Which Alk reading to go with

[blcktitanium]

I just tested my Alk with my Hanna Checker and it reads 130ppm (7.268dkh) I thought that was a bit low so I checked it again and it read the same reading of 130. So I used my Red Sea Pro and it came out to 8.4 dkh twice and on the SeaChem it read 7 Dkh with two readings.

So I'm a bit lost but I'm leaning toward the Hanna Checker since it and the seachem results are pretty close.

Which reading should I go with or should I just take the average of the 3 test which would be 7.56dkh?

[Billy1205]

I will just stick to hanna checker

[Bent]

Truthfully, with these hobby kits I think you are seeing a normal sample variance. They aren't lab grade.

If I got those results I would just say your alk is ~7-8 and be done with it. Both numbers are within normal limits.

I think test kits are only good for the "oh crap" factor. Once you start splitting hairs like this, you may as well throw them out the window. JMO.

[MondoBongo]

i'm with Bent on this.

what i find more valuable is tracking the level over time with a single type of test. that way you can start to see the relative variances.

the only time i really worry about double checking my test results is when i get a really strange results, a super-duper low or oddly high reading. then i will cross check to see if maybe my reagent is bad, or perhaps i just screwed up the testing.

but really you're only talking about a variance of ~30ppm. between the tests. i would be much more concerned if you tested again tomorrow and your Hannah check told you 30ppm more or less than what it told you the day before.

[Bent]

Originally Posted by MondoBongo

i'm with Bent on this.

what i find more valuable is tracking the level over time with a single type of test. that way you can start to see the relative variances.

the only time i really worry about double checking my test results is when i get a really strange results, a super-duper low or oddly high reading. then i will cross check to see if maybe my reagent is bad, or perhaps i just screwed up the testing.

but really you're only talking about a variance of ~30ppm. between the tests. i would be much more concerned if you tested again tomorrow and your Hannah check told you 30ppm more or less than what it told you the day before.

Yep, trends are more informative than single point testing.

[toothybugs]

Originally Posted by Bent

Yep, trends are more informative than single point testing.

Perfect example: For the last few months my dKH reading has been 9-9.6, with one reading at 10. A couple weeks ago I added a few SPS sticks to my tank as part of an early move to an SPS-dom mix in my upgrade. Everything has looked good until I noticed yesterday a little loss of flesh at the base of one of my cali torts. I talked about it with a SPS-loving friend of mine (admittedly I was pretty frizzed about it) and I had my first valuable OH DUH lesson with SPS - check my alkalinity.

Last few months: 9, 9, 9.2, 9, 10.2, 9.4, 9.2, 8.9 , 9... last night? 7.4 measured twice. Nuts, that's my animal. Time to start dosing.

[Bent]

Originally Posted by toothybugs

Perfect example: For the last few months my dKH reading has been 9-9.6, with one reading at 10. A couple weeks ago I added a few SPS sticks to my tank as part of an early move to an SPS-dom mix in my upgrade. Everything has looked good until I noticed yesterday a little loss of flesh at the base of one of my cali torts. I talked about it with a SPS-loving friend of mine (admittedly I was pretty frizzed about it) and I had my first valuable OH DUH lesson with SPS - check my alkalinity.

Last few months: 9, 9, 9.2, 9, 10.2, 9.4, 9.2, 8.9 , 9... last night? 7.4 measured twice. Nuts, that's my animal. Time to start dosing.

Perfect example.