3 different alk test brands 3 different results

[killer2001]

I had two bottles of Hanna alkalinity reagent with the same exact batch #. As I was nearing the end of the first bottle, I kept getting low readings... 7.5, 7.6 were the typical values. So I decided to try the new bottle, and I got 8.8 dKH. I tested twice, 8.8 dKH again. I then tested with the old bottle again, 7.5 dKH. I think I'm going to store the bottle in the refrigerator as suggested by @Lasse

 

[Cory]

1.135 grams of sodium bicarbonate (baking soda) in 1 gallon of distilled water or 0 tds ro/di = 10 dkh

Test your test kit

 

[gbroadbridge]

going to buy the salifert and test it against the red sea then just stick with one brand. what do you use to test ca, mag and nitrates/phosphates?

Nitrate I use Hanna HR, but Salifert is close enough and significantly cheaper here.

Phosphate I Use Hanna ULR. Don't waste money on Salifert as it is almost useless under 0.25ppm. Red Sea is accurate, but messy.

Ca and Mg I use Red Sea.
The Hanna Ca (I have one) is very accurate but is also very fussy to use and can give wild results if you are not super accurate. Also expensive reagents.

 

[elysics]

Buy the Alk standard for the Hanna. Confirm its accuracy, and use that.

The problem with the Hanna alk tester is not the sensor, which is what you are testing with Hannas own standards.

It's the reagent that can be off. You can get a generic reference standard from a reputable conpany and do a full test on that and compare what all your tests say to what the bottle is supposed to have. You should do that anyway when getting new tests or completely unexpected results that warrant serious intervention to your tank. Also makes you notice when you are doing a test wrong or something.

 

[dannyboy92]

so, i went and picked up a salifert alk kit. did a water change with red sea blue bucket. retested and the following is what i got.

hanna: 8
red sea: 6.5
Salifert 7.4

 

[stoney7713]

so, i went and picked up a salifert alk kit. did a water change with red sea blue bucket. retested and the following is what i got.

hanna: 8
red sea: 6.5
Salifert 7.4

Pretty close to Hanna, I'd say something is off on the Red Sea. Between Hanna and Salifert that's in range of any deviant and errors they might have. They will never be the exact same.

That's why so many people say pick one and stick with it. Use the Hanna and if you have questionable results use Salifert to cross check.

 

[dannyboy92]

Pretty close to Hanna, I'd say something is off on the Red Sea. Between Hanna and Salifert that's in range of any deviant and errors they might have. They will never be the exact same.

That's why so many people say pick one and stick with it. Use the Hanna and if you have questionable results use Salifert to cross check.

yup exactly what I'm going to do. thanks for everyone's help!