Alkalinity test?

[moseley75]

I have a RedSea marine care test kit and a RedSea reef foundation test kit. Today I used both to check my alkalinity. Huge difference in the readings. The reef foundation alk test returned a Alk of 5.9 and the marine care test returned a reading of 8.5. I tested with both multiple times to ensure I wasn't doing something wrong and got the same result every time.
They both have an expiration date of 11/18. Which one should I rely on?

 

[Tori]

I don't think things in your tank would look to good if ALK is staying at 5.9. Maybe try a third kit? Good excuse to grab a Hanna Checker.

 

[Fishfinder]

Are they both titration kits?

 

[moseley75]

5.9 is way to low.
The marine care kit is not a titration kit with a syringe. It utilizes a small dropper. The reef foundation is.

 

[luke33]

I would try a different test. The hanna checker is the best test kit and tritration wise I'd get a nyos alk kit from premium aquatics. It's my favourite titration alk kit and very accurate.

 

[Randy Holmes-Farley Verified Community Expert]

There's no way we can tell which, if either, is accurate.

 

[moseley75]

Looks like I'm going to have to get a Hannah checker. Wanted one anyway.

Thanks all for the quick responses.

 

[Bigtickets]

+1 on the Hannah checkers. They are what I use.

 

[Randy Holmes-Farley Verified Community Expert]

Of course, if that Hanna disagrees, there's still no way to know which, if any, are accurate, without testing a standard, or a DIY alk test with a standard acid.

 

[moseley75]

Ok @Randy Holmes-Farley. So I read your article on DIY testing. I can get a pH tester as easily as a Hannah alkalinity checker. What one would you recommend?

It appears that Hannah makes one that can be calibrated using one or two of the three points 4,7or10.

 

[Randy Holmes-Farley Verified Community Expert]

Calibration at 7 and 10 is best for reef use. Unless you need below pH 7 for a CaCO3/CO2 reactor, that is a fine way to go.

 

[Randy Holmes-Farley Verified Community Expert]

I don't really know the exact method Hanna uses for alk, so I'm a bit reluctant to comment on it and where it might fall short.

 

[moseley75]

I have been looking at the Milwaukee web site. They have several some of which are at BRS. The one I like bets though is the mi 180 which has several other test including salinity and orp. Do you have any knowledge of this meter?

 

[Randy Holmes-Farley Verified Community Expert]

I don't, but Milwaukee generally makes good products.

 

[moseley75]

Thank you Randy for all the advice.
I contacted Red Sea and discovered that the test that comes with the Alkalinity Pro test kit is +/- .14DKH while the marine care is +/- 1dkh.
I am going to get a pH tester from Milwaukee and some acid and verify my results but for now I'll use the Alkalinity Pro results.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you Randy for all the advice.
I contacted Red Sea and discovered that the test that comes with the Alkalinity Pro test kit is +/- .14DKH while the marine care is +/- 1dkh.
I am going to get a pH tester from Milwaukee and some acid and verify my results but for now I'll use the Alkalinity Pro results.

Sounds good.

Happy Reefing.