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20L Simply Spray & Walk Away Moss & Algae Killer for Patios and Decking

£27.95 inc VAT
£23.29 exc VAT

20L Simply Spray & Walk Away Moss & Algae Killer for Patios and Decking

Over 100,000 bottles sold | 1 bottle sold every 13 minutes

2989 reviews
Was £28.99
Now £27.95 inc VAT
Was £24.16
Now £23.29 exc VAT

Order now for delivery 25th March

  • Kills Moss and Algae on hard surfaces
  • Treat patios, decking, fencing, pathways, roofs, UPVC - anywhere moss grows!
  • Super concentrated formula - 4 parts water to 1 part Simply Spray
  • Helps prevent moss and algae regrowth
  • One 5L Bottle covers 200 square metres
See more product details
  • In stock
  • Warranty: Not applicable
  • 30 day money-back guarantee
  • Product Code: 229024
  • Have a question? Call 0800 091 3171

Product information

Brand: Pro-Kleen
Weight: 21 kg

4 x 5L of Pro-Kleen Simply Spray & Walk Away Moss Killer

Also available in 5L, 10L and 20L!

Not only is moss unsightly, it can also create danger on outdoor floors with its slick and slippery surface.

Pro-Kleen Simply Spray & Walk Away easily kills, removes and prevents moss, green mould and algae on hard surfaces! It's formulated for use on patios, fencing and decking. It's even suitable for roofs, uPVC windows, boats, caravans, motor homes, sheds, decking and driveways and most outdoor surfaces where green mould, moss or algae is present.

Why choose Pro-Kleen Simply Spray & Walk Away?


We have sold over 100,000 bottles in the UK and 1 bottle is sold every 13 minutes. This just proves how amazing it really is!


A 5L bottle of Simply Spray & Walk Away makes a minimum of 25L of solution covering a HUGE 200m² area!Simply Spray & Walk Away is a maximum strength super concentrate boasting 75% more active ingredient than other brands! This solution can also be diluted to make up to 50L of solution at 1:9 dilution.


The dilution rate is 1L solution to 4L of water. A little goes a VERY long way! Apply in dry conditions avoid applying when rain is forecast within the following 8 hours summer apply late afternoon / early evening (when sunlight is less intense) The solution can be applied up to a massive dilution rate of 5L solution to 45L of water for less affected areas, which would cover a huge 400m² area. TIP: The less dilution the quicker the results.


Perfect for use on patios, decking, fencing, paths, driveways, roofs, sheds, greenhouses, garden statues, terracotta pots, UPVC windows, boats, caravans, motor homes and all indoor & outdoor hard surfaces affected by moss, mould and algae!


Once treated results will show in 2-3 days! Simply Spray & Walk Away penetrates your outdoor surfaces creating an invisible barrier which will help to prevent re-growth for up to 6 MONTHS!

100% SAFE

Biodegradable. PH8. Non-caustic, no acid & no bleach! Simply Spray & Walk Away is safe for use around children & pets once the area is dry.

How do I use it?

Read the instructions on the bottle carefully, then simply decide your required dilution and apply with watering can or pump sprayer and apply the solution to the entire area.

Why does moss appear?

Moss often appears on hard surfaces in shady and moist environments. It may be more noticeable after a wet spell or during winter but is present year-round. Moisture allows moss to grow and reproduce. Under the right conditions, it can quickly take over a patio surface. 

If you have a problem with moss on grass, then use Pro-Kleen Iron Sulphate which also greens grass and hardens turf.


