I recently bought a hot springs spa from a friend and it sat in his yard for a while. He tells me he did not have this problem when he used it. A white-yellow sticky scum keeps appearing on my water line followed by a rash and i can't get rid of it. I've tried bleach, cascade, system flush and some other flusher, plus replaced all the hosing attached to all the pumps. The place i find most of the build up is in the heating element, looks like cocoons in there after only a couple days. All my chemical readings are right on. Can anyone help or is this tub a lost cause?????

It sounds like some kind of water mold. I'd try an extended cold soak with high chlorine solution.

Drain and fill it and keep the heat as low as possible. Add 2 or 3 times the normal amount of chlorine (I'd use di-chlor) and let it soak for a couple of days. Run the jets a few times a day to get the water circulating. Then drain and fill and go back to your regular chemicals. Good Luck!