Alkalinity Testing What Would You Do?

[fragit]

I use RedSea Pro kit and Hanna DKH, to test my water parameters. My alk testing has some discrepancies between the two. I test minutes in between the two kits RedSea gives me a result of 7.0dkh and Hanna gives me 7.5dkh. Would you go with one or the other or average the two for a dkh of 7.25? I know that RedSea has an accuracy of ±0.025 ppm and Hanna ±0.3 dKH ±5% of reading. What are your thoughts?

 

[ahiggins]

When was the last time the hanna was calibrated? I use those probes for work and theyre extremely accurate after calibration.
Ive also used red sea kits at home before I went with salifert. Im not a fan of them.

 

[Velcro]

I personally just trust the hanna and hold it as steady as possible. Who cares if it's 0.5 dkh off if it's a repeatable result.

 

[cjd]

Testing with kits available to us at home are all inaccurate . My guess is that if you sent that water off to a lab none would be correct. Its all about finding a point of that test kit and keeping it stable . Example, I shoot for 8.5 for alk. Reason being is it really 8.0 or closer to 9 ? Either way I am in a good range and keeping that number from fluctuating is really the goal . Even when I get a new test kit of the same brand I test once with older reagent and test again with the new reagent. As long as the first test shows where my numbers are supposed to be and the new test gives a slightly different number , I know that I shoot for that new number because that becomes the goal range.

 

[fragit]

When was the last time the hanna was calibrated? I use those probes for work and theyre extremely accurate after calibration.
Ive also used red sea kits at home before I went with salifert. Im not a fan of them.

I got the Hanna for Christmas so it's less than a month old. I'm not sure what you mean by probes, it is not a probe it is a colorimeter. I am beginning to question the RedSea accuracy because the color change and the color of the card are so different. It never really matches or has matched the red on the card.

I personally just trust the hanna and hold it as steady as possible. Who cares if it's 0.5 dkh off if it's a repeatable result.

I totally agree, I have been consistently getting readings of 7.5-7.6 with every use since I got it. Stability is key as long as your in range.

Testing with kits available to us at home are all inaccurate . My guess is that if you sent that water off to a lab none would be correct. Its all about finding a point of that test kit and keeping it stable . Example, I shoot for 8.5 for alk. Reason being is it really 8.0 or closer to 9 ? Either way I am in a good range and keeping that number from fluctuating is really the goal . Even when I get a new test kit of the same brand I test once with older reagent and test again with the new reagent. As long as the first test shows where my numbers are supposed to be and the new test gives a slightly different number , I know that I shoot for that new number because that becomes the goal range.

I agree with your thoughts completely. I'm running AquaForest and have a pretty low nutrients. My goal Alk is 7.0-7.5 so as long as I can consistently get a reading on my Hanna of 7.5 then I will consider it a valid test.

Thanks for the help guys.

 

[Elementalj]

My Hanna alk meter came with an almost dead battery. I was getting weird readings compared to my salifert so I ordered the standards kit and a fresh battery.

It's dead on accurate with salifert now.

 

[fragit]

My Hanna alk meter came with an almost dead battery. I was getting weird readings compared to my salifert so I ordered the standards kit and a fresh battery.

It's dead on accurate with salifert now.

What is the standards kit all about? You use it to calibrate the devices correct? How does that work, and does it come with directions? The checker itself didn't have any calibration directions if I remember correctly.

 

[Velcro]

What is the standards kit all about? You use it to calibrate the devices correct? How does that work, and does it come with directions? The checker itself didn't have any calibration directions if I remember correctly.

It's just a check on where your meter reads. There is no way to actually calibrate it.

 

[Elementalj]

It works though. You can find out if your battery isn't producing enough charge to energize the background light to make accurate measurements.

They're just standards but are very useful. You can find them at BRS.

 

[Elementalj]

Ps. Don't open the cuvettes that come in the standard pack. Exposure to the atmosphere can foul them.

 

[Elementalj]

On another note the titration fluid that comes in the Hannah meter kit can sometimes develop this funky mold or fungus in the bottom of the bottle and when you pull the solution into the syringe you end up pulling in some of these little chunks. Make sure that the titration solution is completely clear before you put it into the cuvette. I'd also check the expiration date on the testing fluid.

 

[fragit]

Thanks guys! I will do all of those things. Gonna need to place a BRS order soon anyway, so I will get some more reagent, the stands kit, and go from there. Thanks again!

 

[ahiggins]

I got the Hanna for Christmas so it's less than a month old. I'm not sure what you mean by probes, it is not a probe it is a colorimeter. I am beginning to question the RedSea accuracy because the color change and the color of the card are so different. It never really matches or has matched the red on the card.

OH! I use their probes lol I didnt know they made colorimeters too I use HACH for colorimeters, way more accurate but I dont know if they have alk ones.
Still, redsea is meh at best when Ive used them. Good luck

 

[FranklinDattein]

In addition to the previous advice, you can test alk of natural saltwater (or any other water with well known alk, like a fresh mix of synthetic salt) and check the accuracy of your test kits.

That is how I calibrate my eyes to the not so obvious color change in Red Sea alk test kit.

 

[Ewilson]

My salifert and Hanna dkh meter are 1.1 dkh off

 

[fragit]

Got my calibration fluids for the Hanna dkh meter today. It says must be within 90-110 ppm I get a reading of 5.7dkh anybody know the conversation?

 

[MaddyP]

Got my calibration fluids for the Hanna dkh meter today. It says must be within 90-110 ppm I get a reading of 5.7dkh anybody know the conversation?

1ppm = 0.056 dkh. That would mean 5.7 dkh = 101.7 ppm alkalinity, proving your Hanna checker falls almost exactly nominal of the +/- 10 ppm tolerance allowed. In other words, as long as the standard are accurate, your Hanna checker is accurate.

 

[adhd_nerd]

dkh/.056

 

[fragit]

Thanks folks!