Can anyone confirm this CYA problem ?

[DaveOB]

Is Borax decahydrate (Na2B4O7·10H2O) correct to use ?

Hi all

Just wanting to make sure I have this right before I risk poisoning the pool water in the morning.

After the recent drain and refill, I have the readings ( from a liquid 4-in-1 test kit ) :

FC 3
TA 80
pH 7.3

In addition, the test strip gives the following :
FC 3
TC 3
Alk 100
pH 7.2
TH 100
CYA 35

To raise the TH from 100 to 200, I will add 4kg calcium chloride flakes ( already had these as we use them to de-humidify cupboards ).

Next, pH from 7.3 to 7.5 with 500g Borax.

My concern is the Borax.
I went to the local chemical company and got 'Borax' ( 25kg ~$25 ). The packaging says : Borax decahydrate (Na2B4O7·10H2O) min 99.9% Granular. Is this the correct stuff to use ?

I also want to use the Borax and hydrochloric acid to add borates ( to get to 40 ppm takes 13kg and 6,5 liters acid ), but am a bit stuck as I do not know the borates starting level. I am unable to source borates test strips in our country. Is there an alternate way to test ?

 

[chem geek]

Is Borax decahydrate (Na2B4O7·10H2O) correct to use ?

I went to the local chemical company and got 'Borax' ( 25kg ~$25 ). The packaging says : Borax decahydrate (Na2B4O7·10H2O) min 99.9% Granular. Is this the correct stuff to use ?

I also want to use the Borax and hydrochloric acid to add borates ( to get to 40 ppm takes 13kg and 6,5 liters acid ), but am a bit stuck as I do not know the borates starting level. I am unable to source borates test strips in our country. Is there an alternate way to test ?

Yes, that is the right stuff to use and is identical to the chemical in 20 Mule Team Borax. However, as you note, you need to add acid when you add this borates chemical to increase the borate level. You could instead ask your chemical company of they have boric acid ( B(OH)₃ or H₃BO₃) since you wouldn't need to add acid if you used that instead. It's usually more expensive, however.

There isn't an easy way to test for borates if you don't have a test strip or boron/borates test kit. There is a complicated way if you already have the equivalent of a Taylor K-2006 test kit and had access to mannitol powder and Bromothymol blue indicator dye.

 

[DaveOB]

There isn't an easy way to test for borates if you don't have a test strip or boron/borates test kit. There is a complicated way if you already have the equivalent of a Taylor K-2006 test kit and had access to mannitol powder and Bromothymol blue indicator dye.

Thanks for the reply chem geek.

They did have the Boric Acid available, and the cost was only about 30% higher. I think it would have worked our cheaper than buying the borax and the hydrochloric acid, but I thought the borax was better as I could use that at a later stage if I needed to increase the pH anytime.


DIY Borates Test

I know there are some chemistry gurus on the forum ( looks like you are at the top of those ranks ) , so does this sound correct ?

I think I may have just found a DIY solution to the Borates test.

Just found this video :
http://www.youtube.com/watch?v=i9l-spro3tY

Modifying the information learned here, this is what I have come up with :

The spice turmeric - primary active ingredient is curcumin.
Reacts with Boron to form an intense red complex called rosocyanine, which allows boron to be detected at very low concentrations in water.

The reagent is made by adding a little turmeric to some ethanol. ( not sure why ethanol, but will google for that later )

The exact amount of turmeric used should not be critical, as long as the same reagent solution is used for both parts of the test.

For easy calculations, the Control Solution ( CS ) needs to contain 1000 ppm boron

Using the pool calculator, I find that :
1000 ppm borate
1000 liters water
8818 g borax
4383 ml acid

or

1000 ppm borate
1 liter water
8.818 g borax
4.383 ml acid -- it may be better to make this in a 5 liter batch to make the measuring of the borax and acid a little easier and accurate.

My thinking is that the Control Solution now contains 1000 ppm in 1000 ml water ( or 5000 ppm in 5000 ml ).

This is 1 ppm borate per 1 ml water.

