Yet another drainage problem

Hm. The cut off bottom of a plastic barrel, maybe? Cheap, also if you get a build up of stuck-on muck, you can bend it. Overflow is easy, cut a hole in it and use plastic fittings.

I presume the intention is to allow the solid matter to settle out before sending the water to the drain?

I would have thought it would need to hold the slurry for a while to allow it to settle, rather than having a continous flow through it. Having a drain at a fixed place may also prove trickey since it will only work when full - but the level of solids in the tank may be much lower. Perhaps you need some form of sliding side so that you can set the level that water is drawn off?

Roadside gutters drain into big plastic barrel-like sumps to catch the leaves and suchlike before connecting to the main drains. Not sure about UK stable as they're normally buried. But an amble round a big below-ground drainage merchants might provide some inspiration.

Owain

Flexible might be helpful too for if it gets so crudded up that I want to replace it without moving the slabs. Now I've started thinking about VERY flexible, like a binbag. No maybe thats just too tinny, but something that will easily fold up to come out and is readily available to do replacements ... hm

Anna

~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

Yes

Would be lovely, but moving parts and mortar don't go together very well cos very soon the moving parts don't. Maybe I could organise a siphon to draw off the water and decant it onto my new neighbour's garden which conveniently is a couple of feet lower than mine

Anna ~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

I'm thinking of something like a super-charged cement-mixer (without the baffles inside) that instead of churning things together centrifugally separates the solids from the liquids.

Owain

Try a beach centrifuge