(1) In experiment in a midpoint (with fixed 50% vol. water / acetonitrile ratio and 0.5 to 8 eq. BODIPY-C18 concentrations) global fit for 5 concentrations yields similar lifetime values of 5.3 and 7.4 ns (Figure ). We still observe separation onto two ensembles, but dye concentration change does not affect their ratio to a significant extent. This indicates that second long component is solely responsible to water content. This also points that aggregate size is concentration-independent since dye within aggregates in a broad concentration range is available to water to the same extent.