Rating 4.5 out of 5 based on 2989 reviews.
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Excellent product. Easy to use
9 Mar 2019
Barry Lyne
Excellent ihave used more expensive product, this gave the same good results .in area that were heavily marked I used a 3-1 dilution
8 Mar 2019
Dave Martin
I have used many products in the past to get rid of moss and algae from a tennis court and a paved area but nothing has worked as well as this,will be buying more in the near future for other areas as it has worked really well
5 Mar 2019
Robin Ainsworth
Fantastic cleaner. Used for years professionally. Always recommend as it's also not acidy. Tried other. Thanks
5 Mar 2019
Great product, quick to act. Only four stars as don’t yet know how long it will last.
1 Mar 2019
Customer A.Ingham
Brilliant cleaner
26 Feb 2019
Paul Adams
There are a number of products like this on the market, but this is as good as any I have used and is very good value for money.
6 Feb 2019
CC and BH Hinksman
Brilliant service and product - thank you
5 Feb 2019
Robert Bowen
Fair Price for a product that was just amazing. As it said " Simply Spray & walk away" Moss & Algae killer for decking and patios. I bought it for my caravan that is stored out in the open all year in a CaSSOA storage site. My Caravan looked like it had gangrene, then as I sprayed this on it literally started to melt away running down the sides of the van. So I left it and I am due to pop back to hose it off and re-treat, and the good thing is that it stays active for a long time. So if you have a Caravan or Motor Home or just lots of moss etc this one is for you.
30 Jan 2019
Colin Clarkson
Does exactly what it says it will!
30 Jan 2019
Amazon Customers
2858 Amazon customers reviewed this product

Frequently asked questions

What is the active ingredient (chemical) in this product and what % strength is it?
The active ingredient is benzyl alkyldimethyl chloride at 1 - 10%. 
I have bought the simply spray and walk away mould and algae remover. I just wanted to check- is it suitable for use on Tarmac as it doesn't mention it on the container.
Yes it is suitable for use on tarmac.
I have bought the simply spray and walk away mould and algae remover. I just wanted to check- is it suitable for use on Tarmac as it doesn't mention it on the container.
This is suitable to be used on Tarmac.
is there a minimum temperature for application
As this is a water based product, it will freeze at low temperatures. Therefore we would recommend you to apply the product when temperatures are higher than 5 degrees. 
I need to use pro Kleenex on my roof. The water from the roof is collected in water butts. Can the water still be used to water the plants? Brian Taylor
The water collected in the water butts cannot be used to water plants.
How long will it last unopened before it ceases to work? Does it require special storage ie frost free, low temperature? Do I need to wear protective clothing when using it?
This product does not carry an expiry date and if stored with the container tightly closed, can be stored without effecting the performance for up to two years. Store in a cool dry environment but avoid from frost.
Hi, Will I be able to apply a paving sealer over the top of the moss remover - once the moss remover is dry of course? Also I'm looking spray the moss killer on an asbestos roof, which needs an acrylic water proof paint applied to it afterwards. Will I
Yes, once it is dried, you can apply a paving sealer and paint over the product.
HI I have dogs is this safe for them? What precautions should I take? When can they walk on the sprayed area?
This product is pet friendly. However, we would advise you to allow the product to dry before allowing pets in the treated area, for optimum performance.
I have plants at the side of all plants. Do I have to protect the plants when I spray the paths & Patio.Also what about fences with climbers nearby.
This product may damage any plants and climbers, so we would advise you not to use in areas where run-off is possible.
At what time of year should pro kleen be used
Ideally from Spring to Autumn. It can be used in Winter but only when there is no chance of freezing, as this is a mainly water based product.

