--- product_id: 514754304 title: "GroStar GS4 pH/EC/ppm Tester" price: "VT70862" currency: VUV in_stock: true reviews_count: 13 url: https://www.desertcart.vu/products/514754304-grostar-gs4-ph-ec-ppm-tester store_origin: VU region: Vanuatu --- # Fast 2-point calibration Replaceable double-junction probe Lab-grade precision GroStar GS4 pH/EC/ppm Tester **Price:** VT70862 **Availability:** βœ… In Stock ## Summary > 🌱 Grow Smarter, Not Harder: Precision Hydroponics in Your Palm ## Quick Answers - **What is this?** GroStar GS4 pH/EC/ppm Tester - **How much does it cost?** VT70862 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.vu](https://www.desertcart.vu/products/514754304-grostar-gs4-ph-ec-ppm-tester) ## Best For - Customers looking for quality international products ## Why This Product - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **Smart Maintenance Alerts:** Electrode condition indicator and calibration reminders keep your device peak-ready. - β€’ **Compact & Grower-Friendly:** Lightweight, ergonomic design fits perfectly in your hand and your workflow. - β€’ **Durability Meets Innovation:** Replaceable double-junction pH and titanium EC sensors built for longevity and accuracy. - β€’ **Precision that Powers Growth:** Lab-grade pH, EC, TDS, and temperature measurements tailored for hydroponic pros. - β€’ **Effortless Calibration in Under a Minute:** Intuitive 2-point calibration on a crisp HD backlit screenβ€”no guesswork, just results. ## Overview The Apera Instruments AI104G GroStar GS4 is a lab-grade 5-in-1 pen tester designed for hydroponic growers, measuring pH, EC, TDS (500ppm & 700ppm), and temperature with high accuracy. Featuring a replaceable double-junction pH/EC probe, fast 2-point calibration on an HD backlit screen, and smart maintenance alerts, it delivers reliable, professional-grade water quality testing in a compact, user-friendly design. ## Description Apera Instruments GroStar GS4 pH/EC/ppm Combo Pen Tester (Gen II) is a lab-grade multiparameter meter designed specifically for growers to easily manage crop success, featuring a replaceable pH/conductivity combo sensor and a grower-friendly workflow along with other intelligent functions and features that help reduce the guesswork and give you the confidence in every measurement. Review: Worth the cost - I bought a GS4 more than a year ago. I can't remember where I bought it so I can't pen down exactly when I bought it, but I suspect I've been using that first one for a couple of years at least. I bought this second one from desertcart as a back-up to the first one. A few months ago, because I am an expert at all things electronic, I put the batteries to the first one in backwards. In just a few seconds the whole thing heated rapidly. Very hot. Very rapidly. I happened to be holding it at the time, and I can attest to this. I rely on the results I get from the GS4, and I was relieved to see that once cooled, it calibrated as always and returned consistent results within tolerance. Your mileage may vary. I bought this second unit from desertcart as insurance against any further operator error. What spurred me to go ahead and get another just in case is that realized how much I depend on this pen. I spent way too much money trial-and-erroring my way to this meter. I suggest anyone who buys this pen to get qt bottles of standard solutions (4,7,10, 2.7), a qt of cleaning solution, and a pt of KCL. They're relatively cheap at that size, and cleaning/calibrating/storage becomes almost economical. This is a dependable, reliable instrument that's worth the trouble and expense of maintaining it. Review: High quality instrument - Great quality, easy to use with well written instructions, and well packaged with a nice protective case. ## Features - Lab-grade pH/EC/TDS meter designed specifically to meet growers' needs and habits - Measures pH, EC, 700ppm, 500ppm, and temperature with premium probe technologies, ensuring high accuracy and durability with minimal maintenance - Grower-friendly calibration workflow