bluelab pH Pen - ± 0.1 pH Accurate, Durable Double Junction Probe, Waterproof & Floats, Auto Temperature Compensation, Easy Calibration - Made in NZ

2/18/25 Update: BlueLab reached out to me to resolve the issues I was having. They ended up sending me a new pH pen and shared some information on a few things worth considering. My new pen arrived and the storage cap was still moist with storage solution (this is a good thing). The new meter does work better than the original one, but I also suspect that my tap water has "low ionic content" which can cause pH readings to drift (this was also mentioned by BlueLab in their communications with me). I have found that the first readings of the day with the BlueLab pH pen can be a bit low when checking tapwater at my house. If I add nutrients to the water, the pH readings are much more definitive and easy to take. I believe this is to do with the ionic content. I experienced similar behavior with some other, cheaper pH meters. The BlueLab pen reads the calibration solutions quickly and accurately. My advice to anyone new to and/or serious about measuring pH, buy yourself some pH drops (General Hydroponics sells an affordable kit) so you can definitively measure your pH using a visual color matching method and compare to your meter readings. I found that the drops worked the same every single time without error or question or waiting and gave me more confidence in working with electronic pH meters. With some experimenting, I was able to figure out how to get repeatable and accurate readings from the BlueLab pH pen; Sometimes getting a reading of my tapwater that I am confident in takes a few tries. Why get a pen if drops work so well? The color shades when using drops are distinguishable between 6.0 and 6.5 for example, but identifying in between can be difficult to judge. The BlueLab pen gives me 0.1 resolution/accuracy that is needed when doing hydroponic gardening. Having both ways to check pH is ideal. I suspect that pH pens are generally not terribly expensive to manufacture, but it is costly to have a support team available to reach out to communicate with and help customers with their products. Ultimately, BlueLab came through with service, something that is rare these days. I appreciate this and have raised my rating to 5 stars. I really like the BlueLab pen cap, with the sponge that keeps storage solution on the bulb, and the rope used to connect it is also helpful when taking pH samples in a bucket. I do however, wish the the base of the cap was a bit wider so the pen could stand up on its own more reliably. I also wish the meter displayed down to 0.01, not because I need more accuracy, but because I want to see what the current measurement trend is doing (going up/down). The auto off timer also feels a bit short, but I suppose that is both good and bad. 1/10/25 (Original Review) I really wanted to like this expensive PH meter. Sadly It came with a dry probe so I soaked it as directed for 24 hours. Calibrated it 3x with Bluelab 4 and 7 solution but readings would drift for several minutes after each calibration. Tap water would measure at 6.4 right after calibration but leaving the pen in the same sample of tap water the reading would drift up to 7.5 after several minutes. It would never read the same value twice. Just a few minutes after calibration it would read the calibration solution several tenths lower than it should. I bought this expecting accuracy, not games. Returning.

This meter was a game changer for me, took a lot of stresses away since I live and die by accurate ph readings for growing them trees! High quality piece here that I (beyond) highly recommend this product! Easy to use on every level.. easy calibration with great directions to get you going. Speed and accuracy…love the fact it tells you when you got it calibrated correctly and also when it needs it again! 10 stars ⭐️⭐️⭐️⭐️⭐️⭐️⭐️⭐️⭐️⭐️

01-12-26 I have been using this Bluelab PH Pen since December 2023 and it is still working great, I dip it in clean water after every each use keep the tip wet so it doesn't dry out. I feel comfortable knowing the readings are true and my hydroponics are thriving.

The first one didn't work. But customer service replaced it quickly. The Second one works perfectly.

Seriously save your money. I keep seeing this pen routinely recommended for some reason as it was to me and decided to write a review to at least save some people some money. Stop buying this overpriced pen!! Its insane what this costs now. I admit I am bitter about it as I truly feel I got ripped off. I run two hydroponics gardens and two aquascaping fish tanks, both with pH sensitive shrimp species. I also run C02 to the fish tanks to help grow the plants, which lowers pH throughout the day. In fact, one of the ways to tell what your C02 concentration is by the relationship between pH of the water and KH (another test), but my point is simply that pH is important to me, and I am just mentioning it to prove I know a thing about water chemistry to say the least. This Bluelab pen is slow to respond at best, but totally way off at worse. Even after calibration it just can't be relied upon to give me accurate numbers. I use a cheapo pH meters and those give me consistent and accurate results. You can buy 5 of those and get better results than this pen gives! Better yet, at least on the aquariums I also use a basic API pH test kit, (where the water color changes based on PH) and again side by side the accuracy of that is hands down better than this pen. Is it possible I just got a bad pen? Maybe. I am aware of the "rules" on the pen - do not let it dry out, store the bulb in the proper solution, rinse it well before using, and pro tip - make sure to tap it so any air bubbles in the bulb float up and do not impact results. But even through all that, it calibrates fine, leads me to believe it will work and then goes wildly off. It cant be trusted. I do not like to write bad reviews but between the cost and my experience I am just hoping to help others. Go buy the $15 ones.

Bluelab pH pens are solid and perform well as long as they are cared for properly. My one gripe is that the instructions tell you to soak the pen for 24h in the provided storage solution, and a sachet with 20ml's of solution is in the box. In what world is 20ml's enough to pour into even the smallest of cups and provide a depth deep enough for the probe end to be covered? Completely ridiculous. I had to write this because I've purchased several of these pens over the years and every time I feel insulted by this cheapish move. How much can it cost to provide another 40ml's of KCl solution?

First let me say DO NOT be discouraged from the one star reviews. I can understand someone being upset if they buy a new pen and get one that’s broken but if that’s the case none of us would ever own anything. It is absolutely impossible to buy anything that doesn’t have a bad review because of something that in many cases that has absolutely nothing to do with how the product works, go look up anything you own and love and someone had an issue, seriously go look and see, I’ve tried it there is nothing I’ve found that everyone loves. This pen is awesome if you are a grower and ph is vital and you want to be a next level grower. I’ve had mine 2 years and when it stops working I will immediately get another one. It does take a small bit of little effort to add a few drops of storage solution that you have to buy extra but that last a long time and it’s worth it to me. You add it after each use to keep it hydrated. If it dries out the pen is not ruined like some say but you might have to recalibrate which is easy after your first few times, especially with the step by step YouTube videos available to watch while you’re doing it. Just remember there are a lot of lazy incompetent people out there that all they want to do is push a button and be done with it and expect everything to be instant and do nothing else. It all comes down to how important ph means to you and it is very important to me. This pen is accurate and it’s awesome and requires very little effort to maintain and it has helped me take my growing to the next level. It also works great with my pool to, way better than those test strips they have that do work but not quite as accurate as this ph pen. Thousands of top growers use this pen and depend on it, you see them on YouTube all the time using it. I happened to run across the reviews looking for something else and wanted to see what the hater’s were saying and now that I’ve used the Bluelab pen a couple of years I felt I could give a genuine review based on my experience with it. So, now it’s up to you to decide. Good luck!

Great pen.dont forget to let sit for 24 hrs