Just started - help understanding water readings

[bwspa]

So I just filled and fired up the tub. It's up to 97° so I'll be dialing when I return from the movies.  My tub came with inline @ease.  According to instructions, I need to balance TA, then pH, then CH before adding the shock pack a and two cartridges.

My readings on all three were at Max values of the strip.  I'm confused on how to bring down TA.  The chemical starter pack came with a bottle of both pH up and down.  Would I use pH down to decrease TA? instructions say not to focus on pH until TA is right, so if I use pH down, won't I be bringing both down together (which I do need).

Second question is how to bring down the high CH? I have a bottle of calcium up but nothing to reduce.  I'm on city water.

[bradleyabell]

To reduce the TA you would use PH down as that will reduce both the ph and TA.

I’m not sure if there’s a way to reduce calcium hardness. You may need to refill the tub with an insert on the hose that will stop the calcium. But wait to hear from other people who are much more knowledgeable on this.

[bwspa]

My spa is 450gal.  I initially added 2 tblsp of pH down, waited and no change, 2 tblsp more.  No change, added 4tblsp before bed (all within a few hours).  Since we used the tub for a good hour or so in the evening, I went ahead and put the shock pack in. Checked it 7 hours later, the TA is down to 180 and CH is about 450 (was 240 / 800).  PH is still closer to the 8.4 color than 7.8, so I tossed in 6 more tblsp.  Hope I'm heading in the right direction.

[The Wizard of Spas]

As bradleyabell noted, use a pre-filter that will attach to your hose when filling.  Be sure the pre-filter reduces calcium, as not all pre-filters are the same.  TA and pH are best reduced when the water is calm.  Its just something I have found over the years:  Add X amount (be sure to keep track of how much pH lower you need to use this time to get your TA down so that next time you can just add it to the footwell when you refill your tub) to the tub and don't turn the jets on.  To be clear:  You'll be fine if you do.  But I've noticed you get much more out of leaving the jets off and keeping the water calm when you are trying to reduce pH/TA. 

I'd also go to your local dealer and get your water test.  Strips are fine.  But I'd take your tap water to your dealer and get a better read on what it is.  Do this once and save your read-out so that you always know what your baseline will be when you re-fill your tub. 

And as always, @ease is ALL ABOUT pH!  Keep that in-line, always and without fail.  Note that you're chlorine is BY DESIGN supposed to be at 0.5 to 1.0, with TOTAL CHLORINE at 10-15ppm.  Good luck moving forward.