Horiba LAQUA DO220 Handheld Dissolved Oxygen Meter, Galvanic

DO220 is the dissolved-oxygen model of HORIBA’s LAQUA 200 handheld series. It reads oxygen in mg/L (ppm) and percent saturation from a galvanic probe with built-in temperature sensor, corrects for salinity and barometric pressure, and logs 1000 time-stamped results.

Dissolved oxygen without warm-up time

A galvanic oxygen probe generates its own signal from the oxygen reaching the cathode, so unlike a polarographic probe it does not have to be polarised before use. HORIBA lists the DO220 kits with a galvanic probe, and the manual describes the routine: calibrate in air, optionally add a zero point, and measure. The result is shown as concentration or as percent saturation, with the temperature underneath.

Two compensations are set from the keypad. Salinity can be entered from 0.0 to 40.0 ppt (default 0.0), which matters for estuarine, seawater and brine samples, and barometric pressure can be set from 10.0 to 200.0 kPa (default 101.3 kPa), which matters when you measure at altitude or compare readings from different days.

Features from the product page and manual

• Measures DO in mg/L with 0.01 resolution and in percent saturation with 0.1 % resolution.
• Up to two calibration points with the galvanic electrode: air (or saturation) and zero.
• Compensates salinity, temperature and atmospheric pressure.
• Real-time clock and date/time stamp, auto data log, auto stable, auto hold and real-time modes.
• Built-in electrode holder and foldable stand; IP67 shock-resistant, non-slip housing; 3-year meter warranty on the product page.

Technical specification

DO measurement data

Meter data

Kits on the product page

Cable length and series choice

Order DO220-K for bench, shoreline and tank-edge work, where a 2 m cable is enough, and DO220-K05 when the probe has to reach a deeper basin, a clarifier or a wet well from a walkway. The DO210 is the entry variant with a 500-record memory and no clock, but for sampling programmes that need a dated record the DO220 is the safer choice.

The DO220 is a single-parameter meter. If one instrument should also cover pH, conductivity or turbidity in the same visit, look at the multi-channel WQ-300 series or buy the matching 200 series meters side by side.

Calibration, measurement and probe storage

Set barometric pressure and salinity first, because both enter the calibration. For air calibration, hold the clean probe still in clean air out of rain and direct wind and do not hold the tip in your hand; wait for the stable mark and press ENT. The manual notes that 100 % in air is displayed as about 105 %, which is normal, as the reading in water is correct. For zero calibration dissolve 2 g sodium sulfite in 1000 mL deionised water.

In concentration mode calibrate from the high to the low standard: aerate fresh water for about two hours for the high point and stir at 1000 to 1500 rpm with the electrode at least 10 cm deep. The membrane is extremely thin; wipe it only with deionised water and a soft cloth. For long storage remove the DO tip, fit the shorting plug and rubber cap and keep it cool and dark with an oxygen scavenger.

Oxygen checks in wastewater, aquaculture and cooling systems

Dissolved oxygen is a routine parameter in aeration basins of wastewater plants, fish and shrimp farming, boiler feed and cooling-water checks, and environmental sampling of wadis and coastal water. Warm water holds less oxygen, so readings in summer will be low in percent and in mg/L; the salinity and pressure settings keep the numbers comparable between sites.

Selection and installation notes

Laboratory and field water analysis instruments are selected from the parameter, the range and the accuracy needed. Calibrate with fresh buffers or standards that bracket the expected readings, rinse the sensor between samples, keep the sensor wet and clean as the maker advises, record the temperature with every reading and replace sensors at the interval the manual states. Keep the calibration record with the results.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

Related instruments

The probe is part of the kit, and the PC and printer cables are listed above. PH220 and TB220 complete the 200 series for pH and turbidity.

Frequently asked questions

What type of oxygen probe does the DO220 use?

A galvanic probe with integrated temperature sensor: 9552-20D (2 m cable) or 9552-50D (5 m) in the kits.

What salinity range can be compensated?

0.0 to 40.0 ppt, set in the P1 DO setup.

Why does air calibration show about 105 %?

The manual explains that the electrode responds slightly differently to air than to water; readings in water are accurate.

How many records can the DO220 store?

1000, compared with 500 on the DO210.

Is Seven Star LLC a Horiba distributor?

No, we are an independent supplier in Muscat and supply Horiba items on request rather than acting as a Horiba channel partner.

Documents and quotation

For quotation, send your required quantity and destination. The Horiba instruction manual for DO220 is provided below the description on this page. Seven Star LLC works as an independent supplier from Muscat. Please compare code, ratings and approvals with the document before you place an order; see also the category listing.