PoolDose
Summer
Every dose scales straight off pool volume. These are the per‑10,000‑gallon rates the app uses, so you can check any number by hand.
| Liquid chlorine 12.5% | 10.2 fl oz = 1 ppm FC |
| Liquid chlorine 10% | 12.8 fl oz = 1 ppm FC |
| Cal hypo 73% | 1.8 oz = 1 ppm FC (+0.7 ppm CH) |
| Cal hypo 65% | 2.1 oz = 1 ppm FC |
| Trichlor 3" tab (8 oz, 90%) | 5.4 ppm FC + 3.3 ppm CYA |
| Baking soda (pH + TA) | 1.5 lb = +10 TA, pH follows |
| Soda ash (pH only) | 3 oz = +0.1 pH (+0.6 TA) |
| Muriatic acid 31.45% | 26 fl oz = −0.4 pH (−10 TA) |
| Dry acid | 10 oz = −0.4 pH (−7.5 TA) |
Which one: bicarbonate is the default for every low‑pH call. It is what is on the truck and it cannot overshoot pH. Soda ash only earns its place when pH is under 6.9 and alkalinity is already adequate — then bicarbonate would just push TA over 100 and pH would barely move. Most trucks do not carry soda ash; if pH is low and TA is already at 100, aerate instead (jets up, water features) and pH comes up for free.
| Calcium carbonate | 1 lb = +12 CH |
| Cyanuric acid, granular | 1 lb = +12 CYA |
| Salt | 1 lb = +12 ppm · 40 lb bag = 480 |
Salt is measured in ppm, so a good reading is 3,200 ppm — which is the same thing as "3.2 thousand", or 3.2 ppt. Testers print ppm, so type the number you see. The band is 3,000–4,000 ppm with 2,800 as the floor; cells shut down somewhere above 4,500, so a pool sitting at 4,200 is not a problem, it just gets no salt this visit. Salt only leaves the pool by splash-out, backwash and draining, so a pool that needs salt every visit is losing water, not salt.
Every pool is dosed to 5 ppm free chlorine on the weekly visit, all year round. Five is high enough that a week of burn-off still leaves chlorine working in the water, and it doubles as the weekly shock. The burn-off is the knob you actually tune: cold water burns about 0.5 ppm a day, a Texas July pool with bathers 2–3. A pool that reads 0 next week is telling you the burn-off number was too low and the dose needs to be bigger.
Combined chlorine over 0.5 means SLAM. Shock to 40% of CYA and maintain it — retest and dose back to that level twice a day, brush walls and floor, run the filter 24 hours, clean it when pressure climbs 25% above clean. Finished when CC is 0.5 or less, the water is clear, and it holds overnight (1 ppm or less lost between dusk and dawn). No tabs during a SLAM — trichlor cannot hold a shock level and it spends CYA you cannot get back.
CYA never evaporates and is not touched by shock — only fresh water lowers it. A tab pool tops out at 90 ppm, a salt pool at 120. From 80 on, every tab spends headroom you cannot get back; under 40 the sun eats your chlorine and the answer is more tabs or granular stabilizer. Each 3" tab adds about 3.3 ppm per 10,000 gal. High CYA in late summer and fall is normal on a tab route — do not sell a drain: pull the tabs, carry the pool on cal hypo (liquid while calcium is over 400) and let backwash, splash-out and winter rain take it down.
That is why the FC target here follows CYA: 7.5% of CYA is the minimum before algae can take hold, 12.5% is the working target. CYA 40 → min 3, target 5. CYA 80 → min 6, target 10. Chlorine at 5 ppm in a CYA 80 pool is under‑chlorinated.
Everything granular is quoted in orange scoops — the big orange DE scoop from SCP (CMP/Super-Pro 25600-006-000), because that is the one on the truck. A full one is 48 fl oz of volume: it holds a pound of DE but 3½ lb of bicarbonate and 4 lb of cal hypo, because the products pack differently. That is why a "1 lb scoop" of cal hypo weighs 4 lb.
The blue scoop is the small one in a cal hypo bucket — about a third of the orange (2¾ blue = 1 orange). Cal hypo doses also show the blue count in case that is what is in your hand.
Check it once: a heaped orange scoop of bicarbonate should weigh about 3½ lb. If yours weighs closer to 2 lb, set the orange scoop to 27 fl oz below and every dose recalculates.
Plaster/gunite surface, 200–400 CH. For vinyl or fiberglass, ignore the calcium card unless CH is very high. Calcium carbonate is 1 lb per 12 ppm per 10,000 gal by weight — it dissolves slowly, so it reads low for a day.
Cold water (under 60°F) drops chlorine demand a lot, so winter FC targets are lower and cal hypo does the heavy lifting.