General Hydroponics pH Control Kit

General Hydroponics pH Control Kit

SKU #: HGC722080
General Hydroponics Brand Product

Availability: In stock

Lead time: Ships in 24-48 Hours


The Easiest Way to Maintain a Properly Balanced Nutrient Solution For Ideal Plant Growth!

General Hydroponics pH Test Kits make pH testing easy. Fill a test-tube halfway with nutrient, add a few drops of pH Test Indicator (Use 3 drops per 5mL of solution), and observe the coloration of the liquid in the test vial. Many experienced growers prefer our pH Test Kit to expensive electronic meters because it is reliable and easy to use.

pH Control is essential for simulating vigorous plant growth. Nutrient solution pH that is too high (basic) or too low (acidic), cannot be properly absorbed by plants. Incorrect nutrient solution pH can cause issues such as slow growth, sick plants and low yields.

The pH scale measures acidity or alkalinity on a scale of 0 - 14. Below 7.0, the pH is acidic. Above 7.0, the pH is alkaline (basic). 7.0 is "neutral". The best pH for plant growth is generally in the range of 5.5 - 6.5 -- slightly acidic.

There are several causes for incorrect nutrient solution pH. Tap after used to mix nutrient solution often contains minerals and impurities that can affect pH of your nutrient solution. Rapidly growing plants consume different nutrients at different rates, thus altering the solution's original pH. Growing media such as rockwool or construction grade aggregate (pea gravel and shale) can dissolve slowly, greatly affecting the nutrient pH and causing to rise or fall significantly.

By maintaining nutrient solution pH within the range of 5.5 - 6.5, you can assure your crop "maximum availability" of all nutrient minerals. This will give you higher growth rates, higher yields, and healthier plants -- healthy plants are more resistant to insect infestation and disease.

Test adjust nutrient solution pH after mixing fresh hydroponic solution (or fertilizer for soil cultivation) and again every few days to maintain correct pH. For best results, discard and replace hydroponic solution regularity.

Directions: Fill test tube halfway with nutrient solution. Add 3-5 drops of pH test indicator and tap on vial to mix contents. Compare color in vial to pH color chart to determine nutrient ph.

  • Yellow to Yellowish-Green - Indicates the ideal pH range for plant growth (5.5-6.5).

  • Orange or Red - Indicates the pH is too low (below 5.5), add pH UP (Base) to raise nutrient pH.

  • Blue-Green or Blue - Indicates the pH is too high (above 6.5), add pH DOWN (Acid) to lower nutrient pH.

Repeat to verify the nutrient pH is now within the correct range (5.5 - 6.5.)

Tech Specs


BrandGeneral Hydroponics
Weight (lb.)1.6
Height (in.)9.2
Prop 65No
Lead TimeShips in 24-48 Hours
Length (in.)2.8
Width (in.)5.6
UL ListedNo

General Hydroponics pH Control Kit Videos

Product Q&A

General Hydroponics pH Control Kit Questions & Answers

What is pH?
pH is the measure of acidity/alkalinity of a solution.

Can you explain this in a little more detail?
Specifically, pH is a measure of the hydronium ion H3O+. It is based on a logarithmic scale from 0 to 14. "Pure" water has a pH of 7.0. If the pH is less than 7, the solution is acid. If the pH is greater than 7 it is alkaline. Because the scale is logarithmic and not linear, a pH of 6 indicates ten times more H protons than a pH of 7, and a pH of 5 indicates 10 times more protons than a pH of 6.

What pH is best for growing plants hydroponically?
The ideal pH range for most hydroponic crops is between 5.5 and 6.5.

How does pH level affect plant growth?
pH is important because it affects availability and absorption of several of the 16 atomic elements needed for plant growth. Maximum absorption of these elements is found at pH readings 5.5 to 6.5. When pH falls below this range many of the macro elements (N, P, K, etc) have less availability, and absorption of the micro nutrients can reach toxic levels.

How do you change the pH?
pH is adjusted by using an acid to lower it or an alkali to raise it. General Hydroponics' pH Down and pH Up are designed for this purpose. Many acids and alkalis are extremely corrosive and dangerous, so care should be used if you are not using a product labeled for hydroponic use.

What if I can not get any pH Down, and my system is running high?
Short-term solutions include citric acid (which degrades in solution) or sulfuric acid made for car batteries. Make sure this does not include any lead, and be very careful with this acid. Vinegar will also work, but generally, the effects are short term.

How often should I check my pH level?
When first starting out it is a good idea to measure the pH of your water every day, until you get a feel for your system. Measure your water and then add your nutrients. Within an hour check the pH and adjust accordingly. Repeat this process until pH stabilizes. The liquid Flora Series has special pH buffers to help maintain a desirable pH. It is a good idea to note how much water, nutrients and pH modifiers are needed to obtain the desired values. After several "start- ups" you can generally get a feel for how much acid or base to use for your situation. Frequently pH stays within a desirable range for a considerable time, and then rapidly rises or falls to an extreme. This is usually an indication of the need to do a nutrient change. If you are using hard water, pH has the tendency to climb above 7.5. Sometimes this can be neutralized with acid, though one might consider adding a reverse osmosis unit in an extreme case.

How much pH Up/Down is needed per gallon?
Start out with one milliliter per gallon. Wait 15 To 30 minutes, and test your water again. Frequently you will only need 1 to 2 ml of pH Up/Down per gallon of water. You may need additional pH Up/Down if you have hard water. The General Hydroponics Flora Series is pH buffered to facilitate keeping the pH in a favorable range.

The pH in my system drops below 4 every few days after cleaning and refilling. How do I increase the pH and stabilize it?
The easiest way is to continue adding pH Up. This is generally fine because the additional elements that are added are potassium ions. Potassium is frequently the highest element in hydroponic nutrient solutions. Sometimes pH crashes because of the presence of a large amount of microbial activity in the nutrient solution. This is usually a result of poor maintenance of the system due to infrequent nutrient changes or other stresses. The best way to avoid this scenario is to keep a clean system with adequate nutrition.


Customer Reviews 2 item(s)

Happy ,that's the to go.

Grate.l love it.
They got what you want
In the town I live in grow shops open and close every few months. It's kinda hard to give your plants the help they need when you can't find the right nutes when you need them. I ordered a few things they got here within 2 days felt like I paid a fair price. One of my packages got lost I gave hydrobuilder a call and they had my last package sent the next day. I will keep ordering from here instead of paying stupid prices from ppl that just try to get rich in lil towns

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