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Seachem MultiTest High pH & Alkalinity

Seachem MultiTest High pH & Alkalinity - Main image
$9.31 $13.49 In stock

Category: Aquarium Water Test

Seachem MultiTest High pH & Alkalinity Test Kit

Marine pH should be 8.2—8.4. Tanks dosed with limewater may go as high as 8.6. Natural sea water has a total alkalinity of 2—3 meq/L, but aquarium water should have a total alkalinity of 4—6 meq/L.

This test kit features a unique dye that has a pronounced color change between 8.0 and 8.3, making it the easiest kit on the market to read in that critical range. It is suitable for marine or brackish water only. Alkalinity may be read from the same sample in 0.5 meq/L increments. MultiTest Marine pH & Alkalinity performs over 75 tests and contains a reference sample for validation.

This kit measures total alkalinity. Total alkalinity is a measure of the carbonate, bicarbonate, borate and hydroxide content of the water, expressed as the acid neutralizing capacity of the water in meq/L (milliequivalents/Liter). The expression of alkalinity as meq/L is chemically sound and the most useful way to express this property of the water to resist change in pH.


  • Unique dye that has a pronounced color change between 8.0 and 8.3
  • Multi-cavity plate for simultaneous testing of up to 6 tests at the same time
  • Includes reference for test validation
  • Marine or high pH Freshwater
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Customer Reviews (4.8 / 5 · 4 reviews)

Amelia O. ★★★★★

I was worried my marine tank's pH was creeping too high, but this test kit gave me precise readings down to 8.6, which is perfect for checking limewater dosing. The alkalinity range of 2–3 meq/L matches natural sea water exactly, so I feel confident my corals are stable.

Evelyn ★★★★★

Finally, a test that clearly shows whether my reef tank is holding that 8.4 pH target—the drop-count method makes it easy to read without squinting at a card. My alkalinity readings have been stable at 3 meq/L, which gives me confidence in my dosing routine.

Owen ★★★★★

I’ve been using this kit for a few weeks now and I’m happy with how clear the color chart is for reading pH levels. The alkalinity test is straightforward and gives me results quickly. Took a little getting used to the instructions, but it’s worth it for the accuracy.