1
2
3
4
Click on image to zoom
Bluelab pH Pen, Waterproof - Bluelab - Happy Hydro Bluelab pH Pen, Waterproof - Bluelab - Happy Hydro Bluelab pH Pen, Waterproof - Bluelab - Happy Hydro Bluelab pH Pen, Waterproof - Bluelab - Happy Hydro

Bluelab pH Pen, Waterproof

Bluelab
Price:
$99.95
img 1

Free Shipping Over $49

img 2

Financing
Available Here

img 3

Discreet Packaging

img 4

Have a Question?
716-217-0353

Description

Know your pH in seconds with a pen that thrives in the grow room

The Bluelab pH Pen reads pH from 0.0 to 14.0 at 0.1 resolution and shows solution temperature on the same backlit screen. It is fully waterproof (not just splash-resistant) and floats if it lands in your reservoir. Bluelab builds it in New Zealand with a double-junction probe for longer life in nutrient-heavy solutions, and it ships with pH 4.0, pH 7.0, and KCl storage solution so you can calibrate and start measuring the same day.

Fully waterproof 1-year warranty Made in New Zealand
Free shipping on orders over $49
30-day returns on all orders
Serving growers since 2006
Gallery
See it in action
Side by side
Cheap pH pens vs. the Bluelab pH Pen
Budget pH pens
  • Single-junction probes clog fast in nutrient solutions
  • Drift out of calibration within days
  • Water-resistant at best, dead after one drop in the reservoir
  • No calibration reminder, so you forget and run on bad data
  • No temperature compensation, readings shift with heat
  • Calibration solutions sold separately, adding $10+ on day one
Bluelab pH Pen
  • Double-junction probe resists contamination from nutrients
  • 2-point calibration (pH 4.0 and 7.0) holds accuracy to ±0.1 pH
  • Fully waterproof and floats, built for daily reservoir use
  • 30-day calibration reminder built into the firmware
  • Automatic temperature compensation adjusts readings in real time
  • pH 4.0, pH 7.0, and KCl storage solution included in the box
Key features
What makes this pen worth keeping

Double-junction pH probe ±0.1 pH

Two reference junctions instead of one. The outer junction takes the beating from nutrient salts so the inner junction stays clean, which means stable readings for longer before the probe wears out.

Waterproof and floats

Not splash-rated, fully waterproof. If it slips into the reservoir, it floats on the surface instead of sinking to the bottom.

Automatic temperature compensation

pH readings shift with temperature. The pen measures solution temp (0 to 50°C) and corrects the pH value automatically, so a reading from a warm reservoir is just as reliable as one from a cool mixing bucket.

Backlit LCD with hold function

The screen lights up for reading in dim grow rooms. Press the hold button to lock the display so you can pull the pen out and read at eye level.

30-day calibration reminder

A built-in timer tracks the days since your last calibration and alerts you when it is time to recalibrate. No guessing, no forgetting.

Auto-off and low battery warning

The pen shuts itself off after inactivity to preserve the single AAA battery. A low-battery icon appears before it dies so you are never caught mid-reading.

Specs
Technical details
pH Range
0.0 to 14.0 pH
Accuracy
±0.1 pH (at 25°C)
Temp Range
0 to 50°C / 32 to 122°F
Resolution
0.1 pH, 1°C / 1°F
Calibration
2-point (pH 7.0 and pH 4.0)
Power
1x AAA alkaline (included)
Origin
Designed and built in New Zealand
Warranty
1-year limited (proof of purchase required)

How to set up and use your pH Pen

1

Hydrate the probe

Remove the storage cap and soak the probe tip in the included KCl storage solution for 24 hours before first use. This activates the glass membrane so it can read pH accurately.

2

Calibrate with two solutions

Dip the probe in the pH 7.0 sachet, press the calibration button, then repeat in the pH 4.0 sachet. A confirmation indicator on screen tells you the calibration succeeded.

3

Take your reading

Submerge the probe in your nutrient solution or reservoir and wait for the display to stabilize. The reading shows pH and temperature simultaneously on the backlit screen.

4

Rinse, store, repeat

After each use, rinse the probe tip in clean water, then replace the storage cap with a few drops of KCl solution inside. This keeps the probe hydrated and extends its working life.

