API pH Freshwater Aquarium Test & Adjuster Kit, 250 count

$5.84 First Time Autoship Price
this order
Save 35% (up to $20) today when you set up Autoship. 

$8.53 Autoship Price
(-5%) future orders
  • Keep saving 5% on every order
  • Get deliveries on your schedule
  • Skip, change, or cancel anytime
$8.98 Chewy Price
($0.04 /ea)
Save $9.30 (-51%)
$18.28 List Price
Promo, Spend $100, Get $30 eGift Card with code NEWYEAR
Promo, New Customers Only: Spend $49+, Get $20 eGift Card + Free Shipping with code: WELCOME

In Stock
FREE 1-3 day delivery on first-time orders over $35
Free 365-day returns

No interest if paid in full in 6 months on PayPal purchases of $149+. .

About This Item

Details

  • Complete kit monitors and adjusts aquarium pH and creates healthy freshwater conditions.
  • The kit tests the pH of freshwater within a 6.0 to 7.6 range and adjusts the levels as needed.
  • Includes three 1.25 ounce bottles of pH Up, pH Down and pH Indicator solutions and pH results color card.
  • Follow the recommendations and use either the pH Up or pH Down solution to adjust levels.
  • Provides 250 tests per box.

Instructions

FAQ

Learn More About API From Our Team of Experts

About API Testing

Testing the Waters

For fish to thrive, their aquarium water must be similar to the water in their natural environment. Poor water quality can cause stress, illness and even the loss of your fish. Important water quality parameters include ammonia, nitrite, nitrate, and pH. These can vary over time, and they are invisible to the eye, which is why it is necessary to test weekly. Choose from a wide range of API testing options like the Freshwater Master Test Kit or 5-in-1 Test Strips to accurately evaluate your water.

Pressed for Time? Just Dip and Read

Simply dip an API test strip into your aquarium, swirl it twice, and then use the color-coded chart to determine if your water is within safe parameters or if adjustments are needed. That’s it! API test strips are available in a 5-in-1 version, which includes testing for pH, nitrite, nitrate, carbonate, and general hardness. Ammonia and pH test strips are also available so you can mix and match according to your needs.

The Scientific Approach

Get professional results from the comfort of your home with API test kits. Measure up to six parameters with API Master Test Kits, or pick and choose from a wide variety of individual test kits. Both types of kits come with test tubes and a laminated, calibrated color card. API test kits allow for numerous tests, making them an inexpensive way to help keep your aquarium water quality in check.

How to Correct Aquarium Water Parameters

Too Much Ammonia?

Ammonia is released into the water through gills, urine, uneaten food and more. API Ammo-Lock detoxifies it instantly.

Inappropriate pH Levels?

Fish require a specific pH level to thrive. Use API pH Down to lower freshwater aquarium water pH to the right level.

Too Much Nitrite?

Use API Quick Start to quickly consume nitrite and help maintain an active biological filter.

Nitrates Too High?

API Nitra-Zorb helps remove nitrate and other toxins that can be harmful to fish and lead to algae growth.

About API

The team at API has a passion for fish and understands the rewards and relaxation fishkeeping can bring. For almost 60 years, they have developed premium products with a focus on proven and effective results. API offers a range of testing kits, water conditioners and nutritionally superior fish foods. They are dedicated to making a better underwater world for the benefit of fish and those who keep them.

Shop API

Questions & Answers

3 Customer Questions


Is API ph up and API ph down safe for use with betta fish?

Answer by Chewy • Jun 12, 2021
This product is safe for betta fish.

Are the ph up and down solutions safe for tanks with live plants?

Answer by Chewy • Sep 09, 2025
The API PH UP and API PH DOWN products are able to be used in aquariums containing live plants or any other organisms that would benefit from the pH changing to a more optimal level for them. Just keep in mind that different organisms have different best target pH levels and so do make sure that the species are best matched in the aquarium to all enjoy similar water pH and other conditions / water parameters.

How many tests can be done from one kit?

