Currently unavailable.
We don't know when or if this item will be back in stock.

Image Unavailable

Image not available for
Color:

To view this video download Flash Player

General Hydroponics Ph 4.01 & Ph 7.0 Calibration Solution Kit, 8 oz

Visit the General Hydroponics Store

4.6 1,158 ratings

Currently unavailable.
We don't know when or if this item will be back in stock.

Brief content visible, double tap to read full content.

Full content visible, double tap to read brief content.

Size: Pint

Pint

Updated other options based on this selection

2 Bottles - 1 Each Of Ph 4.01 & Ph 7.0 Calibration Solution
Highest Quality Electronic Meter Reference Solutions
Each Batch Is Checked To Ensure Calibration
No Assembly Required

Customer ratings by feature

Easy to use

4.4

Accuracy

4.0

Value for money

3.8

See all reviews

Brief content visible, double tap to read full content.

Full content visible, double tap to read brief content.

Videos for similar products

From the manufacturer

About Us

At General Hydroponics, growing is at the heart of who we are and everything we do. We live it and breathe it. The story of General Hydroponics spans more than 4 decades — with humble origins as a garage-based startup in Berkeley, CA and growing in hydroponic plant nutrition that it is today. A community built by those who wake up every day with the grit to create something extraordinary — and to do it on their terms. We take inspiration from those who refuse to follow the rules. We believe in the underdogs. The rebels. The nonconformists. Because that’s exactly how we got our start.

Product Description

General Hydroponics uses the highest-quality reference solutions, allowing growers to calibrate many popular brands of PH, EC and TDS meters (NaCl scale or the 442 scale). General Hydroponics technicians check each batch to ensure that our solutions are precisely calibrated and yield reliable readings each time they are used.

Product information

Product Dimensions

8 x 4 x 4 inches

Item Weight

1 pounds

Manufacturer

General Hydroponics

ASIN

B017H73794

Item model number

GL56722015.030

Customer Reviews

4.6 1,158 ratings

4.6 out of 5 stars

Best Sellers Rank

#125,793 in Industrial & Scientific (See Top 100 in Industrial & Scientific)
#70 in Chemical Buffers

Is Discontinued By Manufacturer

Feedback

Would you like to tell us about a lower price?

Important information

To report an issue with this product or seller, click here.

Looking for specific info?

Customer reviews

4.6 out of 5

1,158 global ratings

How customer reviews and ratings work

Reviews with images

See all photos

Sort reviews by

Top reviews from the United States

There was a problem filtering reviews right now. Please try again later.

Devin R. Olsen

Works great, and the colors are a big plus to me.

Reviewed in the United States on April 3, 2017

Size: PintVerified Purchase

Great calibration solution so far. Arrived on time, colors are a huge help and seems to be very accurate as advertised.
Best advice I can give others with this is that you don't EVER want to dip your devices directly into these bottles to calibrate, as you will instantly contaminate the solutions and will have wasted your money (no matter how hard you try to avoid it). Instead ALWAYS pour a little amount of each solution into separate containers (shot glasses work well heh) and dip said device(s) into these separate containers to avoid contamination or original solution sources.

General Hydroponics, if you are listening to this, the only design change I would like to see on this produce is to maybe add a tiny dent to the lip of the bottles cap. The surface tension of the bottles material creates a stream of solution that does not pour out well, and a little dent creates a spout effect or pouring much easier and the user's experience with product much nicer.

32 people found this helpful

Helpful

Jonathan

Very good for ph meter

Reviewed in the United States on August 24, 2022

Size: PintVerified Purchase

Very good it calibrated ph meter quick

Helpful

Mark King

EXCELLENT FOR PH PEN CALIBRATION

Reviewed in the United States on May 2, 2016

Verified Purchase

I use these solutions to calibrate my PH pen.

The lids of the bottles are deep enough, I just put solution in the lid and insert my PH pen to get a reading, after it settles, I turn the calibration screw on the PH pen to match the fluid I'm testing. Be sure to rinse the pen well in distilled water before moving to the other PH solution.

