Leather,

You got it, when the engine stops running or has a noticible power loss. That's when I replace mine. Its such a simple roadside fix, its no problem to me.

I think I have an algae problem in the one SD. It plugs it's filters much more often than the other SD. I tried to get some algaeside locally but haven't found any, maybe its not a popular product in the north.

Going to AZ and NV soon, maybe I can find some there or on the way.

P E H