Hello my friends of solar cleaning! A little about us: we are a small solar cleaning company in Baden-Württemberg, Germany, near Freiburg im Breisgau. We clean with the Solar Cleano F1 and M1. Everything is done with a reverse osmosis system. Unfortunately, we still have problems with lichen. We've tried countless cleaning products, including Chemitekk. Do you have any tips regarding Chemitekk dosage/application? Do you have any other experiences? I'd be happy to discuss this with you. Sincerely, Severin Solar Cleaning