Dosificación y control

Dosing and control for swimming pools and spas

Automatic dosing keeps water chemistry inside a narrow band without anyone standing at the poolside with a test kit. A controller reads the water continuously through a probe, compares the reading with a setpoint and switches a dosing pump or valve until the value returns. Here you will find the measurement and control side of that loop: pH and ORP controllers, continuous chlorine analysers, the electrodes and flow cells they mount in, and the reagents, tubing and small mechanical parts that are consumed in normal use.

The range is built around the Hanna Instruments Pool Line and PCA series, so most pages belong to one of two families: compact wall or panel controllers for pH and ORP, and the larger PCA analysers that measure free chlorine photometrically alongside pH.

Controllers: how the model codes work

The Pool Line codes follow a logical pattern, and reading them correctly is the quickest way to order the right unit. The three digits describe the measurement and output set; the suffix describes how the probe meets the water.

• BL100 series — pH measurement with an integrated peristaltic dosing pump, for acid or alkali correction.
• BL101 series — ORP measurement with an integrated peristaltic pump, for chlorine or other oxidiser dosing.
• BL121 and BL122 — combined pH, ORP and temperature controllers; the BL122 adds Ethernet and Hanna Cloud connectivity for remote monitoring.
• BL131 and BL132 — pH, ORP and temperature controllers intended to drive external dosing pumps rather than an on-board one, with BL132 offering Hanna Cloud.
• Suffix -00, -10, -20 — the mounting style: a probe with no mounting kit, an in-line collar that taps straight into the pipework, or a panel with a flow cell through which a sample stream is routed.

Choose the in-line version where there is a suitable straight run of pipe and space for the probe body. Choose the panel and flow cell version where the probe needs to sit at eye level in a plant room, where pipework is awkward, or where a steady low-flow sample makes servicing easier. Both approaches need flow across the sensing tip while the unit is dosing.

PCA series analysers and their consumables

The PCA320-2 is a continuous analyser and controller that measures free chlorine and pH and dispenses reagent into a measuring cell to take each reading. Because it handles liquids on a cycle, it has genuine wear parts, and these are the items most often reordered:

• Reagent — HI70430 free chlorine liquid reagent, 0–5 mg/L range, supplied in 500 mL. Match the reagent to the parameter and range the analyser is configured for.
• Tubing — HI70483 and HI70484 complete tubing kits, the latter as a pack of three for sites that want spares on the shelf. Peristaltic and sample tubing stiffens and flattens with time, which shows up as drifting or low readings.
• Measuring cell — HI704871, the v.2 cell. Replace it when the optical path is scratched, clouded or stained beyond cleaning.
• Stir bar — HI70486, a pack of two magnetic stir bars; a worn or lost bar means the reagent is no longer mixed evenly.
• Solenoid valve — HI70489, 24 VAC / 50 Hz, for the sample handling circuit.

When ordering spares, work from the HI part number printed in the analyser manual or shown on the exploded view, and note the version of the cell already fitted. Cells and tubing sets are not interchangeable between unrelated instrument families.

Identifying the right part before ordering

Controllers and probes are easy to confuse across a site with several pools. A few checks save a return:

• Read the label on the controller housing for the full model code, including the suffix.
• Check the probe connector and body — an electrode for a flow cell is not always the same length as one for an in-line collar.
• Measure existing tubing outside diameter, wall thickness and length before replacing it with anything other than the matching kit.
• Note the supply voltage and frequency on the rating plate, particularly for solenoid valves and pumps.
• Record reagent lot and range so replacements match the instrument’s configured measuring range.

Dosing & control at PoolParthub.com

Here we list complete pH and ORP controllers with and without integrated peristaltic pumps, combined pH/ORP/temperature units with Ethernet and cloud options, chlorine and pH analysers, and the flow cells, in-line kits and electrodes that go with them. Alongside the instruments sit the parts that keep them reading correctly: reagents, tubing kits, measuring cells, stir bars and solenoid valves.

Stocking the consumables next to the hardware is deliberate. A dosing system only controls water as well as its sensors and its liquid handling allow, so the small, cheap, regularly replaced items matter more than the badge on the front panel. Filter by model or search the HI or BL code to go straight to the part that fits the unit already installed.