function is partly to stop pipe clogging, but more to increase water velocity as it exits the sand, otherwise water flows too slowly. Similar principle to why borehole drillers put coarser material around the intake screen, so as to increase flow rates into the borehole.
Would put holes on underside of hose myself just to reduce any clogging in case.