Hanna Instruments HI758 Marine Calcium Checker Test Kit - Saltwater Aquariums

Hanna Instruments HI758 Marine Calcium Checker Test Kit - Saltwater Aquariums

Calcium presence in water supplies results from passage over deposits of limestone, dolomite, gypsum and gypsiferous shale. Its concentration may extend from 0 to several hundred milligrams per liter, depending on its source and treatment. Calcium is necessary in plant and animal nutrition since it is an essential constituent of bones, shells and plant structures. Calcium in water as carbonate is one of the primary components of water hardness which can cause pipe or tube scaling. The HI 758 Calcium Checker HC is extremely simple to use. First, zero the instrument by adding Reagent A, deionized water and 0.1 mL of sample into the vial. Insert into the HI 758 and press the button. Next, remove the vial and add Reagent B and shake to dissolve. Reinsert into the Checker HC and press the button to read the calcium concentration in ppm on the display. Use for quick and accurate on the spot analysis. Single button operation: zero and measure. Range: 200 to 600 ppm. Resolution: 1 ppm. Accuracy at 25 degree C: +/-6% of reading. Light Source: light emitting diode at 610 nm. Light Detector: Silicon Photocell. Environment: 0 to 50 degree C (32 to 122 degree F); max 95% RH non-condensing.
Top reviews from the United States
More accurate for me then others make it out to be.
To start it’s a Hanna checker so doesn’t get easier. I’m not sure how others like BRS have had such a hard time getting accurate readings with this as every time I use it and double check off a Red Sea kit im within 10ppm ballpark readings which I can verify off dkh and PH readings to see if those seem reasonable and accurate. They do. For example I got a 360 reading one time and checked ph and it was down to 7.83 and dkh was down to 7.4. So right in line with what I would expect those to be based off a 360 reading when I’m normally running 430ish-9.8 and 8.2 respectively.

All that said I still don’t trust it 100% yet and always confirm ph and dk to verify as well as running other testing to make sure it comes within reasonable ranges of what the Hanna says.

One place I think is confusing for many and makes for inaccuracy.. is you fill with 1ml solution then fill to 10ml mark with rodi. I have a feeling many are putting in 10ml rodi on top being 1ml too much and debuting the sample by 10% more then should be. I’m also using the mark on the vial similar to how one is supposed to use the api kits where the top of the bubble is at the line and the bubble protrudes just below. Imop this is how this is supposed to be used. The few times I tried measuring with a syringe I got readings way off what I was expecting and was verified to be wrong with other tests. Maybe the syringes are off maybe people droppers are off? Idk.. but having good eyes and having used and still using api tests for certain things fresh and salt I’m getting readings with 10-15ppm of what it should be be other testing and what dk and ph readings are.