on an HD backlit screen allows you to finish 2-point calibration within a minute - Replaceable combo probe with double junction pH sensor and titanium EC sensor - Electrode condition indicator and calibration reminder function help you perform proper maintenance in a breeze ## Technical Specifications | Specification | Value | |---------------|-------| | Customer Reviews | 4.5 out of 5 stars 133 Reviews | ## Images ![GroStar GS4 pH/EC/ppm Tester - Image 1](https://m.media-amazon.com/images/I/61QciN9a4YL.jpg) ![GroStar GS4 pH/EC/ppm Tester - Image 2](https://m.media-amazon.com/images/I/61wHfmPlk9L.jpg) ![GroStar GS4 pH/EC/ppm Tester - Image 3](https://m.media-amazon.com/images/I/71UT803XjdL.jpg) ![GroStar GS4 pH/EC/ppm Tester - Image 4](https://m.media-amazon.com/images/I/71Cz3ZUm4lL.jpg) ![GroStar GS4 pH/EC/ppm Tester - Image 5](https://m.media-amazon.com/images/I/71a4HYma+lL.jpg) ## Available Options This product comes in different **Pattern, Style** options. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Worth the cost *by K***S on November 30, 2023* I bought a GS4 more than a year ago. I can't remember where I bought it so I can't pen down exactly when I bought it, but I suspect I've been using that first one for a couple of years at least. I bought this second one from Amazon as a back-up to the first one. A few months ago, because I am an expert at all things electronic, I put the batteries to the first one in backwards. In just a few seconds the whole thing heated rapidly. Very hot. Very rapidly. I happened to be holding it at the time, and I can attest to this. I rely on the results I get from the GS4, and I was relieved to see that once cooled, it calibrated as always and returned consistent results within tolerance. Your mileage may vary. I bought this second unit from Amazon as insurance against any further operator error. What spurred me to go ahead and get another just in case is that realized how much I depend on this pen. I spent way too much money trial-and-erroring my way to this meter. I suggest anyone who buys this pen to get qt bottles of standard solutions (4,7,10, 2.7), a qt of cleaning solution, and a pt of KCL. They're relatively cheap at that size, and cleaning/calibrating/storage becomes almost economical. This is a dependable, reliable instrument that's worth the trouble and expense of maintaining it. ### ⭐⭐⭐⭐⭐ High quality instrument *by S***H on March 31, 2026* Great quality, easy to use with well written instructions, and well packaged with a nice protective case. ### ⭐⭐⭐⭐⭐ Better alternative to the Overpriced Bluelab Onepen. *by S***B on February 24, 2026* I initially went with a the overpriced Bluelab OnePen, and decided to go with the Apera. This PH pen works faster than the Bluelab for half the price. I do a three point calibration and it is accurate. Worth it! ## Frequently Bought Together - Apera Instruments AI104G GroStar Series GS4 pH/EC/500ppm/700ppm Combo 5-in-1 Pen Tester Kit with Replaceable Double-Junction pH/EC Probe for Hydroponics Water Quality Testing, Gen II - Apera Instruments pH Probe Electrode Sensor Care Maintenance Kit, Including pH 4/7/10 buffers, 3M KCL Soaking Solution, Probe Cleaning Solution, a CalPod Solution Organizer (AI1170) - Apera Instruments 3M KCL Storage Soaking Solution (8 oz.) for pH and ORP Electrodes --- ## Why Shop on Desertcart? - πŸ›’ **Trusted by 1.3+ Million Shoppers** β€” Serving international shoppers since 2016 - 🌍 **Shop Globally** β€” Access 737+ million products across 21 categories - πŸ’° **No Hidden Fees** β€” All customs, duties, and taxes included in the price - πŸ”„ **15-Day Free Returns** β€” Hassle-free returns (30 days for PRO members) - πŸ”’ **Secure Payments** β€” Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** β€” Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.vu/products/514754304-grostar-gs4-ph-ec-ppm-tester](https://www.desertcart.vu/products/514754304-grostar-gs4-ph-ec-ppm-tester) --- *Product available on Desertcart Vanuatu* *Store origin: VU* *Last updated: 2026-06-05*