Enter your pool volume and target borate level — get the borax and muriatic acid doses, split into safe alternating rounds.
Total doses
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| Muriatic acid (31.45%) alongside | — |
| Add in rounds of | — |
Alternate: one round of borax, its share of acid, one hour of circulation, retest pH, repeat. Never mix the two directly. Test borates with borate strips after 24 hours.
The borate dosing math
borax lbs = 0.74 × (gallons ÷ 10,000) × ppm increase
acid fl oz ≈ 8 × borax lbs (31.45% muriatic)
The pairing is the whole technique: borax delivers the borates but drags pH upward, and the acid cancels that rise as you go. Done in alternating rounds with circulation between, pH never leaves the safe band — done all at once, you'd spike pH past 8.5 and cloud the water.
A worked example
A 15,000-gallon pool going from 0 to 40 ppm: 0.74 × 1.5 × 40 ≈ 44 lbs of borax (eleven 4-lb boxes) with about 355 fl oz — 2.8 gallons — of muriatic acid, spread over three or four rounds across a day or two. It's the biggest single chemical project most pools ever get, which is why it's worth doing the staging properly once and then enjoying it for years.
Is it worth it?
Honest answer: it's a luxury with real benefits, best suited to salt water pools (whose cells drive constant pH rise — borates cut acid demand noticeably) and owners tired of chasing pH. If your pool already holds pH steadily, spend the ~$40 of borax money on a good test kit instead.
Frequently asked questions
What do borates do for a pool?
At 30–50 ppm they act as a second pH buffer (slowing the upward drift that salt and busy pools fight constantly), mildly suppress algae, and give water a noticeably silky feel. It's a one-time upgrade — borates only leave with splash-out and drained water.
How much borax do I add to my pool?
About 7.4 lbs of plain borax (like 20 Mule Team) raises borates 10 ppm in 10,000 gallons. A 15,000-gallon pool going from 0 to 40 ppm needs roughly 44 lbs — plus muriatic acid alongside it, because borax pushes pH up hard.
Why do I need acid with the borax?
Borax is strongly alkaline: every 12 oz needs about 6 fl oz of full-strength muriatic acid to hold pH steady. Add them in alternating small rounds — borax, acid, circulate, repeat — never the whole dose at once.
Is 50 ppm borate safe?
50 ppm is the maximum recommended level (and a legal ceiling in some jurisdictions) — target 30–50 and don't exceed it. Keep pets from drinking pool water as a habit regardless; borates make that mildly more important for dogs who treat the pool as a water bowl.