Non-bio is best for general laundry and items that need to be washed at a higher temperature such as sheets and towels.
Bio contains enzymes that digest food and fat stains, and works best at 40C (anything higher kills the enzyme). Great for kids’ clothes. Don’t use on silk or wool as it can weaken the fibres.
Some people reckon that bio detergents can irritate skin, but there is no hard evidence to suggest this is true – it’s thought that it’s more likely to be the perfume in the detergent. If someone in your household has eczema, try adding an extra rinse or two to the cycle.
Laundry balls In my experience, if your items are stained, the balls are pretty useless at removing them.