Black spots on back garden slabs - Help/advice needed

[Breadfish]

Like everyone else during this lockdown attention and focus has been put on household chores you always mean to get too, but always find an excuse not to do.

Anyway, after jetwashkng the backyard a number of times have come across these black dots which are on the tiles that are impossible to remove.

I have bought several products, left them to soak in and scrubbed till my hands are red raw, yet these black dots are still present. I'm led to believe its something called lichen or something like that.

Please for the love of god can someone give me some tips on what j can use to not only get rid of the stuff, but prevent it from appearing again.

I've looked online and there seems to be a few 'miracle' cleaners but I am sceptical.

The best thing I have used this far actually is proper bleach, however it was so time consuming to do a small spot, and even then it only faded them, did not remove a full black dot.

Many thanks

[RAPressureWashing]

If you go to the main site, and find the stain removals page, there is a thread/post on there, it is the Berries stain removal from memory, have a read of that, it is a mixture that we use daily, you do the whole paving not the individual spots.
Instructions are easy enough to follow.

[Tony McC]

This is the link you mean, Roger... https://www.pavingexpert.com/stains#berries-and-fruit

The black spots are lichens and this is the latest outpouring I posted.... https://www.pavingexpert.com/maintain_04

..and then it's always worth reading...... https://www.pavingexpert.com/maintain_03



Edited By Tony McC on 1590151153

[RAPressureWashing]

This is the link you mean, Roger... https://www.pavingexpert.com/stains#berries-and-fruit

The black spots are lichens and this is the latest outpouring I posted.... https://www.pavingexpert.com/maintain_04

..and then it's always worth reading...... https://www.pavingexpert.com/maintain_03

Biocides are fine, except what I do everyone wants "Now" or immediate results, and offering that service it has to be achieved on the day or days etc.

Lots of people are going the biocide route, there are some good ones out there, but a few things have to be considered and labels read etc and some don't I'm afraid and accidents are waiting to happen.

The hypo solution (the berries one) I use, is tried and tested, and as long as people take care etc, it is fine to use, bit of common sense is all that is needed.

[Tony McC]

I wouldn't want to take any work away from you, Roger, and I do repeatedly make the point about the better-quality biocides not providing immediate or even 'pretty quick' results, but they are a growing phenomenon (a bit like the lichens!) and will help ameliorate the worst effect of "blackspot" for many users....but there will probably always be a need for professional cleaning. After all, biocides can't treat all stains......

[RAPressureWashing]

The best biocide in a professional in my view is Algoclear, tried and tested ticks all the boxes, but a new kid has come on to the block, GK Pro, and hearing good results from it.

Biocides are getting more and more popular that is true, nothing wrong with them, it just depends on the client, some want it clean now, some will wait?

For me, deep clean year one, and then you can follow up with biocide, and they do take time but work, or deep clean year one and go onto a maintenance clean yearly, most of my clients go for the latter, it's their choice at the end of the day.