Hanna Instruments

Calcium Colorimeter HI758 Hanna Checker - Marine Water

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Redesigned with new 100 µL Pipette

Accurately check your reef tanks calcium level with the Hanna HI758 Calcium Checker.

Three simple steps to results. The Hanna Calcium Checker bridges the gap between simple chemical test kits and professional instrumentation. Accurate, affordable and easy to use. First, zero the instrument with your water sample. Next, add the reagent. Last, place the vial into the Hanna Calcium Checker, press the button and read the results. Done.


Easier to use and more accurate than chemical test kits.

Tips for accurate results:

  • Use Hanna HI70436 Deionized Water
  • Make sure testing vials are clean of any debris
  • Vials must be dry on the outside with no fingerprints
  • Violent shaking will cause microbubbles that can affect the reading
  • Do not let the sample sit too long before taking a reading


New MiniPipette - The new mini pipette has a 2-stage plunger that will let you accurately dispense your 0.1mL tank water sample. The pipette is spring loaded and will allow you to retrieve and dispense 100 µL. Just attach the pipette tip, and press the button down until it stops the first time. Then place the tip into your tank water sample and slowly let the plunger spring back up. Move the pipette to your testing vial, and press the plunger down to the first stop to dispense the liquid it took in. 


Dedicated to a single parameter - Designed to work with HANNA's liquid reagents. Uses 10 mL glass cuvettes.


  • Range: 200 to 600 ppm
  • Resolution: 1 ppm (mg/L)
  • Precision: ±6% of reading
  • Light Source: LED @ 610 nm
  • Light Detector: Silicon photocell
  • Environment: 0 to 50°C (32 to 122°F); RH max 95% non-condensing
  • Battery Type: (1) 1.5V AAA
  • Auto-off: After 10 minutes of non-use and after read
  • Dimensions: 81.5 x 61 x 37.5 mm (3.2 x 2.4 x 1.5")
  • Weight: 64 g (2.25 oz.)
  • Method: Adaptation of the zincon method

Weighing a mere 65 g (2.3 oz.), the Checker®HC easily fits into the palm of your hand or pocket. Use for quick and accurate on the spot analysis. Single button operation: Zero and Measure Operated by a single AAA battery.


Replacement Reagents - HI758-26 Calcium Checker Reagents


Instructions Instructions

More Information
UPC 757901787669
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Product Questions

Is this a hole kit that comes with the case too
Question by: Roberto on Jan 23, 2018, 10:15 AM
Yes, the Hanna Checkers do include a plastic storage case.
Answer by: Charlie on Jan 25, 2018, 6:55 PM
From Hanna's official video (link attached) of this checker in 2016, it comes with a 0.1 ml pipette for adding the sample water. Does the checker sold at BRS comes with the pipette or green syringe?
https://www.youtube.com/watch?v=OG1cliQjDZk pipette shown at 0:50
Question by: Alex on May 18, 2017, 3:25 AM
These are indeed the new test kits with the .1 mL pipette included! We're working on getting an up-to-date photo on the website to reflect this.

Have a great weekend!
Answer by: Zack on May 19, 2017, 8:59 AM
Is this the redesigned version with the new 0.1ml pipette?
Question by: Charles Weller on May 17, 2017, 8:50 PM
These are indeed the new test kits with the .1 mL pipette included! We're working on getting an up-to-date photo on the website to reflect this.

Have a great weekend!
Answer by: Zack on May 19, 2017, 8:44 AM
Are the reagent packets really that hard to open and get into the vials?

It seems that the biggest/only gripe about this unit in the reviews is that it uses a powder reagent and not a liquid.

Is it really that hard to open the packet and get all of the powder in the vial?
Question by: G on Apr 20, 2016, 11:16 AM
Great question!
We do not have issue with the packets, As long as the packet is shaken to the the power into one corner, The flap is then cut and the packet folded to allow the power to fall down the crease in the packet we have not had issues ourselves.
Answer by: Connor on Apr 26, 2016, 1:37 PM
I would like to buy a Hanna checker for nitrate please but can not see one on
Your web site
Question by: Stuart ray on Apr 10, 2014, 10:50 AM
Hi Stuart,
They do not make a Nitrate checker. If/when they do though we will bring it in.
Answer by: Bulk Reef Supply on Apr 10, 2014, 10:50 AM
does the hanna checker come with the reagents, or do I need to order regents separate?
Question by: jeremy on Nov 26, 2013, 8:23 AM
Hi Jeremy,
The Hanna Calcium Checker comes with enough reagent to do about 25 tests.
Answer by: Bulk Reef Supply on Nov 26, 2013, 8:23 AM