We would advise you to make sure the surface is dry and in conditions when rain is not forecast for the next 8 hours. Apply late afternoon/early evening when the sunlight is not at its strongest.
If I make up a mixture (4L water to 1L Spray and Walk Away). If I don't use all the solution in one go how long can this mixture be stored. It will be in a pressurised garden spray?
Once the product is mixed with water we would only advise to store for two to three days.
Is this product suitable to use on boat canvas?
Yes, this product can be used on your boat canvas, but only if the boat is dry docked (on dry land). The product is harmful to aquatic life, so avoid it entering waterways.
Is it safe to use on a ashfelt roof
Yes, this can be used on an asphalt roof. However, avoid run off into water butts, plants and lawns, as the product will cause damage.
does this product contain weed killer, will it affect surrounding plants/shrubs?...
This product does not contain weed killer. However, we would not advise you to use around grass, plants and shrubs as it may damage them.
Coverage per litre
1L of the Simply Spray, when diluted with 4L water, will cover approximately 40 square metres.
How long after treating my fence with simply spray is it before I can paint it and do I need to rinse it of before applying the fence paint.
We would advise you to leave the fence for 2 weeks before applying paint. You do not need to rinse it off before applying the fence paint, just brush off any dead moss if still present.
Can it ne used on brown slates without discolouring.?Aidan
Yes, this product can be used on brown slate without discolouring.
If I have used a sealant on my Indian sandstone paving will spray and walk away still be effective or lead to any adverse effects? Thanks
This product should be suitable for your requirements.
Can it be used on Teak Garden Furniture?
Yes, this can be used on teak garden furniture.
I have moss patches throughout my artificial lawn. Is this product suitable for artificial grass lawns. Thank you
Yes, this product is suitable to remove moss from artificial grass.
can this be used on mould in a loft space
We would not recommend using this product, but we do have a very effective mould remover for indoor use. Please follow the link below to the correct product:
Does it require any scrubing after applying it or do you just spray it on, leave it then rinse it off?
Yes, you simply spray and leave it to kill the moss, mould or algae. More stubborn thicker clumps may need to be brushed away.
Can I use this on greenhouse roof? Glass panels and timber struts dividing them. Otherwise endless scrubbing required to get rid of build-up of dirt
Yes, this can be used on a greenhouse roof.
Can this product be used on rendered house walls
Yes, it can be used on rendering, but with any large surface area, we would advise you to do an inconspicuous test spot first.
Can this be used on upvc cladding?
Yes absolutely it works great on UPVC
I have large lumps of moss on the north side of my tiled roof. Can I just spray this product on and then it will all die off or do I need to scrape it first.
Yes if the moss is very thick it may need a little scraping once it turns brown and the solution using a little stronger (1:2 or neat) 
Can I buy this product in any of the big D I Y stores
Pro-Kleen is sold online only at the moment 
Hi I’m due to jet wash some mossy garden walls and patios which have plants and lawns around them. Will this product kill the plants and grass with any over spray? Is this a suitable product to use?
Yes, this product will damage grass and plants.
Can I use this on natural limestone tiles on my outside steps and patio?
Yes, this product can be used on natural limestone but we would advise you to use the correct dilution rate.
Hi I have Indian rainbow natural stone , I took the time to seal slabs properly but within 6 months of a 5 year sealant the moss and algae as covered moss of the slabs . I have paid hundreds trying to fix this but after a couple of weeks it grows back in exactly the same places. Will this be suitable to kill the moss and algae and also take the slabs back to their natural colours or will this just kill the moss and algae but leave the green tinge there? Many thanks
Simply Spray will kill the moss yes however for cleaning purposes ie getting it back to its colour, we would recommend our Patio and Drive Cleaner product that will do both jobs in one for you.
Hi I have Indian rainbow natural stone , I took the time to seal slabs properly but within 6 months of a 5 year sealant the moss and algae as covered moss of the slabs . I have paid hundreds trying to fix this but after a couple of weeks it grows back in exactly the same places. Will this be suitable to kill the moss and algae and also take the slabs back to their natural colours or will this just kill the moss and algae but leave the green tinge there? Many thanks
This product will kill moss, mould and algae only. It will not remove stains.
Hi there, I have green artificial grass next to my patio. If I spray this and leave it, any run off will be to the artificial lawn. Is it ok if this product goes on the artificial lawn? Will it cause discolouration?
It is absolutely safe on artificial grass, it can be used on there so any run off will be fine 
Is this come as a ready to use or I have to mix
This product needs to be diluted. We would recommend a dilution rate of 1 part product to 4 parts water.
I have thick moss on my pebble drive, no doubt growing on any soil between pebbles. Will your moss and algae killer work on this?
Yes it is suitable for use on a pebble drive.
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