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10L Simply Spray & Walk Away Moss & Algae Killer for Patios and Decking

£18.98 inc VAT
£15.82 exc VAT

10L Simply Spray & Walk Away Moss & Algae Killer for Patios and Decking

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

339 reviews
£18.98 inc VAT
£15.82 exc VAT

Order within 9 hrs 31 mins for delivery tomorrow

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Buy 2 pay £35.68 - save £2.28 Buy 3 pay £52.38 - save £4.56 Buy 4 pay £68.36 - save £7.56 Buy 5 pay £83.50 - save £11.40
  • 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: 229021
  • Have a question? Call 0800 091 3171

Product information

Brand: Pro-Kleen
Weight: 10 kg

2 x 5L of Pro-Kleen Simply Spray & Walk Away

Also available in 10L, 15L 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 339 reviews.
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Page 1
Did what it was supposed to.
22 May 2019
Mrs Lynda Bradley
my husband says this pproduct really works and good price
11 May 2019
That’s stuff is excellent. Little amount clean my all garden not only from algae but also all dirt that collect over a year. Love it and highly recommending
3 May 2019
Lynne Ellis
Great product,does exactly as it says on the bottle.
16 Apr 2019
Keith from Dover
Works well.
16 Apr 2019
Martin Johnson
The price was great and the product works
11 Apr 2019
John Pardoe
Great product at a good price
9 Apr 2019
Robin Eddleston
Arrived promptly and does exactly as it says. Couldn't be easier.
12 Mar 2019
Nick Fitzgerald
Works brilliant on the concrete to remove moss. 100% satisfaction.
29 Jan 2019
Nina Reeder
Great service,quick delivery,excellent product,does exactly what it says on the container,would definitely re-order in the future
13 Nov 2018
Amazon Customers
212 Amazon customers reviewed this product