Answer by Chewy • Sep 08, 2020
This kit provides 250 tests per box.
4.5
Rated 4.5 out of 5 stars
33 Ratings

13 Customer Reviews



Rated 4 out of 5 stars
By Lee on Dec 7, 2025

It works

I have no problems with it it works the way it's supposed to

I have no problems with it it works the way it's supposed to


Rated 5 out of 5 stars
By Quentin on Jun 6, 2025

Assortment of Aquarium products.

You have more items for an aquarium that a local Aquarium store.

You have more items for an aquarium that a local Aquarium store.


Rated 4 out of 5 stars
By LUCINDA on Dec 2, 2024

It is a fair test of water PH

The product needs more informational text. I was making the water more acidic than alkaline until I experimented and realized PH needed to be up not down.

The product needs more informational text. I was making the water more acidic than alkaline until I experimented and realized PH needed to be up not down.


Rated 5 out of 5 stars
By Suzanne on Nov 25, 2024

One Kit

This aquarium water test kit is easy to use. It comes with Ph up or down drops. No need to buy 3 products.

This aquarium water test kit is easy to use. It comes with Ph up or down drops. No need to buy 3 products.


Rated 5 out of 5 stars
By Ramon on Jan 19, 2024

Customer Service

Products I bought from Chewy are good, but can be bought else where. But their customer service so far has proven to be excellent and very rare to find else where. Bought

Products I bought from Chewy are good, but can be bought else where. But their customer service so far has proven to be excellent and very rare to find else where. Bought a bottle that came with a broken top. Immediately they sent me another. Bought the wrong bulb and they sent me another without any hassle or returns. FedEX lost a shipment that they claim to have been delivered but without proof. Chewy again sent me another order without any hassle. FedEx is a good example of a company which at one time had good customer service but now is the worst and not reliable. Last time FedEx lost an air conditioner they claim to have been delivered. I live in a mail service building that don't loose packages. Wish they did not use FedEx. ***** Great customer service.


Rated 2 out of 5 stars
By MamadeMax on Apr 9, 2022

Didn't work

I followed the instructions carefully and put 20 drops in my 10gal tank but the test kept looking exactly the same, I had to add more product to raise the PH, but

I followed the instructions carefully and put 20 drops in my 10gal tank but the test kept looking exactly the same, I had to add more product to raise the PH, but still doesn't work.


Rated 5 out of 5 stars
By SANDRA on Dec 21, 2021

Great Product

Works like it's supposed Ph goes up like it says. Highly recommend it. Would buy again.

Works like it's supposed Ph goes up like it says. Highly recommend it. Would buy again.


Rated 5 out of 5 stars
By Luna on Sep 14, 2021

Easy to use, easy to adjust, wonderful !

This product is perfect for a beginner like me ! I need a higher PH for my snails, and this test is SUPER easy to do as well as to adjust ! All you need to do is

This product is perfect for a beginner like me ! I need a higher PH for my snails, and this test is SUPER easy to do as well as to adjust ! All you need to do is put tank water in the tube and test ! The adjustment liquid is super easy to have on hand as well in case I ever need it ! Eases all my worries !!


Rated 2 out of 5 stars
By Jake on Aug 26, 2021

Out of pH lower and just got kit

Took the hole bottle just to lower pH in 30 gallon tank that was cleaned not long ago

Took the hole bottle just to lower pH in 30 gallon tank that was cleaned not long ago


Rated 5 out of 5 stars
By Myles on Apr 8, 2021

Quick & Easy

I was impressed with how simple and quick it was to test the water. The card was easy to compare and match. I honestly couldn't have asked for a better test kit

I was impressed with how simple and quick it was to test the water. The card was easy to compare and match. I honestly couldn't have asked for a better test kit to use, as a beginner. As an added bonus, I tested my tap/well water and was surprised at the results. Everything tested neutral! I'm pretty tempted to start testing different water sources and possibly include this kit in a science project for my child's homeschooling. I would definitely recommend this product to anybody looking to test some water.