Here is something to consider...
Distilled White Vinegar is a mixture of water with 5% acetic acid, nothing else.
Any lemon juice products may include things like chemical preservatives and even sweeteners. i dont think you want that run thru your machine.
you should run the Distilled White Vinegar mixture thru the entire system, because scale builds up everywhere the water goes. in fact the Scale will impact your system more in the fluid lines and small openings.
here is what my dad uses in his shop...
Dilution 1:1 - one part water mixed with one part Distilled White Vinegar
run the solution thru a hot machine ONCE and discard.
Rinse machine immediately twice with Fresh clean water. after that there should be Zero odor and a clean machine. this should be done at least once every two months, or once a month if you have very hard water.
acetic acid is the main ingredient in most espresso machine cleaners, some add a detergent. Check the price difference. it is also easier to mix than the dry packaged cleaners. Win-Win, cheaper and easier!