Deca, sorry for the delay - I had to go to a family reunion (in-laws ) this weekend.

As for the Muriatic, Pat has some posts here about NOT using the pH- on SWCG pools because the sulfides can damage the cells.

There is no way to lengthen the cord without voiding the warranty Depending on a few variables, especially temp, the unit can read +/- 500 ppm - I trust the default most of the time, I use the instant just to check when the main display is 'funky' You should have the pool circulate a couple hours before fully trusting either - and never trust either until 24 hours after adding salt.

What I start ~ all our SWCG pools at is 50% and adjust from there depending on CYA, sun, usage... before doing any major chemical additions, get the kit, run the tests and post the numbers here - one of us will tell you what you need to add or not add to the pool