Lichen, what lichen!! - Sandstone Patio cleaning

[Bob_A]

My l.ocal swimming shop sells it for £10.99 for 5L which seems dear but not suprising for a shop down sarf that caters for rich people.
I'm currently experimenting with 'Thin Bleach' which is 29p for 2litres from the supermarket.
It's concentration is only a third of the stuff you get in the pool shop but at 14.5p a litre it's a fraction of the price and much easier to source. Because it's weaker I've been using it neat and not diluting it.
It seems to work ok but as I haven't used the other stuff I can't make a direct comparison.

[lutonlagerlout]

rogers jollop works much better bob
i have tried thin bleach and it was a waste of time IME
LLL

[RAPressureWashing]

My l.ocal swimming shop sells it for £10.99 for 5L which seems dear but not suprising for a shop down sarf that caters for rich people.
I'm currently experimenting with 'Thin Bleach' which is 29p for 2litres from the supermarket.
It's concentration is only a third of the stuff you get in the pool shop but at 14.5p a litre it's a fraction of the price and much easier to source. Because it's weaker I've been using it neat and not diluting it.
It seems to work ok but as I haven't used the other stuff I can't make a direct comparison.

That is a bit expensive Bob, you should be looking at around £10-£15.00 for 10lts 14/15% strength this is as strong as you can buy. Thin bleach will sort of work, but you'll have to use so much of it and 6% is as strong as it will ever be unless you boost it.

[Bob_A]

The supermarket stuff says it less than 5% which is approx a third of the proper stuff and is why I'm using it neat.
The proper stuff can be used 1 part to 2 parts water so wouldn't it end up being roughly the same concentration?

Roger have you ever needed to go stronger than 2:1 ?

[lutonlagerlout]

i tried the supermarket stuff Bob it dont work
LLL

[RAPressureWashing]

The supermarket stuff says it less than 5% which is approx a third of the proper stuff and is why I'm using it neat.
The proper stuff can be used 1 part to 2 parts water so wouldn't it end up being roughly the same concentration?

Roger have you ever needed to go stronger than 2:1 ?

Bob,
No the maths looks like it should work that way, 3:1 is the same as your 6%, but it doesn't, work like that as these thin bleaches have additives etc so changes the the ratio, where as my mix Hypo and H20 will give you what you need to clean most surfaces plus is it more fluid then thick, if you see what I mean.

Have we ever needed to stronger then 2:1 yes, but you would then need to do the whole surface at the same strength to balance the surface out.

[lutonlagerlout]

think of beer as an analogy
beer gets you drunk but you need 10 pints
wine gets you drunk but you need 2 bottles
whisky drives you mad after half a bottle

its the same drug alcohol but different concentrations do different things

same with coca tea and crack and codeine and heroin
all about dosage and strength
LLL

[Bob_A]

Thanks chaps.
I shall look into getting some Sodium Hypochlorite but will try to avoid that posh swimming pool shop.

Apart from possible discolouring can this stuff actually damage Indian Sandstone?
My guess is that as it's only an alkali it won't.

[RAPressureWashing]

Thanks chaps.
I shall look into getting some Sodium Hypochlorite but will try to avoid that posh swimming pool shop.

Apart from possible discolouring can this stuff actually damage Indian Sandstone?
My guess is that as it's only an alkali it won't.

Shouldn't even dis-colour Bob with a 3:1 mix.
Yes it is alkaline.

[foiled]

Can I spay 15% of sodium hypochlorite undiluted onto Indian sandstone?
Thanks

[RAPressureWashing]

Can I spay 15% of sodium hypochlorite undiluted onto Indian sandstone?
Thanks

What are you trying remove? as I very very rarely need to use hypo neat. a 3:1 mix should get rid of most dirt & algae, if it is Lichen then step it up to 2:1, be careful with going in neat as you will have to do the whole area to balance it up.

[rimexboy]

nice work roger ... picture 2 does not work for me ...

[dpatel]

Hi - just want to check something here...when you state 2:1 I assume this means 2 parts water to 1 part Sodium Hypo (as opposed to 2 parts sodium to 1 part water)?

Also, can this be used on reconstituted slabs?

Finally, I read earlier about dwell time of 30mins. So, I only have to leave the stuff on for 30mins and then I can jet wash it off?!

[RAPressureWashing]

Hi - just want to check something here...when you state 2:1 I assume this means 2 parts water to 1 part Sodium Hypo (as opposed to 2 parts sodium to 1 part water)?

Also, can this be used on reconstituted slabs?

Finally, I read earlier about dwell time of 30mins. So, I only have to leave the stuff on for 30mins and then I can jet wash it off?!

Yes 2 parts water to 1 part Hypo, remember water first then the Hypo. Yes it can be used on reconstituted slabs.

Dwell times can vary depending on the staining or soiling. If it is algae, moss etc, then 10-15 mins should be enough, if you have Lichen, then you are going to need a longer dwell time, 20-30 mins again depends how bad it is. Yes you do jet wash off, but watch your run-off area, as Hypo will damage/kill grass and tender plants, don't use near fish ponds etc.

[Paul Faulkner]

Roger,tried a 2-1 mix on my sandstone which has bad black lichen,especially close to the edges of the slabs,but it just laughed at it! I followed your method and even tested a small patch witha neat solution for 30mins but to no effect.Have you any suggestions,I would be most grateful.