Chasing LSI on the spa side, pool stays clear but jets keep scaling

Started by Karen Delgado · · 1 reply
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#1
Fill water here is over 400 ppm calcium so I know the drill, run pH low, keep an eye on the Blue Stuff dose. Pool tile line stays clean doing that. Spa is a different animal, same water, same chemistry, but the jets and the spillway lip are crusting up every few weeks while the pool side barely needs a wipe down.

Only difference I can think of is spa runs hotter and the jets add a ton of turbulence, so CO2 outgassing and pH rise happening faster there than in the pool. Anyone actually calculated LSI separately for spa temp versus pool temp, or is everybody just eyeballing it and running acid a little heavier before spa days. Not looking for a miracle product, just want to know if I'm missing a step or if hot turbulent water is just going to scale no matter what I do.

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#2
Yeah the temp delta on LSI is real, that's not you overthinking it, higher temp pushes the number up even with identical pH/alk/CH. Before I'd chase acid dosing harder though, what's your alkalinity sitting at on the spa when this happens, same as pool or have you let it drift up. Because with 400ppm fill water if alk is also high the spa heat is just going to tip it into scaling territory way faster and pH will keep climbing on you no matter how much acid you dump in right before a spa day.