Drop Based Borate Test Kit.

[rcy100]

I emailed him to see what was happening with Piscines Apollo (since it says he's retired in his posts) and thankfully, he's decided to postpone the retirement. He just needs to update his signature (or tag or whatever it's called).

[rcy100]

I did this test today, and it was not time consuming at all. The colour changes were easy to see and the instructions that came with the kit were concise and easy to follow.

I didn't even think to use my speed stir which I received at the same time. Oh well. Test indicated only 36ppm (I suspected I was low). I'm about to add three boxes of Mule Team and will retest in a couple days. This won't show accuracy, but it will show if the test kit works properly, as after adding three boxes, I should definitely get a higher reading when I test again.

Well, I'm impatient, so I went ahead and tested a couple hours after adding three boxes of Mule Team and 3.5 litres of muriatic acid. Now reading 46, so the borate test kit definitely does what it's supposed to do. My 10 year old daughter helped (the Speedstir was a big hit!!) so that should give you an indication of how easy the test is.

[waterbear]

I did this test today, and it was not time consuming at all. The colour changes were easy to see and the instructions that came with the kit were concise and easy to follow.

I was referring to the Proteam drop based kit where every drop of titrant is equal to 2 ppm boron (as opposed to 4.5 ppm boron for this kit and the Taylor acid and base demand reagents) so the test is about as time consuming as a calcium hardness titiration. When compared with the LaMotte borate strips (which Piscines-Apolo also sells), which take 15 seconds, it is a big time difference for not really that much more precision since the drop test is not being done with a pH meter as I will now explain. The color changes for bromthymol blue are not easy to determine as they go through the intermediate point and it is very important in this test tot only add enough sodium hydroxide to bring the pH to 7.6 (when the blue first appears). You cannot "add one more drop to make sure the color does not change anymore" since that will give you an inaccurate final titration and if you did not go all the way to the blue color but stopped at an intermediate endpoint you will also get inaccurate results. That is why this test is done in the laboratory with a pH meter and not an indicator dye.

[giroup01]

But don’t forget, the Proteam test requires that you determine a color change in 20 mL of water.

The color change is much easier to determine in our test because you are looking down from the top into a more or less narrow cell containing 44 mL of water. And the cell has a white dot at the bottom that increases contrast and facilitates viewing. Because the viewpath is longer this increases the color intensity and makes the color change much easier to spot.

Similarly, in Taylor’s phosphate test, you are required to look down from the top of a (5 mL) long and narrow test cell to determine the sample color. One would be hard pressed to determine the color of that 5 mL sample if it was, say, in a beaker.

44 mL of Taylor Standard Solution R-7062 (pH 7.6 Standard Solution) with BTB produces the same hue as the endpoint obtained (and shown) in our instructions.

[rcy100]

I've done this test a few times now on my pool and all I can say is I find it quite easy (the speed stir makes it even easier) and the colour change (for me anyway) was easily discernable. I've never tried borate strips, so I can't compare, but if the borate strips are anything like the standard strips (i.e. hard to read) I'll gladly keep this drop based test.

However, as everyone is quick to point out, absolute accuracy is not essential with borates, so whatever floats your boat when it comes to testing is good.

[waterbear]

The LaMotte borate strips are very easy to read with distinctive color changes. The Aquachek strips are next to impossible to read. The Proteam kit is very tricky to do right. I am going to try the test with the 44 ml sample and the acid and base demand reagents and see how it goes. (I already have quite a bit of mannitol and bromthymol blue on hand since I have more than one Proteam borate test kit.)
However, like I said before, this particular test is usually done with a pH meter since it is very easy to overshoot the step when you just neutralize the acid used to get rid of bicarbonates in the water (and the sample is usually heated at that point to make sure all the CO2 is gone) so you are only titrating boron and not carbonic acid. Proteam took a novel approach in designing this test kit (and I am sure John Garvin, who holds the orginal patents on borates in pool, had a hand in it).

The trick to see the titrations precision is how repeatable are the results on the same sample. I have not found the borate titration as repeatable as the LaMotte strips.

[chem geek]

I received the Piscines Apollo borates test and tried it out in my pool today. I can see what waterbear is talking about with regard to not having the same sort of "keep adding drops until there is no color change, then do not count the last drop" problem, but I tried the test going past the first transition to blue in several different amounts and basically so long as you end up at the same transition point in the first part of the test (before adding the powder) and the last part of the test, then the results are very consistent. That is, if you stop adding drops when the sample "first turns blue" as indicated in the instructions, then you get the same result as when you go past that by some fixed number of drops to get, say, a deeper blue, so long as you do the same thing in both parts of the test. It does seem to me to be repeatable to within one drop as advertised since I did the test 5 times and got the same result (within one drop) -- again, so long as I stopped at the same point in both parts of the test. The transition to blue is like most other dye tests, not completely definitive in one drop, but it does seem pretty clear within two so should be easy enough to pick one's transition point to be consistent for the second part of the test (i.e. if you go further in the first part to a darker more distinct blue, just be sure to do that later as well).

[waterbear]

Exactly! The problem is that you do not really know the acutal borate reading. You can get repeatable results as long as you stop at the same transition point but where is the PROPER place to stop to get an accurate boron reading? The strips might not have the same precision but the resutls are more accurate in terms of boron levels, IMHO.

[chem geek]

The point I was trying to make was that it doesn't matter exactly which point you stop for the transition so long as you stop in the same place in both parts of the test where that transition is seen. I got the same borate result (same number of drops in the second part of the test) regardless of the transition point I used (just barely blue vs. a more solid blue, for example) so long as I went to the same point in both parts of the test. My five tests even at different transition points all gave me the same borate result within one drop (actually, 4 of the 5 were exactly the same number of drops). Basically, if you go "too far" in the first part of the test, then it is exactly compensated in the second part of the test if you go to the same visible point since what you are trying to measure is the delta that happens after you add the mannitol. The exact transition point from which you start in the first part of the test and end in the second part of the test isn't important (since even a hint of blue is beyond that needed to measure the borates properly).

[waterbear]

so long as I went to the same point in both parts of the test. .

and it is a subjective color that you are trying to achieve by memory. I never said that this test was bad, just that it was difficult to do properly and can be error prone and is time consuming compared to the LaMotte strips..