Search  for anything...
API

API SALTWATER MASTER TEST KIT 550-Test Saltwater Aquarium Water Test Kit

    • Based on 8,066 reviews
Condition: New
Checking for product changes
$28.00 Why this price?
Save $22.48 was $50.48

Buy Now, Pay Later

As low as $7 / mo
  • – 4-month term
  • – No impact on credit
  • – 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, PayTomorrow, Affirm, Afterpay, Apple Pay, and PayPal. 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 Saturday, Sep 21
Order within 3 hours and 11 minutes
Available payment plans shown during checkout

Style: Saltwater


Features

  • Contains one (1) API SALTWATER MASTER TEST KIT 550-Test Saltwater Aquarium Water Test Kit, including 6 bottles of testing solution, 1 color card and 4 test tubes with cap
  • Helps prevent invisible water problems that can be harmful to fish and cause fish loss
  • Accurately monitors 4 most vital water parameters levels in saltwater aquariums: high range pH, ammonia, nitrite and nitrate
  • Designed for use in saltwater aquariums
  • Use for weekly monitoring and when water or fish problems appear

Description

Protect marine fish and invertebrates from unsafe water conditions with API SALTWATER MASTER TEST KIT. Fish waste, uneaten food, plant refuse and other organic compounds can create harmful levels of ammonia, nitrite and nitrate as well as cause drastic fluctuations in pH. These unhealthy conditions can result in fish stress, gill and tissue damage and even death. The API SALTWATER MASTER TEST KIT accurately measures these four saltwater parameters that are key to keeping your aquarium healthy. It includes six bottles of liquid test reagent, four test tubes with snap-tight caps, a holding tray and a step-by-step instruction booklet with information on how to correct unsafe water conditions. Simply fill a clean test tube with 5 ml of water, add the appropriate test drops and compare results with the color chart. Then follow the recommendations to modify conditions if action is needed. 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 ‏ : ‎ Yes


Product Dimensions ‏ : ‎ 7 x 5.75 x 4.75 inches; 1 Pounds


Item model number ‏ : ‎ 401M


Department ‏ : ‎ Unisex-Adult


Date First Available ‏ : ‎ June 20, 2004


Manufacturer ‏ : ‎ Mars Fishcare


Country of Origin ‏ : ‎ USA


Best Sellers Rank: #1,368 in Pet Supplies (See Top 100 in Pet Supplies) #1 in Aquarium Test Kits


#1 in Aquarium Test Kits:


Item Weight: 1 pounds


Department: Unisex-Adult


Manufacturer: Mars Fishcare


Country of Origin: USA


Item model number: 401M


Date First Available: June 20, 2004


Item Package Dimensions L x W x H: 6.67 x 5.16 x 4.39 inches


Item Dimensions LxWxH: 7 x 5.75 x 4.75 inches


Item Weight: 1 Pounds


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.


Country of Origin: United States


Model Name: SALTWATER MASTER TEST KIT


Color: No Color


Size: 1-Pack


Material: Plastic


Number of Items: 1


Style: Saltwater


Included Components: API Saltwater Master Test Kit


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Saturday, Sep 21

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
  • Apple Pay Later
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

