I trust no pond company. One shop here that installs ponds had a pond parade. My wife and I went on half of it. There was one pond, a big nice pond, that they did the maintenance on. When there was a problem, like green water, it was either this chemical or that. They installed Aquascape ponds with no bottom drain and gravel in the bottom. Needless to say, I don't go there for supplies.
Happy ponding,
Scott