I get foamy water every spring, lasts 2-3 weeks, then stops. This is the Only time of year I change any water. I add nothing to the pond to get rid of it. My theory is the once the submerged plants get growing well, the foam stops. Anacharis, Valisineria, millfoil, stuff like that. marginals, floaters, and water lilies have no effect on foamy water.
7 years with this pond, mind you all, only do wc in the early spring. keep LOTS of submerged oxygenators. when they get too big, remove large pieces of them. This takes the place of water changes,
IMO. I remove large quantities of plant material (pure organics, understand?).
A pond is NOT an entirely closed system. It rains, pond overflows, ergo nature's water changes.
BCman, my bet is this, you change 15% (or whatever), foam will cut back for 2-3 days, then come back same as it is.
Put in some submerged oxegenators, do nothing else, foam gone in 2-3 weeks, depending on how much veg. you put in.
