If you have four settings, they should be these:

Filter... water flows from pool through pump into filter, and out the other side back into the pool (jets). Pressure gauge on filter will show you when it's getting blocked.

Backwash... water flows from pool through pump into OTHER side of filter, out through the waste port (and into your garden), taking the rubbish that's collected on the input side away. Pressure gauge on filter will show a small reading unless you forget to open the waste valve. Check the spyglass until the water runs clear.

Drain... water flows from pool through pump straight out through the waste port (and into your garden) missing the filter completely. Pressure gauge on filter should read zero.

Closed... no water flowing.

It's the drain setting you should use because it just takes all the crud out of the pool and straight down the drain without touching the filter.

ok, thats correct as per settings - so i'm wanting to use the drain setting, so are you saying i can connect the hose into the skimmer and have the system on drain? or do i need to just 'empty' the crud via the drain hole? if you're saying the first option, that would explain why i aint been doing it right.....
would i therefore keep the skimmer tap open as well as the fondo?
thanks incidently for all the help!

Why don´t you take a photo of your system and post it on here so we can see the control handle and pipework from it.

A very good idea. It'll remove any doubt about the operation of the system... Put a photo or two up and we'll have a look later!

good idea chaps, i'll get a few piccies done in the morning and post them here.

hi all, heres a pic of the pump/piping for the pool.
you'll see its pretty old, but does still work a treat (usually!)
bottom left of pic are the 2 on/off taps for the skimmer (left) and fondo (right). the silvery selector is over to the right, as described in previous post has filter, drain, backwash, closed. the pipe exiting to the right of selector is the 'to waste' pipe.
theres no point in close ups as theres nothing in way of markings or anything. as you can see all has been conveniently painted a lovely green by the previous owner. goes well with the grass i suppose......
sand changed 2 summers ago, my ony thought for the future is to remember to buy tablets which include a flocc agent (as the current ones dont).

Confusing thread but I think you have got there. Every spring clean I floc the gunge and after a few days settling hoover it up with pump set to "waste" or "drain" ie bypass the filter and suction set to skimmer, bottom drain closed, and hoover attachment on pipe connected to skimmer suction. All gunge straight down the drain, no backwashing (yet) and all you have to do is top up or let the rain top up for you.

Looks all rather high-tech if you ask me - plus both clean and dry! You will probably find your system will go on for years and years and years... I mean you've got bits of metal where the plastic is supposed to be

I think El Capitan has summed things up very well, so I don't think there is much else to add.

lol - yes, hi-tech for the 70's i reckon!!!
thanks for your help all and sundry - looks like its sunny enough to get cracking with it!