It's a commercial job I can't tell them that the lichen will wash away after a couple rains. Is that how you clean your roofs without rinsing. Or will your mix work without anything happening. I'm still confused about dwell time if your not rinsing. Sorry to be a pain in the ass.
We would all like to simply dip our meat in Terayki Sauce, but for maximum flavor, we soak our meat (marinate) it overnight.
Same with algae and
especially Lichens. Do NOT rinse the roof, allow the algae and Lichens to "marinate" in the Love!
Just like you might take Antibiotics for a few weeks to fully Kill an Infection, you need to allow the Sauce to dwell on the roof as long as possible. Bleach does not always kill completely on contact, so simply leave it on the roof, and let God rinse it.
If you are hardheaded, and will not listen to us, and feel you must rinse, here is what to do.
Clean the roof, then go eat lunch, play pool, whatever, and come back an hour later. Then rinse, after an hours dwell time.
But, whatever you do, do not ever rinse a roof w/o allowing at least an hours dwell time.