Search  for anything...
API

API FRESHWATER MASTER TEST KIT 800-Test Freshwater Aquarium Water Master Test Kit, White, Single, Multi-colored

  • Based on 28,933 reviews
Condition: New
Checking for the best price...
$35.81 Why this price?

Buy Now, Pay Later

As low as $8 / mo
  • – 4-month term
  • – No impact on credit to apply
  • – Instant approval decision
  • – Secure and straightforward checkout

Ready to go? Add this product to your cart and select a plan during checkout.

Payment plans are offered through our trusted finance partners Klarna, Affirm, Afterpay, Apple Pay, and PayTomorrow. No-credit-needed leasing options through Acima may also be available at checkout.

Learn more about financing & leasing here.

Selected Option

Free shipping on this product

Non-returnable. Transportation of this item is subject to hazardous materials regulation

View our full returns policy here.

Availability: In Stock.
Fulfilled by Amazon
Arrives Sunday, Mar 29
Order within 1 minute
Available payment plans shown during checkout
Protection Plan Protect Your Purchase
Checking for protection plans...

Recently Viewed

Style: Freshwater


Features

  • Contains one (1) API FRESHWATER MASTER TEST KIT 800-Test Freshwater Aquarium Water Master Test Kit, including 7 bottles of testing solutions, 1 color card and 4 tubes with cap
  • Helps monitor water quality and prevent invisible water problems that can be harmful to fish and cause fish loss
  • Accurately monitors 5 most vital water parameters levels in freshwater aquariums: pH, high range pH, ammonia, nitrite, nitrate
  • Designed for use in freshwater aquariums only
  • Use for weekly monitoring and when water or fish problems appear

Description

Most water problems are invisible to the eye. Quickly measure and modify the six aquarium levels that are most important to the health of your freshwater fish with the API FRESHWATER MASTER TEST KIT. To stay healthy and thrive, fish need properly balanced levels of ammonia, pH, high range pH, nitrite and nitrate. These levels can change rapidly and create harmful conditions when fish waste, uneaten food or other organic matter accumulate, or when untreated water is added. If left uncorrected, all of these can be harmful or even fatal to fish, with consequences such as reduction of oxygen, increase in stress and higher risk of disease. The API FRESHWATER MASTER TEST KIT measures these six parameters with scientific accuracy and provides professional results. It comes with four test tubes, a holding tray and computer calibrated, laminated color card. Just fill the test tubes, add the test drops and compare results to the color card. Then follow the recommendations on the card if action is required. With API aquarium products, it’s easy to keep a beautiful saltwater, freshwater or reef aquarium. For almost 60 years API has developed premium solutions with proven and effective results for your family and ours. API offers a range of testing kits, water conditioners, and nutritionally superior food, because we’re dedicated to making a better underwater world. They work to provide a safe, hospitable environment for fish such as tropical community fish, cichlids, goldfish and more. At API, we understand the rewards and relaxation of fishkeeping because we have a passion for fish too.

Is Discontinued By Manufacturer ‏ : ‎ No


Product Dimensions ‏ : ‎ 9.13 x 3.5 x 4.65 inches; 1.15 Pounds


Item model number ‏ : ‎ 34


Department ‏ : ‎ Unisex-Adult


Date First Available ‏ : ‎ June 20, 2004


Manufacturer ‏ : ‎ Mars Fishcare


Best Sellers Rank: #1,423 in Pet Supplies (See Top 100 in Pet Supplies) #2 in Aquarium Test Kits


#2 in Aquarium Test Kits:


Customer Reviews: 4.7 4.7 out of 5 stars (39,663)


Item Weight: 1.15 pounds


Department: Unisex-Adult


Manufacturer: Mars Fishcare


Item model number: 34


Date First Available: June 20, 2004


Item Package Dimensions L x W x H: 6.69 x 5.12 x 4.33 inches


Item Dimensions LxWxH: 9.13 x 3.5 x 4.65 inches


Item Weight: 521.63 Grams


Brand Name: API


Target Audience Keyword: fish


Directions: Follow the instructional booklet directions for individual testing of each water parameter, and test weekly for best results.


Warranty Description: Warranty


Model Name: API FRESHWATER MASTER TEST KIT 800-Test Freshwater Aquarium Water Master Test Kit, White, Single, Multi-colored


Color: Multi-color


Size: Single


Material: Plastic


Number of Items: 1


Style: Freshwater


Included Components: API FRESHWATER MASTER TEST KIT 800-Test Freshwater Aquarium Water Master Test Kit, White, Single, Multi-colored


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Sunday, Mar 29

This item is non-returnable:

Non-returnable. Transportation of this item is subject to hazardous materials regulation

View our full returns policy here.

