Foam, entrained and dissolved air that are present in coolants and processing liquids, may cause various kinds of problems, including:
* Reduction of pump efficiency (cavitation)
* Reduced capacity of pumps and storage tanks
* Bacterial growth
* Dirt flotation / deposit formation
* Reduced effectiveness of the fluid solution(s)
* Eventual downtime to clean tanks
* Drainage problems in sieves and filters
* Formation problems (i.e. in a paper mill it may cause the fibers to form an inhomogeneous sheet)
* Cost of replenishing the liquid
* Cost of entire material rejection due to imperfections