To do the test :

Prepare 100ml pool water in container 'A'
Prepare 100ml of saline water in container 'B'

Step 1
Place a number of ml of reagent ( lets start with 1 ml ) in the pool water container A.
If there is no colour change, add another 1 ml, and add until we get a colour change in the water. Count the ml of reagent added.
If we eventually get no red colour to the water, then we must assume that there are no borates in the pool water.
If we do get a red colour, then borates are present ( reacting with the curcumin ) and we just have to figure out how much borates.

Step 2
Start with 100 ml of plain water in container B ( saline ? ).
Add the same number of ml reagent as was added to the pool water in container A.
Next add 1 ml of the Control Solution ( which we know the exact borates ppm level ) to container B.
Container B now contains 10 ppm ( 1 ppm from 1 ml of CS in 100 ml water = 1ppm / 100ml = 10ppm / 1000ml )
Add 1 ml of Control Solution to container B until the colour matches container A. Count the ml added.

The calculation is simple :
The number of ml ( of control solution ) added to container B -- multiplied by 10 = Borates ppm in pool water.

The containers could be changed to 200ml, making each 1ml of Control Solution added to container B equal to 5ppm, or
The containers could be changed to 500ml, making each 1ml of Control Solution added to container B equal to 2ppm.

Alternatively, after making the 5 liter control solution, mix 100 ml of Control Solution with 400 ml saline ( diluting the control solution 1:4 ) making the control solution now 0.2ppm per 1ml ( and you have 500ml solution to work with ). In this case, every 1ml of CS added to container B = 1ml CS = 0.2ppm in 100ml = 2ppm / 1000ml. So drops of CS added to container B X 2 = ppm in pool water.

If my thinking is correct, do you think it would be best to use the chlorine neutralizer from the liquid test kit to first neutralize the pool water used for step 1 ?

 

[chem geek]

Yes, you would neutralize the chlorine first since it would tend to interfere with the indicator dyes. I don't know how well the procedure you found works, but let us know what you think.

 

[DaveOB]

Partial test results - DIY Borate test.

This afternoon I started with 5 liters tap water, and added 44g borax and 22ml hydrochloric pool acid.

This should create a Control Solution with 1000ppm, or 1 part borate per 1 ml water.

Next decanted from this 200 ml into glass container A.
And then 200 ml plain tap water into glass container B.

Made the reagent with 200 ml saline solution and about a teaspoon of Tumeric spice.

The theory is that I add reagent to solution A until I get a colour somewhere between orange and red.
Then add the same amount of reagent to the plain water in container B.
Next, each 1ml of Control Solution ( 1ml = 1 part ) added to container B equals 5ppm borates ( 1ml in 200ml = 5ml in 1000ml = 5ppm )

The initial test did not create an orange / red colour in container A.

I did also add some dry Tumeric power direct to a small container of control solution ( assumed 1000ppm ) and the colour is still a mid-orange.
From the online tutorial, I was expecting a deep / dark red if the borate level was as high as 1000ppm.

My thoughts are that either :
1. the reagent is too weak.
2. the reagent that I created is incorrect, as I used saline ( I had ) instead of ethanol ( I didn't have ). I am wondering if the ethanol is required to make the active ingredient ( curcumin ) separate out of the tumeric spice.
3. the Control Solution that I created is not at 1000ppm ( the acid is hydrochloric pool acid minimum 30% ).
4. the control solution requires more that 2 hours to convert the borax and acid into borates.
5. something in my calculation is not correct.

 

[DaveOB]

Progress and positive update.

After the initial "no positive results" test ( see previous post ), I did some extra research.

Looks like the curcumin does need to be extracted from the turmeric. So my method of adding the turmeric to water / saline for the reagent was not going to work.

The initial research mentioned ethanol to make the reagent. The ethanol is needed for the extraction of the curcumin.

I also did a bit more reading, and also found that acetone can also be used - and this I have a small bottle of at home.

So I mixed about 70 ml acetone and around 20g or turmeric.

3 different glass containers contained ( if I had my previous calculations correct ) 200ml each of water with :
0 ppm, 20 ppm and 1000 ppm

The 20ppm was made with 196ml water + 4ml of the 1000ppm solution.