In the box
Everything you need to calibrate and start measuring
Included with every pen
  • Bluelab pH Pen (waterproof)
  • pH 7.0 calibration solution sachet
  • pH 4.0 calibration solution sachet
  • KCl probe storage solution
  • 1x AAA battery (installed)
  • Quick-start guide
Recommended add-ons
  • Bluelab Conductivity Pen: Measures EC/PPM so you can check nutrient strength alongside pH
  • Bluelab Probe Care Kit (pH): Extra calibration sachets, KCl solution, and cleaning tools for ongoing maintenance
  • Bluelab KCl Storage Solution (250ml): Larger bottle for long-term probe storage between uses
Not sure if you need the Conductivity Pen too? If you are hand-mixing nutrients, yes. pH tells you whether plants can access food, EC tells you how much food is there. Call us and we can walk you through it: 716-217-0353 / help@happyhydro.com
Questions
Frequently asked questions
The only setup is hydrating the probe in KCl solution for 24 hours (comes in the box), then doing a two-button calibration with the included pH 4.0 and 7.0 sachets. The pen shows a confirmation icon when calibration is successful, so you know you did it right. After that, you just dip and read.
This pen is designed for testing liquid solutions: reservoirs, runoff, tap water, or nutrient mixes. If you need to test directly in soil, coco, or other solid media, Bluelab makes a separate Soil pH Pen with a flat-tip probe designed for that. This standard pH Pen is the right choice if you are checking water or nutrient solution before you pour it.
Bluelab recommends calibrating once every 30 days, and the pen has a built-in reminder that tracks it for you. Each calibration takes about two minutes. You will eventually run out of the included sachets, so picking up a Bluelab Probe Care Kit or extra sachets is a good idea for the long run.
The probe on the standard pH Pen is not replaceable. With proper care (rinsing after use, storing in KCl solution, recalibrating monthly), most growers get 1 to 2 years of reliable use. If you want a replaceable-probe option, Bluelab recently released the pH PenPlus, which accepts a swap-in probe when the original wears out.
Yes. The probe tip is a glass membrane that must stay hydrated to read accurately. If the probe dries out, readings drift and eventually the probe fails permanently. Add a few drops of KCl solution inside the storage cap and keep it on the pen between uses. Never store the probe dry or in plain water.
The Bluelab pH Pen reads to 0.1 pH resolution with ±0.1 accuracy at 25°C. For hydroponic nutrient management, where your target range is typically 5.5 to 6.5, that level of precision is more than enough. Lab-grade meters read to 0.01 pH, but that extra decimal point rarely changes a grower's decision.
If you receive a defective or damaged unit, email us a photo at help@happyhydro.com and we'll make it right immediately: replacement or refund, your call. For change-of-mind returns, we accept returns within 30 days for items in new, resalable condition. If you're not sure whether this product is right for your setup, call us first at 716-217-0353. We'd rather answer your questions before you order.
Happy Hydro has been selling growing equipment since 2006. We've carried Bluelab for years because the systems work great and customers who buy them leave happy. Have questions before you order? Call 716-217-0353 or email help@happyhydro.com. We're easy to reach and happy to help!

Your Happy Hydro Shipping Experience

We ship fast from Buffalo, NY. Most orders land at your door in 3-5 business days. Free standard shipping on orders $49+, plain-box packaging, and real humans ready to help if anything goes sideways.

Free shipping on orders over $49
Plain-box discreet packaging
Serving growers since 2006
What to expect
When you order from Happy Hydro

Fast & Free on Orders $49+

Free standard shipping to the lower 48. Most orders ship same or next business day from our Buffalo, NY warehouse via UPS Ground or USPS Ground Advantage. Expedited options available at checkout.
* Soils may incur added fees for Western US delivery
* Some products ship direct from the vendor's warehouse to keep prices lower and get your order there faster

World-Class Customer Care

Our grower support team is here 10 am-4 pm EST, Monday-Friday. Call 716-217-0353 or email help@happyhydro.com.

Discreet & Secure Packaging

Every order ships in a plain brown box with no branding or logos. Your purchase stays 100% private. We can also ship to your local UPS Store on request.