Frequently asked questions

do you suggest a number of days or weeks between the first &second application ? and when the moss dies is it best to brush away or leave it ? thanks
If the area to be treated is very bad then a second application would be recommended about a week after. Otherwise, only one application is usually necessary. The enzymes in the liquid will eat away the moss, but it will give a better finish to the treated area if you brush afterwards.
Hi Can this be used on glass, as my glass conservatory roof is now covered in algae?
This product can be used on glass conservatory roof.
hi is it safe to use this product on sails ?
We would not recommend to use this product on sails.
Hi, Can this product be used on my uPVC window sills and conservatory? Many thanks Alan Ward
This product can be used on your uPVC window sills and conservatory.
Can you please tell me if this product is safe to use on sandstone (Tobermore Pietra Sahara sandstone) without damaging the colour? Thanks.
This product should not damage the colour of the sandstone. However, we would always recommend to test a small area first.
Can the product be used on a polycarbonate roof (of my conservatory)?
This product can be used on conservatories as the chemical only attacks the green mould and moss but does harm the surface.
Can Pro-Kleen be applied to wet surfaces i.e. in our current damp winter. Other products require dry conditions, which means I cannot use them for months. Thanks.
This product should be used in dry conditions, with unlikely chance of rain. 
What are the active ingredients?
The active ingredient is benzyl alkyldimethyl chloride.
Hi, I am looking to clean up some decorative gravel which has algae on it, would this remove algae from this Cotswold gravel with it being pourous? Thank you in advance. Mr Morris
Yes, this will be very effective on removing algae from Cotswold gravel if used according to the instructions.
is it harmfull to plants
Yes, it will damage plants and grass so please avoid spillage/run-off on to borders and lawned areas.
Can the fence be painted after treatment?
The fence can be painted after treatment, but we would allow 2 weeks before painting.
My delivery of Pro Kleen spray & walk away has just arrived. I am concerned that on the container label it indicates that the product is toxic, yet on the web site it is described as bio degradable! Can it be both? I intend to use it on block paving (and
This product is 90% biodegradable and the toxic warning sign is referring to the product being extremely dangerous to aquatic organisms. The warning sign for the skin is to make you aware of skin and eye irritation, so wear protective gloves and eye protection. The block paving seal will not be affected, however, avoid contact with plants, as this may cause damage.
Hi, is this product safe for children and animals please
Once the product has dried, it is safe for children and pets to return to the treated areas.
If this gets on artificial grass, will it harm it?
This will not harm artificial grass. 
Hi, I have just bought some spray and walk away algae and moss remover and I want to check please if it is ok to spray on Cotswold stone chippings which are quite porous. My young son does like to pick them up and play with them so I want to know if this
Yes, this product is safe to spray on Cotswold stone. It is also safe to use around children and pets but only allow them into the treated area when the product has dried. 
Hi, can this been used on tarmac please?
This can be used on tarmac.
Could you tell me whether this product is safe to use on a pontoon given the close proximity to a river and aquatic life? Thanks
We would not advise you to use in this manner. This product should not be allowed to flow directly into rivers where there is aquatic life.
Hi. Will this stuff work on grave on my drive? The once cream stones are going green. Thanks Sarah
Yes, this product will remove any moss, mould or algae on the gravel on your drive.
What time of year can this product be used
Any time of year. But avoid using in direct sunlight and when rain is eminent.
what sort of spray do I need to apply this product?
This product can be applied with a trigger spray pump or a watering can.
I have a flat roof which is felted, would this product be suitable and do the job.
Yes, this product can be used on a flat roof which is felted.
Can this be used on roof slates?
Yes, this can be used on roof slates. However, the run off must not enter waterways leading to rivers, streams etc as the product can be dangerous to aquatic life.
Can this be used on a carpet tennis court?
We would not advise you to use on a carpet tennis court.
What happens if there is run off into a lawn and borders?l
It would damage the lawn and borders, so do not use if you cannot avoid run off.
Can this be used on Rubber roof?
This product can be used on a rubber roof.
I notice this product can be used on tarmac drives, but if there is a run off onto borders will it not soak through to underground and possibly not affect any plants, although will it affect the root systems of plants. I have a path with borders either side so it is difficult to prevent some run off. Also does this product kill Lychen as well.
It can have a minor effect on grass but if used diluted with very minor run off it should be fine. The product does kill Lichen but needs to be used neat or using our Ultima XP product neat as Lichen is very tough to eradicate.
can it be used on outside sparred walls of house which are painted witout discolouring paint?
This product should not discolour paint if the dilution rate is adhered to.
Can we use it on mono blocks and bricks.
Yes, this product can be used on mono blocks and bricks.
Can it be used on brick and mortar (house wall) the answer on the website isn't clear.
Yes it can
Does simply spray and walk away get rid of lichen on patio pls.
This may struggle to remove lichen, so we would recommend the Ultima Plus XP. Thick or stubborn patches may need the product to be used neat. 
Is the product equally effective if applied during winter months? The fences to be treated are more accessible now than they will be in another few weeks.
It can be used in Winter, but avoid using when frost is imminent, as this product is mainly water based.
I have used this on my slabs and it has left a white residue will this disappear
Yes it will this is perfectly normal and temporary 
Will it remove lichen?
Used neat it will have some effect, although we would recommend the Ultima Plus XP Moss Killer as it is stronger for Lichen
I have black limestond paving.Its covered in algae from where i jetwashed the wall round the paving and has soread right across the patio.Is this product suitable to use on natural stone.I am wanting to seal the patio once the algae has been killed/removed.
Yes the product will work very well in this scenario 
Can this be used on tanalised timber decking?
This product has not been tested on tanalised timber but is suitable for most hard timbers. We would advise you to do a small inconspicuous spot first before applying liberally. 
Can this product be used on outdoor artificial cricket pitches without affecting the carpet ?
We would not advise you to use this product on a carpet cricket pitch.
I have a black limestone patio which product would you recommend, also is it best to wash the patio a couple of days after application. Many thanks.Jon.
This product is suitable for black limestone. It should not need washing off, after application, if you follow the correct dilution rate. 
can this product be used on composite decking
Yes, this product can be used on composite decking.
Can this product be used successfully on painted pebble-dash walls ?
Yes, it can be used in this manner.
Hi is this product harmful to dogs
This product is not harmful to dogs. However, we would advise you to allow the treated area to dry before allowing pets back.
Can this product be used on rough cast walls ?
Yes, this product can be used on rough cast walls.
Can I use this product on my boat canopy?
This product can be used on your boat canopy but ONLY if the boat is dry docked (on dry land). This product is harmful to aquatic life and must not be allowed to enter waterways.

Does the chemicals give off any harmful fumes
Simply Spray and Walk Away does not give off harmful fumes.
Can this be used on cabriolet car roofs?
We would not advise you to use this on cabriolet car roofs. We do have a product that is more suitable below:
Does your product stain Indian Sandstone? I have read that similar treatments do cause red-brown stains
This product should not damage the colour of the sandstone. However, we would always recommend to test a small area first.
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