Use the same solvent composition as the foam. Add the metal ions at their maximum solubility concentration in a volume that will give you the final 1% needed. You may need to make it alkaline for solubility increase (depending on your salts you are using).
Thank you so much . But what kind of solvent do I use ? Once I used ethylene glycol as solvent and FeSO4 , MnSO4 and Br , but it caused the foam todry out early. what is solvent of the foam in spray?