Cleaning brick work with 30 seconds

Hi guys- I've got some brick work which has moss and mould on it- pretty slimy. I have scrubbed and washed it with sugar soap and that's taken away some of the black stuff. Just used 30 seconds and left it on for 15 minutes and hosed it down. Can you leave that 30 seconds stuff on the brickwork and not rise it off- just wait for it to kill the mould like wet and forget? Anyone done it?

why don't you phone the 30seconds people & ask? (or email them)

I suppose the brick work is paving or perhaps a garden wall. Moss will form on brickwork when it is continually wet. It should not form on a wall veneer.
Sugar soap is not the best treatment Washing powder gives an immediate improvement but is expensive and not completely satisfactory
Wet and forget (benzyl konium ? chloride is a good initial treatment but I would leave it on for a few months. There are cheaper sources of this called one step ? from mitre10 Check the label for benzyl? . It will kill some of the moss or lichen but will still leave a bit of black discolouration.
The best thing to do is to use benzyl? followed by sodium hydroxide diluted 1:5 and apply it with a soft broom. Be careful this is very corrosive to the skin. It lifts the colour of the bricks. Now is a good time to put it on but it will show no result until there has been some heavy rain. It can also be put on wet bricks but there needs to be a dry period so it is not washed off . The effect of this is long lasting

Many cleaning chemicals are rinsed off before they have worked their majic, you will find that the cleaning results are much better if chemical is left on for 12 or more hours. Brick is fired clay and is not affected by the cleaners commonly available.

I have some high strength benzylkonium chloride < 50% strength sold as a pool algaecide. I believe if I use a 2% strength, so about 1: 25 ratio it will be effective. Is this ok for use on pine decking do you think? Sounds like I need to leave it on for a day then?

Wendalls
The benzylkonium chloride I have is 99 g/l and it is diluted for use 1:4 so your calculation sounds OK to me. I would just put it on with the garden spray and leave it. I think the idea is that you put it on and it kills the algea? and then the rain washes the dead stuff away.
I use this on quilla decking and when it is dry apply decking oil After you have put the benzylkonium chloride on and there is a lot of moss you would need to scrub it off to remove the dead stuff. I would scrub off after a day or two and then wait a few more days for the deck to dry before oiling

If it is a bleach based product like 30 seconds, then it will bleach in a short time period just like your dish cloth/sponge, so there is no advantage in leaving it on. The other Moss n Mould kills work differently activating each time it rains, and will be effective for up to a year.

That was helpful Not when this is a place to ask about "gardening and diy"

depends which 30 seconds you used. The one in the blue/white container you need to hose off, the one in the green/white you can leave on. It is dearer than the other one but works much better in my experience.