  • Klarna Financing
  • Affirm Pay in 4
  • Affirm Financing
  • Afterpay Financing
  • PayTomorrow Financing
  • Financing through Apple Pay
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

    • The best freshwater basic testing kit...
Style: Freshwater
You will find this freshwater kit is far more accurate than test strips. The soaking of a tiny doped pad method of test strips just isnt an accurate way to test. This is the industry standard water test kit that most aquarists swear by. 1st, be sure the test chemicals you get are not near expiration. You should easily be able to use this kit for up to a few years before the chemicals included lose their effectiveness. The expiration date is on the kit box and on each bottle of solution. The glass test tubes that used to be included in this kit have been replaced by plastic ones. The glass tubes made cleaning up a breeze and were far better than the plastic ones that don't clean up as well. Also the 5ml fill line is a bit difficult to see on the plastic tubes. It was always inevitable though that you would eventually break a few glass tubes before you got through the 800 tests this kit can provide. They now just assume that by the time the plastic tubes get permanently stained, you'll be on to a new test kit with new tubes. While not a deal breaker, I prefered the glass tubes. Be sure you purchase the kit best suited for the tanks or ponds you keep. This kit is the freshwater version. This kit tests pH in two different ways. If you have ph generally higher than 7.4 you use the high pH test solution. If you have pH below 7.6 youll use the standard pH test kit. This is great of you are keeping multiple tanks with different pH levels or if your one tank tends to bounce around between 7.4 to 7.6. Once you figure out which test best suits your aquariums, youll likely not use the other solution. This kit tests for total ammonia using 2 solutions in one test. Ammonia is a very hazardous chemical to your fish and plants. Use this kit to keep these levels of ammonia at or near 0. This kit tests Nitrites using 1 solution. This is the second step in the nitrogen cycle. While not as harmful as ammonia, it's still something you should strive to get as close to 0 as possible. Now some people using heavily planted and fertilized tanks will actually strive to have this level low but present. This kit tests for nitrates in two solutions for 1 test. While nitrates are not as harmful to fish as Ammonia or Nitrite, most fish keepers still strive for low readings. Long term exposures to high nitrates can still cause harm to fish. Generally youll get rid of nitrates by water changes or heavy plant growth. Many people with heavily planted and fertilized tanks prefer this value to be a little higher to feed the plants but still low to protect the fish. With this test kit testing 4 of your most important chemicals in fresh water, it is a necessity to have on hand. Test strips might be more convenient but are seldom very accurate. This liquid master test kit is the standard if you want true values at an affordable price. It comes in several varieties, depending on whether you have freshwater, marine, reef or ponds. Its a great way to see what is going on in your setup before any loss of life occurs. ... show more
Reviewed in the United States on June 7, 2024 by Don Gray
    • Great price kit that helps maintaining excellent water parameters
Style: Freshwater
Safe to use, good quality and has instructions. Size is great which means the kit lasts forever, it doesn’t smell. Easy to use with clear instructions. Brochure looks great and good material. Price beats all sellers.
Reviewed in the United States on March 2, 2026 by Saif
    • A Must Have Test Kit For Every Level Of Hobbyist
Style: Freshwater
API is a giant among companies that provide aquarium related products.They have maintained their sound reputation by offering innovative products and resisting the temptation to tamper with those which are already established and are time proven, dependable performers.The Fresh Water Master Test Kit belongs in the arsenal of tank maintenance and care products for every level of hobbyist from beginner to advanced. It's important to understand that these kits provide an indication only - it's unrealistic to expect a pin point reading as the tests aren't intended nor made to deliver that. But rather, to enable you to get a decent reading of say, where your PH level is knowing the accuracy may be off a few points sure beats shelling out $200 for a good digital PH meter.It's critical to understand these limitations and that they apply to everyone of the four included tests. PH High Range PH Ammonia Nitrites Nitrates For must of us, Ammonia is the most important because it's the number one killer of aquarium kept fish. The others are important of course, but Ammonia levels should always be checked and checked often. It's also important to pay attention to the expiration dates of the liquid reagents. Expired reagents mean off the charts inaccurate readings. Along with the liquid reagents the kit includes, instructions both in a small manual and attached to each bottle of testing liquid, four test tube, four plastic caps and a color chart. To ensure you get the most accurate reading possible compare the finished result to the card color block in the best possible light and against the most pure white background you can find. Just like computer monitors many of us see color differently which is the inherent draw back of this type of testing. But again, there is nothing else on the market at this kind of price point which can give you enough information to correct and adjust your key water parameters. If you're just starting out in this wonderful hobby, you'll master using this kit in no time and it will help you maintain a healthy and flourishing aquarium. Remember to never, ever rinse even cleaned test tubes in your tank water - even very small traces of testing reagents can be lethal to your fish. Draw water from your tank using a large plastic syringe available at any drug store, super market, or add one to cart from Amazon. For a full range of tests that cover the four most significant parameters you need to stay on top of - you can't beat the API Master test kits, not at this price. You can also buy replacement API test tubes which are sold in boxes of a dozen or 24 at a reasonable price, and a steal at Amazon. ... show more
Reviewed in the United States on April 1, 2012 by Peter Suslock
    • Good kit!
Style: Freshwater
Works perfectly was hesitant on spending more rather than getting test strips but I’m glad I invested in this kit way more accurate and comes with good amount!
Reviewed in the United States on January 28, 2026 by Alyssa
    • Good for the money, tells you where your water quality is.
Style: Saltwater
Work pretty well, not always the most accurate but if you know basically what you're looking for these work great. They don't always measure traces correctly, but traces don't mean much. Fast easy and gives you a good idea of tank water condition.
Reviewed in the United States on January 18, 2026 by Buick48
    • Easy to use
Style: Freshwater
Review Image by Allie Tilley Allie Tilley
Review Image by Allie Tilley Allie Tilley
Great product I thought it was inaccurate but just turns out I wasn’t reading the instructions thoroughly turns out 2 out of 3 of my tanks are healthy! Definitely recommend for beginners like myself
Reviewed in the United States on January 8, 2026 by Allie Tilley Allie Tilley

Can't find a product?

Find it on Amazon first, then paste the link below.
Checking for best price...