Weird crystals in pool - what to do?

[mknauss]

What does the TA test show?

 

[JoyfulNoise]

Don’t follow PoolMath yet. That pH number is wrong.

 

[JamesW]

I think that you are getting mixed up on the pH and TA tests.

The scale might be calcium sulfate.

Do you use dry acid or other sulfate compounds in the pool?

 

[jennz4b]

What does the TA test show?

A sample diluted with 50% distilled water turns from green to orange after three drops (I have confused myself Now whether the result of this is 30 or 60.

 

[mknauss]

If you used a 25 ml sample, that would be 15.

Why would your TA be so low with a new pool?

 

[jennz4b]

What does the TA test show?

30

 

[jennz4b]

If you used a 25 ml sample, that would be 15.

Why would your TA be so low with a new pool?

Confession- Probably because when thought that I couldn’t test for Ph or TA with a free clorine of 22, I periodically added some Muriatic acid (I know- seems really dumb now!!!)

 

[mknauss]

OK. Let's see what @JoyfulNoise has to say. But I suspect you need to add some baking soda.

 

[jennz4b]

Confession- Probably because when thought that I couldn’t test for Ph or TA with a free clorine of 22, I periodically added some Muriatic acid (I know- seems really dumb now!!!)

I did this because prior to the SLAM, my pool had tended to have the ph rise easily, because it was a new pool. I told myself I was keeping to the same acid adding schedule I used when I regularly tested ph….

 

[jennz4b]

OK. Let's see what @JoyfulNoise has to say. But I suspect you need to add some baking soda.

I have some baking soda and borax but will re do my tests and wait to see what @joyful noise says before adding stuff! Thanks again for your advice!

 

[JoyfulNoise]

Ok. You misunderstood me or I was not clear enough …

You only use the dilution method to measure pH when the FC is above 20ppm. You DO NOT use a diluted sample for TA.

For the TA test, with an FC above 20ppm, I would recommend the normal water sample (25mL of straight pool water) and add 2 drops of R-0007 at the beginning, not 1 drop.

Retest TA and post that result. Forget about pH for now.

 

[jennz4b]

Ok. You misunderstood me or I was not clear enough …

You only use the dilution method to measure pH when the FC is above 20ppm. You DO NOT use a diluted sample for TA.

For the TA test, with an FC above 20ppm, I would recommend the normal water sample (25mL of straight pool water) and add 2 drops of R-0007 at the beginning, not 1 drop.

Retest TA and post that result. Forget about pH for now.

TA = 30 (undiluted sample) I only diluted the ph sample! Confused myself. Thanks for your patience!

 

[JoyfulNoise]

You’re TA is very low. I suggest you raise it to at least 50ppm using baking soda.

Assuming that no one was using dry acid (sulfates) in your pool, here’s my theory based on what our plaster experts have posted in the past - the plaster has been kept in a constant state of low saturation (negative CSI). This has impeded or retarded the formation calcite (CaCO3) in the plaster matrix. Calcite formation is as critical to cement materials as the hydration of calcium silicate. The raw plaster contains a large amount of portlandite (CaOH2, aka, lime). The calcium hydroxide is also extremely alkaline and will drive pH up right near the surface of the plaster. This causes calcite to form near the surface and what your seeing the robot pickup is that calcite (probably mixed with other stuff as well).

The trick with new plaster is this - you need to keep the water saturation balanced as much as possible - not negative, not positive, but near zero as much as you can. The easiest way to achieve that is to keep the TA at recommended levels (usually 50-80ppm) and the let the pH stay in the range between 7.6-7.9. That way the calcium hydroxide in the plaster can fully carbonate and form a properly hardened calcite surface layer. Since you have an SWG you’ll need to keep an eye on it, or not use it much, because the balanced saturation water will likely cause scaling inside the cell. Once the plaster settles down, then you can use the SWG more.

 

[JamesW]

I put a drop of Muriatic acid on the crystals and didn’t see bubbling. Same thing when I let this dry to a white flakey powder.

Maybe see if the University of Arizona Chemistry lab will analyze the sample for you and bring a water sample to let them test for sulfate.

In the case below they submitted samples to the University of Arizona Chemistry lab for infrared spectroscopy.

The IR scan confirmed they were indeed calcium sulfate.

The Mystery of the Pointed Crystals

Seemingly overnight, this pool was covered in sharp crystals. Where did they come from?

www.aquamagazine.com

Contact Us | UArizona Department of Chemistry and Biochemistry

cbc.arizona.edu

Note: You can also try ASU; I hear that they are pretty smart there as well.

 

[JoyfulNoise]

Note: You can also try ASU; I hear that they are pretty smart there as well.

… oh wait, you were being serious …

If you need advice on how to work on your tan or what type of basket weaving works best in the desert, then yes, ASU is your go-to source ….

 

[JamesW]

They need to test for sulfates for their beer brewing class.

New ASU course covers everything from hops to hiring in the business of beer

Students in Agribusiness 494 learned about price elasticity and regression analysis this semester. And they also heard about hop farms and spontaneous fermentation. “The Business of Beer” is a new course that could lead to teaching business principles vertically, according to Tim Richards, a...

news.asu.edu

Also, the next time you need a handmade picnic basket, you should appreciate the hard work of ASU graduates.

 

[jennz4b]

Thank you all! I will work in getting my ph and TA balanced and turn off the salt cell for now!

 

[JamesW]

Maybe check the cell for any sort of scale.