JC, it seems the in-laws found a new machine to rinse their suits.
To all others, do not allow Tee shirts, cut-offs or other clothing articles that continue to hold phosphates in the fabric. Solve the problem, not the symptom. Prevent the introduction of residual soap into the tub and minimize ANY anti foam you may use, it will cause another set of problems.
Mix or dilute anti-foam in a spray bottle 50-50 with water and SPRay it on the foam = same effect, less chemicals, less cost, less residual aftermath. Best recommendation is the first recommendation.