Well your questions do not reflect what the manual is saying to do. Like this…
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It seems that you are looking for ways to deviate from recommended and accepted practices. Even the so called pros mess it up when they begin freelancing.
Example…
Manufacturers recommend to loop the spa. Are you asking if some folks don’t follow what is in the manual? Why?
Also manuals often gloss over key steps that they assume a professional plumber always knows.
Your postings reference your gut instead of the manuals you are looking to follow.