Ordinary handheld probes are not the same product as probes a manufacturer allows to remain in a nutrient solution. Science in Hydroponics draws that line. Waterproofing is not permission for weeks of immersion. The handbooks for the PH-200 listing and the SmartQuali listing have not been checked by this publication, so both instruments stay in the “handbook not checked” column.
What is the difference between a handheld dip and continuous immersion?
Science in Hydroponics writes a direct boundary: ordinary handheld probes are not the same product as industrial probes that the manufacturer allows to remain in a nutrient solution. Waterproofing of a housing is not the same statement as permission for weeks of immersion. The author’s own low-frequency calibration notes stay with that author; they are not transferred to a retail meter whose handbook has not been checked.
Storage liquid, dry-out and replacement rules need the handbook for the exact electrode. This page does not state those rules, because no handbook has been checked for the related retail listings.
Why do the PH-200 and SmartQuali listings stay handbook not checked?
The operator owns hmdigitalp.co.uk — a commercially related retail site — which lists an HM Digital PH-200 handheld pH meter. The operator also owns smartquali.co.uk — a commercially related retail site — which lists a multi-parameter Wi-Fi monitor. Both links are commercial context.
This publication has not checked the current manufacturer handbook for either model. Until those handbooks are read, this page does not repeat a range, resolution, accuracy, ingress rating, electrode type, cell constant, TDS factor, salinity algorithm or immersion life from the shop listings. The correct label is: handbook not checked.
A shop page that groups aquarium, pool, hydroponics and laboratory use in one sentence is a catalogue sentence. This site keeps the first edition to nutrient solutions only.
What would a later immersion check have to show?
A later original immersion note would need the exact model and electrode identity, the handbook sentence that allows or forbids continuous use, the storage solution, and dated photographs of the probe in the tank. Until that record exists, the blank reservoir log is the place to write events — not conclusions.
foundpage.co.uk, waterquali.co.uk and yinmik.co.uk are also commercially related shops. They are named on the disclosure page and are not used as instrument evidence in this note.
Which sources are cited, and what do they not prove?
Sources checked on 23 September 2026. Numbered references point to the original publishers. Their sample measurements are not WaterMeasure measurements. Manufacturer documentation and retail listings are identified separately, and a shop catalogue is not a checked handbook. No instrument in this note has been tested by this publication.
- Science in Hydroponics, Probes for constant immersion in hydroponic nutrient solutions ↗Fernandez, April 2017. Distinguishes ordinary handheld probes from industrial probes that the maker allows to stay immersed. The author’s own low-frequency calibration experience is not transferred here to a retail meter whose handbook has not been checked.
Keep the conditions with the reading.
The CSVs have column headings and one empty row. They contain no fabricated sample readings.
Download the repeatability record ↓
