Pool-chemical safety: Follow the sanitizer label and the feeder’s shutdown, pressure-relief, refill, and service instructions. Keep products in their original containers and never mix chlorine chemistries. See the CDC pool-chemical safety guidance .

A tablet can last a few days in one approved setup and materially longer in another. That difference is not a quality score. The useful question is whether the feeder maintains the required water result without running empty between checks.

Turn refill history into a conservative inspection plan

Record the start and end of each actual operating period, not just the number of tablets purchased. Suppose two otherwise comparable periods lasted six and four days before the next permitted refill inspection. An average of five days hides the shorter result. Plan the next inspection before the earliest depletion you have observed, following the manual, and continue normal water testing throughout.

Keep unlike periods separate. A week with a changed pump schedule, a new tablet product, a cover change or heavy swimming does not validate the old interval. Note that change beside the dates rather than combining it into an average. Never deliberately run the feeder empty to measure its capacity.

The observation has two limits: it describes past tablet consumption, and it applies only to the recorded conditions. It does not certify future chlorine levels or establish how long the pool can be left unattended. Arrange a competent carer for an absence even if the chamber appears to hold enough tablets.

Why a fixed day range is misleading

Tablet erosion changes with:

  • the feeder model and internal water path;
  • the tablet chemistry, size, shape, and formulation;
  • feeder setting and chamber load;
  • pump speed and run time;
  • water temperature;
  • scale, debris, or a restriction in the feed path;
  • whether tablets bridge, fuse, or remain evenly exposed to water.

Pool chlorine demand also changes with sunlight, swimmers, debris, and contamination. Demand affects the measured free-chlorine result. It should not be confused with tablet erosion: a pool can consume chlorine quickly even when the tablets appear to dissolve normally.

Use three records together

Record What it tells you What it cannot prove
Free-chlorine and pH tests Whether the water remains within the applicable target Which single variable caused a change
Feeder setting and pump schedule The operating conditions for that test A guaranteed dose from the dial number
Refill date and remaining tablets When to inspect and plan the next refill That the water is safe or balanced

Keep the records at comparable times. The feeder dosing-rate guide explains how to adjust one allowed input at a time without inventing a universal calibration formula.

Establish the first refill check

  1. Confirm the exact feeder model and sanitizer label.
  2. Verify the permitted tablet chemistry and size.
  3. Start with the loading amount and setting given by those instructions.
  4. Keep the normal pump schedule documented.
  5. Test at the interval required by the label, manual, and test-kit directions.
  6. Inspect the feeder before it is likely to run empty.
  7. Record the remaining material and water result.

Use that first cycle to schedule the next inspection. Do not wait for free chlorine to fall or for the chamber to become completely empty.

Read fast or slow disappearance carefully

If tablets disappear sooner than expected, check whether the feeder setting, pump schedule, water temperature, or tablet product changed. Inspect for damage or an unintended high-flow condition using the manual.

If tablets remain much longer than expected, check for low or blocked flow, scale, fused tablets, a changed pump schedule, or a feeder setting that is not operating as assumed.

In either case, test the water before changing output. Visible tablet life does not tell you whether the pool is underchlorinated or overchlorinated.

Tablet diameter is model-specific

Several 1-inch tablets can expose more total surface to water than one 3-inch tablet, but that observation is not permission to substitute sizes. Some feeders allow more than one diameter and describe how each behaves. Others approve only one size. The 1-inch versus 3-inch comparison covers the manufacturer examples.

Use the exact manual. Never cut or crush a tablet, never add granules, and never combine products from different containers to fill the chamber.

Refill without creating a mixing hazard

Before opening a plumbed feeder, follow its shutdown and pressure-relief sequence exactly. Some models require a timed sequence of valve and pump steps. Do not generalize one feeder’s procedure to another.

During service:

  • use the protective equipment named by the label;
  • keep your face away from the opening;
  • add only clean, approved tablets;
  • inspect the cap, seal, tubing, fittings, and flow control as the manual directs;
  • use only the lubricant specified by the manufacturer;
  • close and restart the system in the stated sequence;
  • check for leaks.

Do not rinse residue to soil, a drain, or a paved surface. Do not store the tablet container at the equipment pad unless that location satisfies the product-label storage requirements.

Track the chemistry added by the tablets

Many slow-dissolving tablets are trichlor. Trichlor adds cyanuric acid and tends to lower pH. A refill log can therefore look predictable while the broader water balance moves away from the intended range.

Use the water tests required by the sanitizer label and pool instructions. If continued tablet use no longer fits the water balance, changing the refill interval is not the solution.

The right answer is a check date

Do not ask a generic chart to predict how many days a tablet will last. Use the manual and label to start, then use repeated tests and observed refill history to set the next inspection before the feeder can run empty.

The aim is a verified water result, not the longest tablet life.

Sources

Before buying a larger chamber, compare documented feeder capacities and plumbing requirements .