Mission 1 - Pool Overflow & Filter System

Syphon Overflow

One of problems with a 'drop the liner' in type pool is getting water in and out of the pool for filtration and heating. My plan for the filter side is to use a syphon overflow into a catch tank then pump from there into a filter. I am planning to reuse the old tomato greenhouse water butt for this purpose.

The overflow will act as a kind of pool skimmer and hopefully take all the larger floating debris out. If it bungs up too quickly I will look to have a bigger filter after the overflow.

Decided to use 40mm waste pipe & compression fittings for system - cheap and easy. Flow rate should work OK for the filter pump I have bought (submerged type that will sit in the overflow sump tank).

Syphon Overflow Schematic

Filter Bed

I could use an off-the-shelf filter but that seems rather lame and easy. So my idea is to use a blue plastic barrel that happened to blow past my works front door one windy day and get stuck in the hedge. No one claimed it for a day so it got redirected into my "purposeless stuff behind the shed waiting for a purpose" heap.

So thinking along the lines of rocks, gravel, sand then gravity overflow back into pool. Need a method of backwashing the filter to clear out the clag. Could I just gravity backwash with tap or rainwater?

Think I will be experimenting for a while as I have no real pond/pool filter experience. So I am expecting a couple of iterations.

Update: June/July 2014

I had several attempts to get a homemade filter bed working. I could get the siphon working fine but the filter bed proved a bridge too far for the time being. The final straw was me pumping a whole load of fine red sand into the pool. Thankfully I drained the pool down soon after so could clear up the mess.

I have ended up using an off-the-shelf pool filter (ebay) with a submersible pump slung over the side. I run this over night and pull it out before using the pool. Not ideal as its a 230V mains pump - but the kids have been well warned to ensure its off and out before jumping in.

Whenever the pump and/or filter packs in I will look at a different solution.