GroStar GS4 pH/EC/ppm Tester

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.

Great quality, easy to use with well written instructions, and well packaged with a nice protective case.

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!

Perfectly calibrated out of the box. The pH meter is incredibly accurate and agrees with pH paper test strips! I had purchased another Apera meter (Apera Instruments AI311 PH60) thinking that I could use one of those cheap meters for EC but it was inaccurate and junk, wouldn't auto shut off and was a total waste of money and time. I had already wasted time and money on the cheap pH meters that were awful to calibrate, used expensive small button batteries, did not shut off automatically so it was 1 reading and new batteries if you don't shut them off. By mistake, I purchase 2 identical cheap pH meters and they won't even agree with each other for pH or EC and they don't agree with either of the Apera meters (both of the Apera meters agree perfectly on pH) or pH paper test strips. I don't have any thing to compare the EC meter with but from my experience with the pH portion, I would expect it is extremely precise and accurate. Would be nice if the GS4 came in a similar case to the PH60 instead of a cheap cardboard box that won't last.

Quality pocket tester! I like the simplified menus for the Grostar compared to the regular ones from Apera. I got the GS4 and it came with a hard case which is much appreciated, considering most picture reviews show just a cardboard box. Feels like it costs, built tough.

Simple straightforward tool. Not as advanced as the pc60 but for basic plant growth and gardening is definitely enough. My pc60-z has the app functionality which is great and it also reads in the hundredths which the grostar gs4 don’t but for all it’s worth it’s no needed. These serve well for the daily use and I can always check a nutrient solution against the pc60. I have two grostar one for indoor and one for outdoor. Thanks for the nice tools again apera

Recibí todo ok. Impecable el producto, aún no lo calibro, espero funcione todo bien.

While it is one of the more expensive options for testing these parameters, the GS4 is very high quality, easy to calibrate and east to use. Their customer service is also great. I accidentally broke the plastic clip/cap through my own carelessness and the sent me a new cap at no charge. They’ve also helped me rehab the device after I accidentally dropped it in the 5 gallon hydroponics bucket. I know, I need to be more careful.

Right out of the box (cardboard - not a nice case like my other Apera probe) I have found this a high quality tool. I tested pH4, 7 and 10 as well as two different EC1413 samples. The pH values were spot on and the ECs both read 1.3 which is acceptable as the ambient temperature was about 22C (the test fluid is calibrated for 25C). I have used Apera instruments before and they are expensive but trustable. You have to think how important it is to you that you are measuring your fluids exactly as planned or if saving money at this critical juncture by purchasing cheaper devices might be a false saving.

Funktional, präzise und einfach zu kalibrieren. Absolute Kaufempfehulng.

De momento lo voy usando y todo bien.

Leicht zu kalibrieren, präzise, einfach in der Handhabung.

Funciona perfecto, se siente que es de muy buena calidad. Tiene peso, no como otras marcas que se sienten liviano,