I can add or limit the number of bromine tablet to main the TBr. However, how do I adjust the FCl (free chlorine ppm), Alk (alkalinity ppm), pH, and Hard (total hardness ppm)?

I'm looking for install tips for putting a spa pack in a basement and don't see much information available for DIY. Can anyone point out a place where such info might be found? A few particular concerns: - Loss of head. Pipe run will be about 18 feet and I can get the pump about 1-2 feet lower than it would be for ground level install. Is this enough of a difference that we'll notice the pressure difference? I can run the outdoor run about 8 feet through 2" rigid instead of 1.5" flex pipe if that would help. I might prefer to do that anyhow as an easier way to enclose and insulate that 10' pipe run. - Water in the basement. Are spa packs prone to flooding events? What are the odds that I'll someday find 600 gallons of water in the basement, and how can I reduce the odds of that happening? I can't even find good advice for simple things like filter changes online! Just cleaned up a minor flood on a whole-house sediment filter that might have been caused by the sub-zero weather changing the seal on the threads enough that it leaked, maybe 20 gallons before I caught that one. - Separate cutoff from spa panel. I don't see any advice on how to wire these! Tempted to just run a switch and trigger the GFCI with 8 milli-amps of current @ 110 vac across about 10K ohms, though that certainly won't get approval from our electrical inspector. Any advice on what particular relay to use? I see some DP contactors that look like they can switch the 40 amp 220vac service. It looks like there are a number of spa panels with GFCI and two spare spaces . Seems I really want 3 spare spaces so I can also run 110VAC GFCI outdoors.. Any suggestions on the whole electric setup? Thanks for any advice! Charlie