Calcium Colorimeter HI758 Hanna Checker - Marine Water

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Calcium Colorimeter HI758 Hanna Checker - Marine Water

62% Recommend this to a friend (81 of 130)

SKU: 206202
In Stock: 119
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Quick Overview

Redesigned with new 100 µL Pipette

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


Full Details


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 and is much easier to use. 

Tips for accurate results:

  • Use Hanna HI740230 Demineralized 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 minipipette 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.


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  • use RO water to clean cuvettes!! By phil on 9/21/2017

    Just got an article from Hanna saying to clean the cuvettes with RO/DI water and NOT tap because the tap water has calcium in it!! So I thoroughly cleaned them with RO water and my high (542) reading went away and got my usual 480 reading!!! So use RO water to clean!
  • Consistent and easy to use. By M on 8/14/2017

    I wish I had ignored reviews and purchased this earlier. Works great and easy to use. If you follow the instructions, the readings are consistent. I do not have the problems others have reported with high readings. I use RODI with TDS at 0 (up to 10tds) and have been continuing my testing with the previous trusted test kit. The readings are consistent with the old testkits.
  • Accurate if you have accurate sample By Phil on 8/8/2017

    So, I found out immediately the pipette that Hanna includes in the kit isn't good. I switched to using a syringe and tip from my old Red sea test it and ended up getting accurate tests. I bought the calcium standards along with this meter and run a test using them before I test my tank and found the meter is 25ppm low, so I adjust accordingly. I use RO/ DI water not the distilled as suggested and get good results. So, if you have a good sample amount it's accurate. I like this meter and find it easier than counting drops.
  • Wildly Inaccurate By Joshua on 8/8/2017

    I've used quite a few of the Hanna checkers before, and overall, I've been pretty happy with them. They're good, and any of the complaints you see on here tend to focus on user error or difficulties with the dry packets. This test, however, leaves quite a bit to be desired.

    To use it, you fill a 10 mL vial with 9 mL of D2O and 1 mL of reagent. You shake it, use this to zero the meter, and then add 0.1 mL of your sample plus the reagent. Zero Point One. The first time I used this thing, I got a reading of 580 mg/L Ca. The water had just been tested in lab, and was 460 mg/L. Another test kit showed it to be about that, and certainly no 580 mg/L. A subsequent test with the Hanna meter then showed that the calcium level was 620 mg/L!!!!!!

    A big part of the problem goes to the sample size. You're only using 0.1 mL of sample, and relying on their relatively cheap micropippete to deliver it. There's so little sample in there that, heck, moisture collected on the outside of the pipette could nearly double the sample size (and thus the amount of calcium in the tank). You're also relying on the availability and quality of your D2O. If you don't have an RO system or something to produce at least deionized, you can't use this test kit, and if your system is a little aged... you're introducing a source of error.

    The advantage of the Hanna tests is that they're supposed to be easier, too. You put in your sample and reagent, mix them, get a good number. No counting drops, no comparing charts, no guessing "is it blue NOW?". This test is really quite complicated, and just relies on too small an amount to ever be accurate.
  • Dont BUY By Salvireefer on 8/5/2017

    very inaccurate
  • NOT ACCURATE By Frank on 7/3/2017

    Bought this and was using it for several months. Could never recommend this product. I could not figure out why my calcium levels stayed the same (even high at 490/500) while magnesium and dKh dropped normally. Thought it might be my religious water changes (2x weekly 5%). Finally got suspicious and double checked using a sample of 470ppm calcium. Reading on a Seachem test AND Nyos was 470. Reading on Hanna ..... 550ppm. This is consistent at least. Reading on Seachem for my tank is at 410 and yet on Hanna, 480. Somehow I am getting almost exactly 70ppm too high every time. Don't waste the $50. NYOS does a great job with making color matching easy.
  • This is garbage By Mark on 6/15/2017 it for free, at least I didnt pay for it lol
  • Accurate if you are very methodical By Robert on 5/14/2017

    I get consistent results if I'm very careful. Because of the precision required to get an accurate result I do test again to see if I made an error if I get a reading out of the norm. I think the very small sample is what causes the issues in most cases. Hanna should make this tester less sensitive to user error.
  • Works well By Sparky on 5/3/2017

    I find that the kit works well and is consistent. I noticed a lot of very poor reviews for this product and that it consistently measures high. My first few readings were high but I was not following th directions perfectly. Also, I use distilled water rather than my RODI water and that bings the reading down by about 50ppm. So at this point I am satisfied with the product,
  • Terrible inconsistency By Eric on 4/23/2017

    I have the alkalinity checker and this Ca checker. While the alk checker is great, this thing is junk. Always tests way too low. Save your money and get the Red Sea or Salifert kits. They take more effort to use, but my reef is worth it.
  • Don't waste your money By Deborah on 4/3/2017

    While I love the other Hanna Checkers, the Calcium tester reads false. I have readings that are through the roof and just about pulled my hair out trying to figure out my tank's wacky chemistry until I read online all the other complaints. I then pulled out my Red Sea test kit and checked my Calcium three times and all three were in the normal range.
    Do yourself a favor and skip the Hanna Calcium checker.
  • High Readings By Alex on 3/29/2017

    The sheer number of complaints of high readings is no coincidence and defies the suggestion of user error. I've used this tester a dozen times and every time the readings are 75-100ppm high. Id almost be willing to accept that and simply deduct that amount, but the test readings are never consistent either. For instance, immediately after a water change, I got a reading of 500ppm and a week later before I was going to do my water change I got a reading of 540. I'm not dosing.


Ask a question

Product Questions

Is this the redesigned version with the new 0.1ml pipette?
Question by: Charles Weller on May 17, 2017 8:50:00 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 (Admin) on May 19, 2017 8:44:00 AM
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? pipette shown at 0:50
Question by: Alex on May 18, 2017 3:25:00 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 (Admin) on May 19, 2017 8:59:00 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 11:16:00 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 (Admin) on Apr 26, 2016 1:37:00 PM
does the hanna checker come with the reagents, or do I need to order regents separate?
Question by: jeremy on Nov 26, 2013 8:23:00 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 8:23:00 AM
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 10:50:00 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 10:50:00 AM