Specs
Shipping details at a glance
Delivery time
3-5 business days
Default carrier
UPS Ground or USPS
Signature required
Orders over $500 only
Free shipping threshold
$49+ to the lower 48
International
Canada only Email help@happyhydro.com your address & a screenshot of your cart for a quote
Returns
30 days on most orders Exceptions apply — orders over $400, multi-box shipments, and some vendor items may incur return shipping charges. Full policy
Questions
Frequently asked questions
Shipping
Check the order confirmation sent to your email or phone after checkout — it includes a tracking link. If you use the Shop App, you can track your order there too.
Most orders arrive in 3-5 business days. Expedited options (2-day, overnight) are available at checkout if you need it sooner.
Signature is only required on orders over $500. For added privacy, we can ship to your local UPS Store so you pick it up on your own schedule — just ask.
We default to UPS Ground or USPS Ground Advantage. Select an expedited option at checkout and we'll use the appropriate carrier for that service.
  • P.O. boxes: Yes, for small and lightweight items.
  • International: Canada only. Email help@happyhydro.com your address and a screenshot of your cart for a shipping quote.
  • APO/FPO: Not currently available.
For Canadian orders, import duties and taxes are the buyer's responsibility. You'll complete payment using your tracking number at UPS.com when your package arrives.
Title and risk of loss pass to you once we hand off to the carrier, but that doesn't mean we leave you hanging. Email help@happyhydro.com and we'll work overtime to track it down and make it right.
Payment
We accept credit/debit cards, PayPal, Coinbase, and Happy Hydro gift cards. Your card is charged immediately at checkout.
Double-check your billing address and card number. For larger purchases, your bank may have flagged it — a quick call to authorize the transaction usually sorts it out.
Promotions
Enter your code in the "Promo code" box at checkout and click Apply. One code per order, but you can combine a gift card with a promo code if you have both.
Subscribe to our mailing list for exclusive discounts and early access to sales. You can sign up at the bottom of any page on our site.
Returns & Cancellations
Email help@happyhydro.com within 30 days of delivery and we'll get you a refund or replacement, your choice. Items must be in original packaging with all parts in resalable condition. Multi-light orders, grow tents, orders over $500, and multi-box shipments may incur return shipping charges. AK, HI, and international buyers are responsible for return and warranty shipping. Some vendor-specific policies may apply — check the product page for details.
Refunds are processed through Shopify within 10 business days. Most customers see the credit back in about 5 days.
Reply to your order confirmation email or email help@happyhydro.com as soon as possible. Canceled orders may incur a processing fee depending on your payment method:
  • Credit/debit card: 2.9%
  • PayPal or Venmo: 3.5%
  • International PayPal: 4.0%
  • American Express: 4.1%
  • Shop Pay Installments / PayTomorrow: 6.5%
Support & Policies
Call or chat with our grower support team at 716-217-0353, Monday-Friday 10 am-4 pm EST. You can also email help@happyhydro.com any time and we'll get back to you quickly.
Your privacy matters to us. Read our full policy at happyhydro.com/pages/privacy-policy.
Why Buy From Happy Hydro

Why Buy From Happy Hydro

Happy Hydro began as a pipe dream in a garage and has grown into something built almost entirely on word of mouth and repeat customers. Rather than focusing on raising margins and obsessing over profits, we've always believed that the right combination of competitive prices, superior products, and world-class customer service speaks for itself. Our philosophy will never change: when you're happy, we're happy.

Our commitment
What you can expect from Happy Hydro

Real People, Real Growers

Our grower support team isn't a call center. They know the products because they're passionate about growing. Reach us Monday-Friday, 10 am-4 pm EST at 716-217-0353 or help@happyhydro.com, before you order or after.

Hand-Picked by Growers, for Growers

Every brand we carry was chosen by our founders because it performs. We only stock premium brands we believe in, and every item is inspected before it leaves our warehouse.

Fair Prices and Free Shipping

We work hard to keep our prices as low as manufacturers allow, and we include free shipping on orders over $49 so there are no surprises at checkout. Find a lower price anywhere and we'll match it.

Authorized for Every Brand We Carry

We're an authorized dealer for every manufacturer on our site. That means you get the full manufacturer's warranty on every purchase. No grey market, no expired stock.

30-Day Returns on Most Orders

Hard to commit to a product you haven't tried. Return most items within 30 days in original condition and we'll take care of it. Read the full policy.

Secure Shopping, Private Data

Every transaction is SSL encrypted. We don't store payment information and we will never sell your data to anyone, ever.

Volume and Commercial Pricing

If you're a commercial grower or putting together a large order, reach out before you buy. We have pricing available that we can't advertise publicly. Call 716-217-0353 or email help@happyhydro.com and we'll take care of you.

Frequently Bought Together

Product Reviews

Payment & Security

American Express Apple Pay Diners Club Discover Google Pay Mastercard PayPal Shop Pay Visa

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

You may also like

Recently viewed