[trevor perry]

a bit of disinfectant in waste tank stops it foaming

[calmore]

Yes Mark I remember why I used it many years ago, but moved away from products likely to leave a residue about 10 years ago eliminating the need for defoamer.

rob

I find that a lot of customers have tried various products that cause havoc with foam.

I always put a scoop in the tank "just in case"!

[richardc1983]

salt or fabric conditioner also acts as a defoamer.

U can use just the cheap supermarket no frills brand!