seachem alk test from the MG kit

[StrategicReef]

Well I decided to use the seachem Magnesium kit, there is a total alk test insidem not sure why.. It uses a sringe and tritrate and seems like a better precision.. I got 3.5 MEG/L (.65ML left)

When I use the regular seachem one where you use a needle dropper and add yellow reagent I got about 10 drops which is 5.0 MEG/L before it goes completely yellow.. what gives? Don't they both measure total alkanity..

it's beginning to few like a kid's science kit..

[oct2274]

the kit in the seachem mag kit is complex. you have to run both alk tests in the kit and then subtract one from the other. if you read the instructions it will lead you through the process. It's a bit to complex and I wouldn't use it for my alk readings.

[oct2274]

by the way, the alk reading you are looking for as a measurement in a reef tank is typically the carbonate alk.

[oct2274]

here are the instructions:
Instructions - Total Alkalinity
1. Using the supplied measuring vial, measure out 5 mL of sample and pour into the viewing vial.
2. Add 1 drop of Total Alkalinity Indicator. Mix.
3. Fill the syringe (with white sticker) with Alkalinity Titrant to the 1 cc level. Titrate with the syringe (i.e. dispense titrant solution
to the contents of the collection vial) until color turns from blue to yellow. Gently shake the collection vial after each drop. Read
the volume of titrant used from the cc graduation. Each 0.1 cc of titrant corresponds to 1 meq/L total alkalinity. Each line between
these graduations is equivalent to 0.1 meq/L.

Instructions - Borate Alkalinity
1. Using the supplied measuring vial, measure out 5 mL of sample and pour into the viewing vial.
2. Add 2 drops of Borate Alkalinity Precipitant. Mix gently. Let sit for 5 minutes. Then, add 1 drop of Borate Alkalinity Indicator.
Mix gently.
3. Fill the syringe (with white sticker) with Alkalinity Titrant to the 1 cc level. Titrate with the syringe (i.e. dispense titrant solution
to the contents of the collection vial) until color turns from blue to yellow. Gently shake the collection vial after each drop. Read
the volume of titrant used from the cc graduation. Each 0.1 cc of titrant corresponds to 1 meq/L total alkalinity. Each line between
these graduations is equivalent to 0.1 meq/L.

Instructions - Carbonate Alkalinity
1. Subtract the borate alkalinity result from the total alkalinity result. This is the carbonate alkalinity.
In reading graduations from cc scale, note that scale runs in reverse of dispensing, so that 0.9 = 1 meq/L; 0.8 = 2 meq/L; 0.7 = 3
meq/L; 0.6 = 4 meq/L ppm; 0.5 = 5 meq/L; 0.4 = 6 meq/L; 0.3 = 7 meq/L; 0.2 = 8 meq/L; 0.1 = 9 meq/L; 0.0 = 10 meq/L. Each line
(0.01 mL) in between these graduations equals 0.1 meq/L. If alkalinity exceeds 10 meq/L, it will be necessary to refill syringe and
continue; add the volumes used from both syringe fills to get the total amount of titrant used.

[StrategicReef]

both kits measure TOTAL Alkanity so I would expect somewhat similar results.

[bertoni]

I would expect similar results, too, well, in a perfect world.

[lecher]

Post in the SeaChem forum. They seem to give good customer support. I have the same kit and had a problem with the alk indicator. They promptly mailed out a replacement vail of indicator free of charge.