Borates Testing Bromothymol Blue (BTB)

[Sunny Blues]

So the old thread about the wonderful Borates test created by JoyfulNoise has become massively long, and a warning popped up that further comments may not be seen so maybe consider starting a new thread. My apologies if I shouldn’t have.

I have enjoyed using Joyful’s Borates test since 2017. It has worked flawlessly for us every year. Today however the test was a bust and I was never able to get the sample blue in the final step with the R-0010. I did it twice too. We added 16 boxes of borax earlier in the day so I know we have borates. I noticed that my mannitol powder and my BTB were both bought in the spring of 2017 so I am assuming shelf life screwed with the success of the test??

I went to Amazon to repurchase fresh mannitol and BTB. I saw Joyful’s post referencing another post recommending a $35 bottle of BTB. Uhhh no, I can’t afford that especially since I need a new speedstir as well. But now I’m confused which other cheaper BTB would be effective since the one I bought in 2017 is no longer available. (And it was only $8 back then)

Can someone please look at this cheaper brand on Amazon and tell me if it would work just as well for the borates test?
https://www.amazon.com/gp/aw/d/B0731Y6GZZ?smid=ACTB8CBED46SR&psc=1

Thanks so much for your help.

EDIT: One more question
We had to shock our pool as we just replaced our liner yesterday and the truck water ate through our 2 gallons of chlorine overnight leaving cloudy water. So when I did the borates test today our chlorine was at 22ppm shock level. Will that interfere with the borates test? Do I need to wait until the chlorine returns back to our normal 7-8ppm before testing the borates?

 

[YippeeSkippy]

Let's ask @JoyfulNoise

 

[mgtfp]

Towards the end of the borates thread I was discussing with Matt the use of Phenol Red instead of BTB.

In the first step where you take pH down to "straw yellow" the goal is actually to bring TA down to zero.

If you test TA first, then you know exactly how many drops of R-0009 you actually have to add for that. If it took you for example 7 drops in the TA test with a 25ml sample (so your TA is 70), then you will need to add 7x40/25=11.2 drops (rounded up to 12) of R-0009 in step 1 of the borate test (when using a 40ml sample, just scale accordingly for other sample sizes)

You can do that blindly, and actually don't need an indicator that covers that low pH-range. I have been using R-0004 Phenol Red for a while now for the borate test, and it works just fine. Just go for orange/reddish instead of pale blue.

 

[Sunny Blues]

Towards the end of the borates thread I was discussing with Matt the use of Phenol Red instead of BTB.

In the first step where you take pH down to "straw yellow" the goal is actually to bring TA down to zero.

If you test TA first, then you know exactly how many drops of R-0009 you actually have to add for that. If it took you for example 7 drops in the TA test with a 25ml sample (so your TA is 70), then you will need to add 7x40/25=11.2 drops (rounded up to 12) of R-0009 in step 1 of the borate test (when using a 40ml sample, just scale accordingly for other sample sizes)

You can do that blindly, and actually don't need an indicator that covers that low pH-range. I have been using R-0004 Phenol Red for a while now for the borate test, and it works just fine. Just go for orange/reddish instead of pale blue.

Thank you.! I’ll keep your instructions aside just in case. But I’ve been using @JoyfulNoise test for 7 years comfortably and flawlessly. I don’t think I want to learn a new way to do the test at this time and screw with my comfort zone. The ol’ if it ain’t broke don’t fix it mentality.

I just want to know if high chlorine levels interfere with Joyful’s test, and if I can use this cheaper BTB offering.

 

[mgtfp]

If chlorine is higher than usual, then just add another drop or two of R-0007 at the beginning to make sure that all chlorine is removed before proceeding with the test.

 

[mgtfp]

I'd say that BTB is BTB. If it's lower concentrated then a few more drops may be required to get the usual colour intensity. Any chlorine interference can be removed with R-0007 as already mentioned.

 

[Sunny Blues]

Ok I ordered the BTB that I linked to above. It worked great. I did need a few extra drops as was noted in the above replies because it’s a bit weaker. The test went off like a charm and so now I know that shelf life of both mannitol and BTB matter. Mine were 6-7 years old so that’s just too old. Lol