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Hach test kits? (Calcium + Magnesium)
- Thread starter IffersTankSlave
- Start date
Everyone - I forgot to add the amount to process paypal payments ($2 for these transactions), and Bec's addition may have increased the shipping (haven't checked yet), so everyone might owe me a few more bucks. I'll figure it all out once I order the kits, and you can pay me at the meeting. Again, it should only be a few bucks each.
Thanks,
Daire
Thanks,
Daire
If you guys are looking for the EDTA it would be easiest if we could get the tetra sodium, tetrahydrate form.
Actually, if you guys can come up with the propylene glycol, I can probably come up with the EDTA. I calculated we would need about 3 liters worth to make the reagent as I calculated above for 30 people.
Ordered. It turns out that Bec's addition did not change the shipping so the total was $351 ($333 + $18 shipping) which works out to be $58.50 per person. So it looks like I owe some of you 60 cents! (except for those making the paypal payments because there was a $2 surcharge). I think we can all call it even. Everyone ok with that?? I'll let you know when I receive the kits.
For those of you that purchased the Hach test kit. I strongly recommend that you dilute your tank water sample prior to testing it or you will find that the end point is hard to see, and you will also end up using A LOT of titrant, especially for the magnesium test. I have found a good dilution to shoot for is 1/7x the original concentration. I use 1 part tank water to 6 parts DI water. I then use this diluted sample for BOTH the calcium and magnesium test. Then I run the tests as the directions suggest.
Rather than adding the titrant of the kit dropwise however, I have found I could get more accurate measurements by adding the titrant using a 1 ml syringe with a needle attached. If you use this method then first test for calcium, then multiply the milliliters of reagent you used by 854 to get ppm of Calcium. If performed carefully you should be able to get resolution of the test down to about 17 ppm. Your tank should be >400 ppm Calcium
For the magnesium test I also use the diluted sample. To get the final magnesium value in ppm use the following formula:
[X ml of reagent * 2144 - (y ppm calcium/0.4)]/4.7 = ppm Mg
where x is the ml of reagent used in the magnesium test, and y is the ppm of calcium determined in the calcium test. Your tank should be >1250 ppm Mg, best about 1350 ppm.
Rather than adding the titrant of the kit dropwise however, I have found I could get more accurate measurements by adding the titrant using a 1 ml syringe with a needle attached. If you use this method then first test for calcium, then multiply the milliliters of reagent you used by 854 to get ppm of Calcium. If performed carefully you should be able to get resolution of the test down to about 17 ppm. Your tank should be >400 ppm Calcium
For the magnesium test I also use the diluted sample. To get the final magnesium value in ppm use the following formula:
[X ml of reagent * 2144 - (y ppm calcium/0.4)]/4.7 = ppm Mg
where x is the ml of reagent used in the magnesium test, and y is the ppm of calcium determined in the calcium test. Your tank should be >1250 ppm Mg, best about 1350 ppm.
