Thinking about a sequestrant before my next fill, opinions

Started by Karen Delgado · · 3 replies
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#1
Getting ready to drain a chunk of the spa water and refill, and wondering if it's worth dosing a sequestrant before the fresh water even hits calcium territory instead of waiting for scale to start. My fill water is 400 plus straight out of the tap so it's a losing fight either way. Jack's Blue Stuff is the only scale product that's actually done anything for me on the pool side, mine's been fine for four seasons, but never tried dosing preventively right at fill up versus after I already see haze on the tile. Anyone done it that way. Trying to figure out if it actually buys real time or if I'm just delaying the same drain by a month and wasting product money in the process.

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#2
With calcium at 400 ppm plus straight from the tap, dosing preventively at fill up does buy you real time because sequestrants work by tying up the calcium ions before they can pair off and crystallize on a surface, it's a lot easier to keep dissolved than to redissolve once scale's already formed. My own fill water only runs around 250 ppm calcium so I've never had to chase this on the spa side, but the chemistry holds either way, the trick is you'll need to redose on a schedule since the stuff breaks down with heat and chlorine exposure, so budget for that or you're back to the same haze in a few weeks.
#3
Never had to deal with 400 out of the tap, my fill water's soft here so calcium scale just ain't a fight I've had to fight in 30 years.

But dosing before you even see haze sounds like the right move to me, easier to keep it dissolved like Alan said than scrub it off tile later. If your Blue Stuff already works on the pool side I'd think preventive on the spa is worth the few extra bucks, spas heat up more anyway so scale's gonna want to form faster.
#4
no hot tub here so grain of salt, but the "budget for redosing on a schedule" part from alan seems like the actual answer to karen's question, not a side note. if the sequestrant breaks down with heat and chlorine and a spa's running hotter than a pool plus getting dosed more often, feels like preventive dosing isn't buying you a month, its just turning into a permanent line item every time you top off. my blue stuff on the pool side i only touch when i actually see the tile hazing up, which is maybe twice a season, so the cost stays low. if i had 400 out of the tap and a spa i think id rather just test calcium hardness with something decent, my k-2006 handles that fine, and dose reactively once its climbing instead of guessing at a preventive schedule and burning through product for a problem that mightve been weeks out anyway.