Cleaning Patios as a By-product of Ponds

In my pursuit of an algae free pond, and having given up on the local plumbers' merchant and the Aquatics place for pump unions, I was advised to visit a place called Rio Pools in Charfield, and I'm glad I did. The bloke who spoke to me was ever so knowledgeable about pumps and connections. He even gave me some items to test out, along with a free tin of plastic piping cement.

While we were talking I saw some large, plastic canisters of sodium hypochlorite. I asked the chap helping me what it was for and he said it was a very strong bleach that's used in pools in very low concentrations to keep them sterilised. Having heard about the cleaning effect on patios, I quizzed him about its efficacy, which he confirmed. "Just spray it on, away from any plants, and let the next rain wash it off."

I bought 2 x 50 ltr canisters for £67. I then tested it on a few select flagstones that were particularly affected by algae and lichen.

The result?

It works a treat! As you can see, the original yellow hue of the flagstones came out almost immediately and there was no scrubbing. It's essentially a very powerful bleach, being at 15% concentration, which is double the concentration in household bleach. It decomposes on contact with organic material and sunlight into salt, water and oxygen, so pretty innocuous once it has done its job of grabbing organic molecules and disrupting them, so long as it doesn't hit plants (moss and weeds between the flags are OK).

The place smelled like a municipal swimming pool for the afternoon.

Hay noticed that extraneous spray also managed to bleach my trousers! That's a new pair of working trousers I now have.

Actually, a bit more spray and I could call them camo trousers.

It will need a couple of applications to the patio, and putting it on during a sunny spell allowed it to dry a bit too quickly; however, that avoids the cats walking through it while wet, but I'll certainly be using it on the rest of the patio as the weather permits. To ensure the cats didn't walk across it, I kept watch while it dried.

One 50 litre canister is enough for our extensive patios to the front and rear, with enough left over for use on the top car park as a weedkiller. so it goes a long way. It's also much cheaper than commercial weedkiller - and even my own homemade concoction.

Finally, after years of trying different things, I have a solution to dirty, grey flagstones.