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Bluelab Guardian pH, cF and Temperature Monitor

From £259.95
In stock
Grouped product items
Bluelab Guardian pH, cF and Temperature Monitor Code: 2035
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Target Temperature: 18 – 21oC
Target CF: Depends on your water hardness and stage of growth
Target pH: 5.5 – 6.5 (ideally 6)

Monitor your nutrient pH, CF & temperature 24 hours a day with Bluelab Guardian. All readings are live!

You’ll know exactly when to tweak your feed - Simply set your target pH, CF & temperature. Any readings that are off targets will flash!

Your settings are saved if power is lost. Better yert, no calibration’s needed for your CF or temperature. To calibrate your pH, there’s one simple button. 

Get your temperature, pH and CF right to boost nutrient uptakeenhance growth and improve root health.

Mount it on a wall or hang it on a support bar, it’s up to you. Either way, it’s easy to set and easy to read with simple push buttons and ultra large LCD display. A quick look at the monitor is all it takes.

• Monitors CF, pH & nutrient temperature
• 12 month warranty included
• Large LCD display that’s plant safe
• Adjustable brightness
• Visual alarm for high and low readings
• High tolerance to RF/electronic interference
• No calibration needed for conductivity or temperature
• Water resistant design
• Simple push button pH calibration
• Replaceable double junction pH probe
• Settings saved if power is lost

Your nutrient pH, CF and temperature can have a major impact on growth.


It your temperature is too high, your oxygen level drops. As a result, nutrient uptake slows and root diseases can thrive.


To make matters worse, when your feed is warm, algae grows, which lowers your oxygen level further. For best results, keep your feed to 18oC – 21oC.


At the wrong pH, some nutrients in your feed cannot be absorbed by your plants. For maximum absorption, keep your pH between 5.5 and 6.5 (6 is the ideal).


Your CF/EC (nutrient strength) tells you how strong your feed is. The exact strength you need will depend on how hard your water is, but it should generally be 6 – 12 CF (young plants), 10 – 16 CF (establishing plants) & 15 – 20 CF (mature plants).

• Bluelab Guardian Monitor
• Bluelab pH Probe with storage cap
• Bluelab Conductivity/Temperature Probe
• Bluelab pH Probe holder with suction cup
• 5V DC power supply
• North American plug adaptor
• 7 NZ / Australian plug adaptor
• UK plug adaptor
• European plug adaptor
• 4 x mounting fasteners
• 2 x cable ties
• pH 7.0, pH 4.0 and EC 2.77 single use calibration solution sachets
• Bluelab Guardian Monitor Getting Started Card

Mount your Guardian to a wall, or hang it on a support bar near to your nutrient reservoir and main socket.

Connect it to the plug

Submerge the two probes into your nutrient solution

Switch on the power for live and continuous readings


• Let the pH probe tip dry. IF IT DRIES, IT DIES!
• Bend the probe; this will break its internal glass tube
• Knock the probe; this will break its internal glass tube or external glass bulb.
• Plunge a cold pH probe into a hot liquid - sudden temperature changes can crack the glass and permanently damage the probe.
• Immerse in oils, proteins or suspended solids that will leave a coating on the glass bulb
• Kink or bend the lead sharply.
• Try to lengthen the lead on the pH probe.
• Wet the BNC connector at the end of the lead.

Always remove pH probe storage cap before use

1. Grip the top of the cap and gently twist the base one rotation clockwise to loosen slightly.
2. Next slowly slide the cap off the pH probe. DO NOT completely remove the base of the cap from the top of the cap.
3. Store the storage cap in a safe place.

Storing the pH probe

When storing the pH probe, the pH probe tip must be kept moist.

To prepare the pH probe for storage, add enough Bluelab pH Probe KCL Storage Solution to the storage cap so the probe tip is covered.

Then replace the cap and store in a secure place.

DO NOT use RO (Reverse Osmosis), Distilled or De-ionized water.

Pure water changes the chemistry in the reference, causing the probe to die.

If the pH probe has been accidentally allowed to dry out.

You should ‘hydrate’ it for 24 hours in KCL storage solution (never use RO, Distilled or De-ionized water).

Following this, carry out a calibration to check if the probe has already suffered permanent damage.



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