After about 3 or 4 minutes ( I am usually more impatient than 3 or 4 minutes ) I added 3ml or the acetone / turmeric reagent solution to a small test batch ( about 50ml ) of the 1000 ppm solution and saw an immediate dark red tinge to the water - Looks like I am on the right track. The same test in plain water resulted in no red colour reaction - just the yellow colour of the reagent.

Next added 20ml of the reagent to the 3 glass containers.

The 0 ppm turned yellow, the same colour as the reagent.
The 20 ppm turned a slightly darker shade of yellow.
The 1000 ppm turned a very, very dark brown.

Now it is still not the dark red that should be present in the 1000ppm container, but it is progress to have the 3 containers all with different colours.

My thinking now is that if I was to let the reagent stand longer ( say, overnight ) and allow the acetone more time to draw the curcumin out of the turmeric, then I will have a more concentrated reagent solution.

I will re-test the 3 containers in the morning and hope to see more colour variance between them, and closer to the dark red in the 1000ppm container.

 

[HouTex]

I'm a big believer in this site and the BBB method. I also believe many pool stores/pool chemical companies mislead customers to sell more high $$ chemicals. That said, trichlor has it's place and it works in some pools.

My father used trichlor pucks exclusively in our pools from the time I was about 8 years old until I was 23. He never had a problem with algae and the water was sparkling. He had sand filters and from backwashing, splash out, and rain, he must have kept CYA in check. I'm pretty sure he never tested for CYA. He only tested for chlorine and pH. Maybe he was lucky.

 

[DaveOB]

Additional Update

Leaving the reagent overnight has not made any difference.

When adding the reagent to the 1000ppm solution, I do notice a very dark red colour ( as I am hoping to see ) at the point where the reagent contacts the water, but it lasts only for a second before dissipating.

So my assumption is that the 3 or 4% curcumin that is in turmeric is not strong enough ( or concentrated enough ) for the reagent to work using smaller volumes of reagent, and by the time I have added a large enough volume of reagent to work, the yellow colouring from the turmeric has overpowered the red colour.

I am next looking at curcumin concentrated capsules at the local health shop as a possible source of stronger curcumin without the colouring from turmeric.

 

[DaveOB]

Update #4 - on track

The likely source of the problem is that I may have my borax and HCl calculations incorrect.

Somewhere I read that the curcumin reacts with borates to form the rosocyanine, but prefer an acidic solution to test in. The rosocyanine degrades in an alkaline solution ( it didn't mention any time frame for this ).

Using some test strips, I checked the tap water I was using for the test solutions. pH measures around 7.
Checked the Control Solution and the colour was very dark red -- so far off the scale above 8.

This means my Control Solution is very alkaline, and that would explain why the drops of reagent added to the 1000ppm container would show the red rosocyanine colour for a brief moment ( less than a second ) and then disappear.

I added a load of HCl to the test container which reduced the pH closer to 7, and the reagent now causes the very dark red reaction in the container that I was looking for.

I also assume that since the control solution is very alkaline, caused by the borax, and the HCl level is low ( proven by the high pH ) then the HCl has not converted all of the borax to borates. Adding more HCl to lower the pH should also increase the borates in the water. If I have the correct amout of borax in the water, then as soon as I get the pH back to the same as the plain tap water, then the acid would have created borates at the 1000ppm level.

I will redo all the tests tomorrow with better measurements and records. If anyone is interested I will post the results / findings here.

 

[chem geek]

After you sort this out then we can review to see if it can be simplified enough as an alternate procedure to use.

 

[Isaac-1]

I'm a big believer in this site and the BBB method. I also believe many pool stores/pool chemical companies mislead customers to sell more high $$ chemicals. That said, trichlor has it's place and it works in some pools.

My father used trichlor pucks exclusively in our pools from the time I was about 8 years old until I was 23. He never had a problem with algae and the water was sparkling. He had sand filters and from backwashing, splash out, and rain, he must have kept CYA in check. I'm pretty sure he never tested for CYA. He only tested for chlorine and pH. Maybe he was lucky.

If that was in the Houston area with an average annual rainfall of nearly 50 inches then there is a good chance the CYA level was kept at least partly in check