I recently got one of the battery operated magnetic stirrers that one of our members, CaOCl2 (Paul), is selling on his website
I have to give the unit two thumbs up minimum!
It works flawlessly and really speeds up water testing, particularly calcium hardness titrations and salt titrations. With the calcium hardness test I got no 'floating endpoint' (purple off color) and the color change from pink to blue was very distinct. The test went very fast. I was able to add the drops of titrant as fast as I could and still count them. The entire test took seconds instead of minutes! Normally, you need to swirl the vial for 20-30 seconds after each drop of titrant to do this test correctly so the reagent mixes and has time to fully react before you add the next drop. For the Taylor salt test it also speeded up the test tremendously and the endpoint was very distinct. It did also speed up TA and FAS-DPD tests but not as dramatically as the prevoius two but it is still an assest to doing these tests. It can also be used to mix the CYA reagent and your sample instead of having to shake the dispenser vial for 30 seconds. This unit is worth every penny as an addition to your water testing equipment. Once you try it you will NOT want to be without it. Pool stores that use the Taylor waterlab for testing use magnetic stirrers because they do speed up the testing and make the endpoint much easier to determine. I have never seen a portable magnetic stirrer anywhere near this excellent price, $65.95 + shipping, and it includes a 25mm x 13 mm stirbar and a pyrex beaker for the testing (most are close to $200 or much more and don't include stirbars or beakers), nor one as compact as this. The unit is well made and the speed control allows you to get exactly the mixing speed you want with very smooth adjustment.
As an added plus I discovered that the vials that come in the TF Testkit (and the Taylor Salt test kit) can be used with the stirrer and the stirbar included (1"x 5/16" or 25mm x 8mm). It's a tight fit and you have to get the vial placed just right but it works wonderfully. I purchased a few stirbars of different sizes on Ebay (and also a magentic stirbar retriever to get the stirbars out of the vial) and discovered that a 1/2"x 1/8" (13 mm x 3 mm) stirbar is PERFECT for the vials in the TF Testkit and the vial in the Taylor Salt test kit. The stir bar was only a few bucks so it was not an expensive addition and well worth the extra investment.
I would have to say that the combination of this magentic stirrer and a TF Testkit is probably the BEST pool water testing setup I have ever used (including the $1000 LaMotte Waterlink Express colorimeter we use at work!) I heartily recommend this product.
So what are you waiting for? Order one! You won't regret it!