[DaveSA]

Hi All

New to the forum, and absolutely no chemical experience whatsoever, so hope I am in the right place here.

I live on the east coast of South Africa, and have a home pool, but can not find a local supplier of borates test strips.

So I did some googling for a way to DIY test the borates level in pool water.
I found this video : http://www.youtube.com/watch?v=i9l-spro3tY

Using the info there, I tried to make a small reliable DIY home test, but the results are very opposite to what I am expecting.

I started with the following :

Step 1 - Reagent
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First, I created a reagent solution. This solution is used to react with the borate ions in the water, and changes the color of the water depending on the concentration of borate ions present.
In a small glass jar, added 20 ml and then added the contents of 1 tumeric root extract capsule ( 400mg 97% curcumin )
Mixed and dissolved.

Step 2 - Activator
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I read ( somewhere ) that I needed to add something to make the borates convert to borate ions, and to add Sodium Carbonate or Hydroxide to the water to convert everything to borate ions.
Google says the options here are : Caustic Soda (sodium hydroxide) or Soda Ash (sodium carbonate)
I chose the Caustic Soda ( drain cleaner flakes ) as it was available in a smaller volume container in the hardware store and I only needed 1 spoonful.
To create the Activator, I used 250 ml of water ( I used water from the local Reverse Osmosis ( R.O. ) bottled water shop to ensure minimal contaminates ).
Added 1 medicine measure ( 5 ml ) of the large Caustic Soda flakes.
Stirred and all dissolved within about 10 minutes.

Step 3 - Control Solution
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Next made the Control Solution with :
Large 10 liter plastic water bottle ( left over from the R.O. shop )
Add 5 liters tap water.
Add 44g Borax powder.
Add 22ml hydrochloric acid.
According to my calculations, this should be 1ppm borates. < edit > 1000ppm or 1 part per 1ml. < end edit >

Confusing results
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Next I had 2 glass jars, 250ml water in each.
Jar 'A' I added 10ml of the control solution so it should contain 40ppm borates.

To each jar, I added 3 drops of Activator.

To each jar I added 3 drops of Reagent.

I was expecting jar 'A' with 40ppm to be a darker / redder color than Jar 'B'.

The result was completely opposite. Jar B turned a very dark red, and Jar A was orange.

So I started adding Control solution to Jar 'B' and it did start to get lighter, but after adding 10ml ( same as had been added to Jar 'A' ) it was lighter, but quite far off the colour of Jar 'A'.

So what has happened ?

Is the cucurmin reacting with the Caustic soda instead of the borates ?

Is the roscyanine / caustic soda in jar 'B' somehow 'locked' so it can not change when the same volume of control solution is added to jar 'B' ?

Very confusing, but I need to find a DIY way to test these borate levels ( and I really want to do this DIY so I can say 'I can do science, me' ).

Any advice appreciated.