Sodium Hypochlorite Patio Cleaner – 2 x 5 Litres of Industrial-Strength Algae & Black Spot Remover – Powerful Driveway & Paving Cleaner – Professional Outdoor Cleaning Solution for Concrete

This is my go-to for patio and driveway cleaning. I use it mixed with water and a surfactant in a jerry can, and it performs extremely well with my pressure washing setup. Black spots, algae, and grime come off fast, and you start seeing results in under 10 minutes. Pros: • Very strong SH mix (14–15%) that works quickly • Great value at under £18 for 10L • Ideal for concrete, tiles, and stone • Pairs perfectly with surfactant and water for pre-treatment Cons: • Strong chlorine smell (normal for SH) • Will bleach fabric and sensitive surfaces—use PPE Verdict: Excellent for exterior pressure washing pre-treatments. Results speak for themselves.

Excellent kit, I get three 10l watering cans out of a 5l container, so roughly 30% Juice to 70% water. Great for cleaning slabs and mono bloc driveways a very good option to pressure washing which erodes your brick/slabs. It also blooters weeds into oblivion. I also use a similar mix and spray my house walls as I live right next door to bonded ware houses which produce Whiskey Black, this stuff turns my nice dark brown brick a manky black colour.. simply mix and pour..

Using a chlorine solution is known as "Soft Washing". Called this because high pressure blasting isn't necessary to get an amazing visual difference in a short time. Two areas of Indian sandstone patio were looking a mess, I thought that most in the more shaded area would need to be replaced! Sandstone is soft and porous by nature, algae and lichen love the stuff. Sandstone is vulnerable to erosion, using a Karcher dirt blaster lance started to cause pitting in some of the softest areas of individual slabs and I was looking for a better way to defeat algae, Lichen etc. I knew that after a general wash down, bleach was the tool, but the domestic thin bleach is just 2% w/v of sodium hypochlorite (Hypo), which didn't work, even applied neat and left to soak. This Hypo is 15% when new, I made a solution with 50% tap water, sprayed it on the slabs and quickly noticed areas of small bubbles as organic residues were oxidised. After sufficient dwell time, it was rinsed well with a hosepipe. There was an amazing initial effect and for a few hours after rinsing, the slabs appeared to be getting cleaner still! It didn't cause any chemical staining of the sandstone and hard scrubbing was not necessary. Some of the more heavily affected areas had a slight visible residue of dead organic stuff! This will lose its grip after a few rain showers, washes and a re-treatment. Value for money lost a point because I purchased two 5L containers, a single larger container would be cheaper by unit, but it was my first trial of this specific product. Ease of use lost some points, only to highlight that it isn't something anyone can apply safely. It MUST be used and handled with great care. PPE should be used, access to areas being treated must be controled, pets must be kept away until it has been rinsed very well. There's much more to safety than these basic points, which aren't a guide. I used a backpack sprayer with an oval "drift guard" surrounding the nozzle, this stopped spray mist from being blown away from where it was being applied.

This works very well. I have a large driveway which for past few years I've given a quick whizz over with a patio attachment on my pressure washer. Unfortunately I think this just spreads the white lichen spores & black spot spores so they just come back over time, but much worse. After using this stuff, my driveway looks almost new. I did use the high pressure lance on my pressure washer, which of course forces out the sand between the block pavers. So I brushed in some 'Sika' setting sand. Took some time to do it properly, but worth the effort.

This was an absolute game changer for me. My patio was covered in black spot and was looking very tired. I tried this out got 10ltrs. Only need 5 ltrs to complete the clean. I did mix it strong and would advise a face mask as this is powerful stuff. I applied with a sprayer a slab at a time and you could see it start to fizz immediately. I coated the whole patio which is approx 25ft x 16ft and had a bit left in the spacer and I gave a little more to the more heavily stained ones. Within an hour you could see that the black spots were almost gone and it was looking like new. I did this in the evening so am gonna leave on till morning and the rinse with a hose. If you want a clean patio don’t think twice and get this. Also I have still got a 5 ltr tub full so I can dilute this weaker for a maintenance wash as apposed to a deep heavy clean. So win win for me. Very very happy.also no jetwasher was required

Great product for cleaning the patio and getting all the grime and algae removed, will also remove black spots. I used in a sprayer with 50/50 diluted in water. Wear old clothes as this is a bleach and will ruin just about anything it comes into contact with. I also recommend nitrile gloves and goggles too. Soak patio in spray leave for 30 minutes or so and rinse with hose or jet wash.

For medium soiled stone work I recommend 3l water : 1l solution For areas such as blackspot you may need to reaply after a week with a concentrated solution 1:1. Apply using a fine rose water can and it will go a long way. Avoid winds and sunny/wet days. Ideally you need to leave it down for at least 2 hrs. Rinse off with a hose pipe and away from lawns and plants. The water will reactivate the solution so you can always use a hard brush to re work into those stubborn areas. I strongly recommend using a resperiator mask, heavy duty rubber gloves and wellies/work boots. If you've got kids or pets keep them off the area for at least two days or after thoroughly rinsing the area down. Game changer!