[justin cooper]

I had a big sandstone patio clean today it was divided it to two parts. I started the smallest half, cleaned with fsc it took off 90% of the marks/dirt stuck hypo down and it looked great job done. Thought this would be an easy job


Started on the bigger half which  was full of weeds and pointing was wrecked, went over with fsc and it hardly touched it put hypo down and repeated and repeated  finally used neat hypo but the lichen just wouldn't budge ? Removed most  but there was a few bad slabs all in the same area that I couldn't get right.

It's the first time I've not been able to completely remove the lichen. I made sure hypo didn't dry out not sure what went wrong any one else every had one that they couldn't completely  remove?

[wpclean]

Did you try a turbo nozzle on it, usually does the trick ?

[justin cooper]

Did you try a turbo nozzle on it, usually does the trick ?

Yes it removed a bit but there was still a few slabs that looked crap.

[wpclean]

What machine are you using ?

[justin cooper]

Gx390 21l , machine was running fine couldnt get the turbo any closer without tearing the stone apart, and Im pretty  sure hypo was good so not sure why I could shift it.

[Tadgh O Shea]

Scrub the lichen with a stainless steel scouring pad as they are more effective than using a turbo nozzle, if your custy has left their patio slabs go that far you can justify the extra pricing for all the extra work required to remove the tough lichen, if they are not prepared to pay the extra just tell them  you will have to leave the very old lichen, as i have shared before stainless steel scouring pads will eat through the toughest of lichen without damaging the surface of the slabs.

[wpclean]

How old is the Hypo, it can go off pretty quickly if it is left in direct sunlight ?

[Smudger]

IMO (for its worth)  using the FSC first seems to make the stains and lichen more stubborn - anything bad we away so turbo ( now only use FSC. For non weed/light cleaning areas )

Below is the worst lichen I have had, removed approx 99% of it, add detergent to your hypo to help it stick ( less run off ) below needed 100% strength application (spot treatments) to the most stubborn bits

[justin cooper]

I've never added detergent too the hypo ill give that ago see if it makes a difference. Think I'm going to try a new supplier  as well I've always bought it from the same place so I can't compare  it to any thing.