Math is not and never will be my strong suit.

[Yesevil123]

So i need assistance. I tested my KH on February 1st. It took 19 drops to turn to the end color.

Today, feburary 5th, I'm testing my KH again and it took 9 drops this time and it was the overdose color.

The instructions say some math/ number stuff. And it's completely gibberish to me. Can someone help me understand by explaining what it's saying

 

[Gtinnel]

I’ve not used that exact test but to know what your alkalinity level is we would first need to know how much tank water you started with. One version of the test you start with 5ml and the other you start with 10ml of tank water.

 

[Gtinnel]

If you started with 5ml of tank water then your alkalinity is equal to how many drops it took to change to the end color, if the end color was the overdose color then subtract .5 from your alkalinity. So if you started with 5ml and it took 9 drops then your alkalinity is 9dKh, if 9 drops gave you the overdose color then your alkalinity is 8.5 dKh.

Since your two tests gave that much of a different result I’m guessing the first time you used 10ml sample and it took 19 drops, and the other test was a 5ml sample and took 9 drops. If so your first test was 9.5 dKh and your second test was 8.5dKh

 

[Yesevil123]

I’ve not used that exact test but to know what your alkalinity level is we would first need to know how much tank water you started with. One version of the test you start with 5ml and the other you start with 10ml of tank water.

So I have a 55 gallon tank. I did the 5ml start

 

[Yesevil123]

If you started with 5ml of tank water then your alkalinity is equal to how many drops it took to change to the end color, if the end color was the overdose color then subtract .5 from your alkalinity. So if you started with 5ml and it took 9 drops then your alkalinity is 9dKh, if 9 drops gave you the overdose color then your alkalinity is 8.5 dKh.

Since your two tests gave that much of a different result I’m guessing the first time you used 10ml sample and it took 19 drops, and the other test was a 5ml sample and took 9 drops. If so your first test was 9.5 dKh and your second test was 8.5dKh

OOOOHHH okay. So what should the final result be. Meaning what should my dkh be?

 

[fishyjoes]

I have never used this test either but I understand the instructions as follows:

If you started with 5 ml
* end color is green: dKH = number of drops (so 9 drops = 9 dKH)
* end color is yellow: dKH = number of drops minus 0.5 (so 9 drops = 8.5 dKH)

If you started with 10 ml
* end color is green: dKH = number of drops divided by 2 (so 19 drops = 9.5 dKH)
* end color is yellow: dKH = number of drops divided by two minus 0.25 (so 19 drops = 9.25)

I suspect both readings are ~8.5 but the first test maybe you started with 10ml (otherwise the 19 drops doesn't make sense)

 

[Gtinnel]

I have never used this test either but I understand the instructions as follows:

If you started with 5 ml
* end color is green: dKH = number of drops (so 9 drops = 9 dKH)
* end color is yellow: dKH = number of drops minus 0.5 (so 9 drops = 8.5 dKH)

If you started with 10 ml
* end color is green: dKH = number of drops divided by 2 (so 19 drops = 8.5 dKH)
* end color is yellow: dKH = number of drops divided by two minus 0.25 (so 19 drops = 8.25)

I suspect both readings are ~8.5 but the first test maybe you started with 10ml (otherwise the 19 drops doesn't make sense)

I agree with all of this, other than the 19 drops would be 9.5 not 8.5.

 

[fishyjoes]

I agree with all of this, other than the 19 drops would be 9.5 not 8.5.

HA! I guess I'm not so super at math either!

 

[Kooma]

That makes my head hurt. Grab a salifert test kit, it’s Color changing at the value and takes the math completely out of it.

 

[BeanAnimal]

I don't have time this morning. Can one of you just make a nice table, please? Excel, whatever, and screen shot and past her a graphic that she can reference.

Drops - DKH for both 5 ml and 10 ml with a column for readings direct and overdose

 

[Gtinnel]

OOOOHHH okay. So what should the final result be. Meaning what should my dkh be?

There is a pretty wide range of generally acceptable alkalinity ranges for a reef tank, and consistency is the important thing. I always aim for somewhere around 9 in my tanks. If your reading were 8.5 and 9.5 then either of those are fine.

 

[Gtinnel]

I don't have time this morning. Can one of you just make a nice table, please? Excel, whatever, and screen shot and past her a graphic that she can reference.

Drops - DKH for both 5 ml and 10 ml with a column for readings direct and overdose

According to my googling there is one on the back of the instruction card. I know the pro version of the Red Sea alkalinity test (which I do use) has one.

 

[tobster]

I have this test kit and you measure how much titrant was used.
You start with the 1ML in the syringe and once you reach the end color- you subtract how much you used and match that number to the number on the back of the card.
Example- you use .08 ML until you reach the end color. You would look at back of card and see the dkh next to the .08 ML.
You measure by what amount you used, not by what amount is left in the syringe.
Hope that helps. Now my head hurts lol

 

[Yesevil123]

According to my googling there is one on the back of the instruction card. I know the pro version of the Red Sea alkalinity test (which I do use) has one.

I did see that. Honestly all the numbers at the bottom of the instructions threw me off big time. Thanks for your help!! It makes much more sense now

 

[Gtinnel]

I have this test kit and you measure how much titrant was used.
You start with the 1ML in the syringe and once you reach the end color- you subtract how much you used and match that number to the number on the back of the card.
Example- you use .08 ML until you reach the end color. You would look at back of card and see the dkh next to the .08 ML.
You measure by what amount you used, not by what amount is left in the syringe.
Hope that helps. Now my head hurts lol

Are you sure you’re not talking about the pro version of the Red Sea alkalinity test? This version seems to be based on number of drops not volume of solution left or used.

 

[Yesevil123]

That makes my head hurt. Grab a salifert test kit, it’s Color changing at the value and takes the math completely out of it.

I've tried those test kits. I have some still. It just confusion for me

 

[Yesevil123]

Are you sure you’re not talking about the pro version of the Red Sea alkalinity test? This version seems to be based on number of drops not volume of solution left or used.

This is the one I'm currently using. I have the pro for the reef part

 

[tobster]

Are you sure you’re not talking about the pro version of the Red Sea alkalinity test? This version seems to be based on number of drops not volume of solution left or used.

Yep. My bad I missed that. I wasn’t aware they had other test kits.

 

[tautog83]

for $15 more u can press a button twice and just read a number...just saying

 

[Randy Holmes-Farley Verified Community Expert]

Really, the math is not hard. Just plug the number of drops into this equation and out comes dKH: