Salifert or Hannah

[chadfish]

Salifert dKh reads 9.0
Hanna dKh reads 8.2

Who do I trust?

Or do I just order new reagent for both and try again?

 

[Reefer508]

Test again tomorrow at same time and see which is more consistent or if they both show same drop.

Are they both new, freshly opened?

What are expiration dates?

Personally I use Salifert on 2 tanks regularly and to verify Trident on another.

 

[Slombardi]

I like hannah because you don't have to guess what the number is. Both are with a good range, so I'd pick one and stay consistant with it to see your trend. If the reading seems way off then use another one to double check.

If its 8.2 or 9, don't think it would really matter.

 

[ChrisV]

Honestly I wouldn't assume one is a gold standard. Fresh reagents are of course always a good idea.

As long as they are consistently wrong you're fine. I used to keep my dkh at like 11.5, but decided that if my tests were a dkh point off it would put me closer to the high end than I prefer. Now I shoot for 9. 10 or 8 are acceptable if my Hanna checker is a point out of calibration or something -- as long as it's the same direction each time.

Stable one point off is better then fluctuating a ton but more accurate.

 

[chadfish]

Honestly I wouldn't assume one is a gold standard. Fresh reagents are of course always a good idea.

As long as they are consistently wrong you're fine. I used to keep my dkh at like 11.5, but decided that if my tests were a dkh point off it would put me closer to the high end than I prefer. Now I shoot for 9. 10 or 8 are acceptable if my Hanna checker is a point out of calibration or something -- as long as it's the same direction each time.

Stable one point off is better then fluctuating a ton but more accurate.

I agree, but if they are both so far off, I can’t discount the possibility that one or both readings are drifting over time as the reagent ages. Both are within their expiration,