Alk test kits, Salifert vs Hanna Checker

[MartyF]

I have been using both Hanna and Salifert test kits to measure my dkh. They are off by 3dkh between the 2 for both my tank water and fresh saltwater using reef crystals mixed to 1.025 salinity. The readings from both test kits have been consistent over many tests performed over several weeks. Tank water is reading 10.5 dkh with Salifert and 7.4 on Hanna. Fresh mixed Reef Crystals is reading 12.5 dkh on Salifert and 9.5 with Hanna. This is very frustrating. Which one do I trust? Does it matter as long as ALK remains consistent? I have a 3 year old SPS tank dosing 10ml ALK/CAl to keep consistent levels.

 

[JimWelsh]

It sounds to me like you are overshooting the Salifert endpoint. Please see this: https://www.reef2reef.com/threads/alkalinity-titration-endpoint-ph-salifert-endpoint-color.543556/

 

[madweazl]

I've never seen Reef Crystals below 12 dKh (usually 13) so the Hanna results are surprising.

 

[Bayareareefer18]

There was a recent thread on this exact issue. I found I had a hannah test reading very low. I got a salifert to verify and the two were way off. I've ordered a couple more hannah dkh reagents and the new ones match my salifert

 

[MartyF]

It sounds to me like you are overshooting the Salifert endpoint. Please see this: https://www.reef2reef.com/threads/alkalinity-titration-endpoint-ph-salifert-endpoint-color.543556/

Thank you. Should I just use the Salifert and use the lavender color endpoint and ignore my Hanna? Seems like you Would agree with my thought that stability is more important than the actual number?

 

[MartyF]

There was a recent thread on this exact issue. I found I had a hannah test reading very low. I got a salifert to verify and the two were way off. I've ordered a couple more hannah dkh reagents and the new ones match my salifert

Are you able to provide a link to that thread? I did buy extra reagent for the Hanna, I’ll use those and see what it reads.

 

[richiero]

I have 3 the alkatronic , Hannah and salifert, I think the salifert is more accurate then the Hannah it reads right in line with my alkatronic the Hannah always reads 1 dkh higher for some reason

 

[Bayareareefer18]

Finally found it

https://r.tapatalk.com/shareLink?ur...&share_tid=489630&share_fid=1020&share_type=t

 

[BestMomEver]

Gosh.... I’m interested in this. My Hanna checker has been reading my dkh higher and higher lately. Just the other day, I bought a Salifert kit. I’m gonna use it today. If they’re different, I’ll have the same question? Which is better?

 

[madweazl]

I've had extremely consistent results with the Hanna checker. By chance, are you leaving the bottle of reagent open? I'm wondering if a small amount of evaporation each time it's used is leading to inconsistency. For the past year and half, I've been able to go from bottle to bottle with almost no variation from the end of one to the beginning of the next. I draw in the reagent and cap the bottle immediately, no clue if it's making a difference but it's all I can think of. I also use a syringe to add 10ml of sample water to the cuvette because I dont trust myself to eyeball the meniscus each time I test.

 

[Duffer]

I was getting different readings also, what I found to do with Hanna is keep the cap off the test vile when storing and also I use a syringe to get 10 mil water as I found out the line on the vile is not correct.. once I started doing this my test results have been matching for salfiert and Hanna

 

[richiero]

Interesting I’ll try

 

[richiero]

My caps are always off the test vile when stored I’ll try the 10ml syringe