I love the size, price and reliability of these solutions. I'd definitely buy again.

Packed well and arrived fast.

3 people found this helpful

Helpful

Charles Gardner

Works well

Reviewed in the United States on April 30, 2022

Size: PintVerified Purchase

Consistent and accurate, will buy again

Helpful

Guinness

Just an FYI for Blue Labs PH Pen Owners.

Reviewed in the United States on May 24, 2019

Size: PintVerified Purchase

For those who have a bluelabs PH pen and are looking for a cheaper alternative to their calibration solution and found this, do not use it. There's something bluelabs puts in there solution so you cannot use competitors to calibrate your device. Again, I don't blame GH for this, but it's something I think people need to know before ordering

37 people found this helpful

Helpful

jesse may

Works,

Reviewed in the United States on April 7, 2020

Size: PintVerified Purchase

Trust the solution. Have an HM digital PH200. Just got the solution today. My meter has autocalibrate, so it automatically audjusts to the nearest value of calibration solution. So if you put it in a 7 solution and calibrate it is supposed to automatically go to 7. With this solution it is autocalibrating the green solution that is supposed to be 7 to 10 and the pink that is supposed to be 4 to 7. My probe was totally off before, messing up the auto calibrate.

Helpful

Amazon Customer

Need to keep your calibration right for your pH

Reviewed in the United States on September 3, 2022

Size: PintVerified Purchase

easy to use

Helpful

Brian Lees

good enough for those who care.

Reviewed in the United States on September 19, 2015

Verified Purchase

got this for a cheap pH meter. didn't know they have a short life span of a few months, but I dont really care, they'll get me "close enough" that I wont have to use litmus paper or the stupid drop bottle ever again. next time i'll be getting an oakten meter.

it works. the bottle tops are just big enough to fit my Etekcity yellow china pH meter in, as long as its mostly full.

obviously you don't want to just dip the thing in the bottle like I do, you want to separate it in another container, to keep the solution as pure as possible.

for my meter, its only a single point calibration, I usually use both solutions to see how far from each I am. then I calculate the difference between the 2, and will divide the difference between the 2, that way i'm as accurate as I can be on both ends of the scale. I also tend to run my pH a bit higher than normal (target for me is 5.8-6.0) which gives me a good half point of buffer in both directions up or down. I'm all about the keeping it simple without being too inaccurate.

IMO, get as small of a bottle as you can get away with for about 2-3 months worth of calibrations, as this stuff goes bad apparently. better meters usually require less calibrations. my meter I either check every other day, to every week. its usually within .10.

5 people found this helpful

Helpful

Top reviews from other countries

Johnny

A+

Reviewed in Canada on May 17, 2019

Size: QuartVerified Purchase

Just what I needed to set my ph pen . Should last along time and it being two different colors makes it easy to remember what's what .

One person found this helpful

Guy That Buys

Works

Reviewed in Canada on May 25, 2020

Size: QuartVerified Purchase

Works as intended.
Both are bang on with their pH rating.

Tristan

Perfect

Reviewed in Canada on August 30, 2018

Size: PintVerified Purchase

Works just the way it should... lasts forever if you use small amounts each time you calibrate. Has kept my meter running accurately! Thanks.

One person found this helpful

Greg B

THIS IS NOT PH UP/DOWN!

Reviewed in Canada on April 9, 2019

Size: PintVerified Purchase

Just a heads up. Does what it says on the tin. I still gave 5 star because its not their fault I impulse shop while tipsy.

9 people found this helpful

Young

Great way to start with these for ur ph pen cal

Reviewed in Canada on May 19, 2019

Size: PintVerified Purchase

For the 7.0 not accurate other than that is great product no complaint

See more reviews

Image Unavailable

General Hydroponics Ph 4.01 & Ph 7.0 Calibration Solution Kit, 8 oz