    • Works great
Style: Saltwater
This is a great way to test the salt water in the aquarium to assure your levels are correct. Easy to use.
Reviewed in the United States on June 27, 2024 by Terry Tamraz
    • Product worked great
Style: Pond
Easy to use worked great for checking the lakes pH levels and quality of water.
Reviewed in the United States on July 31, 2024 by Amazon Customer
    • Easy to use
Style: Pond
East to use and helps me keep the pond Ph where it needs to be for the health of the fish and plants.
Reviewed in the United States on June 14, 2024 by Julz60
    • More accurate than test strips, but shouldn't have to but 3 test kits.
Style: Reef
The tests are a bit tedious and time consuming, but worth it for the added accuracy over test strips. The nitrate test requires shaking the bottle for 30 seconds, shaking the vial for 60 and waiting 5 min and some of the other tests require a 5 min wait, so it takes some patience. Some of the color gradients are hard to distinguish, however it's better than test trips for the most part. One cool feature is the test vial caps have ribs inside so that when attached to the opposite end of the vials, it allows for drying of both the caps and tubes when inverted and placed back in the holder. It would be nice if there were a separate test tube holder aside from the box though. One thing I would strongly recommend is dedicating a separate tube to the ammonia and pH tests and do them separately. The reason being is that the ammonia test has bleach in it and any cross contamination will throw off your pH test. It takes a few extra rinses to get the bleach smell out as well. I recommend using deionized water for this if you have it. The negative: I started off with the Freshwater master test kit and immediately liked it over any test strips I've used, which are hard to read. Then later got the saltwater test kit as my hobby progressed. I was dumbfounded to find that that saltwater kit didn't provide me with anything that I didn't already have from the freshwater kit except for a different test card. The chemicals are all the same between the two kits, except for the saltwater kit lacking a low range pH test. The only thing different is a slight variation in the color gradients on the card. This is an unethical marketing practice, hence the one star deduction from an otherwise 5 star review. I now have way more nitrite and ammonia test solution than I will need in a lifetime. As for the reef test kit. It also has overlap with the saltwater kit in that they both have the nitrate test. However the reef kit is lacking the pH, nitrite and ammonia tests. I guess they are assuming you either already have the saltwater kit, or you have no animals in your reef tank and don't need to worry about cycling. Also, the saltwater test kit does not have the calcium and hardness tests that the reef kit has, so you really need both test kits for most marine setups. Maybe you could get away with just the reef kit of you have a nano reef tank with no inverts or fish to produce ammonia, but I would think that corals need a specific pH range, which tells me that the reef kit is likely not meant to be a stand alone kit, but a supplemental kit to the saltwater kit. However they compliment each-other well unlike the freshwater kit, because the only overlap is the nitrate test, which is used the most. If I had to do it over, I would skip the saltwater kit and just acquire the test card, then just purchase the freshwater and reef kit, since those two kits give you all the tests you need for any setup minus the saltwater reference card. ... show more
Reviewed in the United States on May 4, 2020 by Seth
    • Good product
Style: Pond
Ordered this for our Koi pond. Works better than the freshwater kit.
Reviewed in the United States on July 9, 2024 by Bryan
    • A must for keeping fish
Style: Pond
Very easy to use & necessary to keep track of the water quality. So simple to run with the instructions right on the bottles & you get the results instantly. After suddenly losing koi fry, I tested the water only to find acidic levels. A simple solution of baking soda saved the rest. A hard lesson to learn ... show more
Reviewed in the United States on July 20, 2024 by Mari
    • Keep in touch
Style: Pond
Having this test kit is a must have for people that have fish tanks or outdoor Koi ponds. Quick readings and are very accurate. This is a must have item
Reviewed in the United States on August 16, 2024 by Bobby Twiford
    • It Works
Style: Saltwater
I have been using this product every day for the past month in tracking the set up and progress of a new tank. I am a complete newbie to saltwater and this is my first experience with any test kit: Pros: a lot less expensive than lfs, easy to follow instructions, water resistant instructions with result ranges, tons of testing fluid Cons: time consuming (most tests take 5 minutes for results), kit does not come with a pipette to fill test tubes, test tube lids leak when you shake the tubes, results are somewhat questionable as a beginner since most days the test tube color isn’t an exact match for any of the colors on the result card. Overall, it isn’t a bad kit if you just want a kind of baseline for where your tank is at, which is what I need at the moment. A few tweaks by the manufacturer could improve this product by at least one star. ... show more
Reviewed in the United States on November 16, 2019 by Mindy

Can't find a product?

Find it on Amazon first, then paste the link below.