coigula - Vinegar is fine. The HCL works quickly, and thus I can get the task done instead of having to wait a long time. In all the years of using acid to clean equipment, I've never had anything damaged or fail after the fact. Matter of fact, I usually end up tossing out equipment that is simply too old to be reliable, not because it has failed. Decluttering, so to speak. If you are staying on top of the cleaning, there is no need for stronger methods obviously. And the key is that I don't leave it in solution for longer periods of time. What's the reason for the bigger sump pump versus a larger skimmer?

TomNeely - You're welcome.