iron sulfate is used in ocher paint for wood (or flour paint) as a fungicide and as a mordant. It helps to dilate the pores of the wood to make the oil penetrate and also allows to create a slight saponification of the oil so that it can be diluted with water. ocher or flour paint then becomes an oil paint which is diluted with water.
also iron sulfate improves the performance of septic tanks. Very useful and very effective in diluting, deodorizing and eliminating bad odors while cleaning the pipes and the septic tank itself. Use: Pour the iron sulfate into the septic tank directly or by incorporating it through the toilet bowl. The use of iron sulphate in the septic tank must be done once a year or even twice a maximum. Dosage: The recommended dose is 4kg per 100L.