Finally using proper test kit

[rcortesim]

After being led astray by Leslie’s home tester, I decided to get a Taylor K-2006. So far, I have done 3 tests, and using the Pool Math app, I’ve added recommended chemicals, but I’ve gotten some wildly high results (see attached screenshots). Maybe I should just let it sit for the next few days and things will settle. Of course, I already know that CYA and CH will not budge unless I empty some water. Perhaps my measurements are not exact enough, though I am following the instructions to the letter.

 

[ajw22]

What do you think is a “wildly high result “?

 

[Mdragger88]

For fas dpd testing you can use a 10ml sample & every drop counts as .5 ppm. This will save on reagents and is plenty accurate enough.
It is possible that your pool volume is a little smaller than you think.
You can use the calculator at the bottom of this page

PoolMath

Discover the calculator behind the perfect pool, PoolMath. Dealing with pools has allowed TFP to become the original authors of the best calculator on the net.

www.troublefreepool.com

And this one

Pool Volume Calculator

Check out Pentair's easy-to-use pool volume calculator to calculate the volume of your swimming pool water by choosing the shape, dimensions and depth.

www.pentair.com

To help get a closer estimate.

Extended Test Kit Directions Archives

www.troublefreepool.com

 

[ajw22]

There is no reason to call TA 165. It is 160 or 170.

There is no reason to call CYA 75. We round up to the nearest line. Line CYA should be 89.

Your measurements do not need to be exact. They need to be repeatable by you so you have consistent results.

YOur CH and CYA are high and will require draining the pool to lower it.

Your TA is a function of your fill water.

What is the pH, TA, and CH of your fill water?

 

[rcortesim]

What do you think is a “wildly high result “?

Overall, these numbers are not only way out of target range (per Pool Math), but also the way FC swings makes me question if this is normal.

Looking at the screenshot of tests from Oct 5 to Oct 8…
FC starts at 11, drops to 3.6, then shoots up to 13.5.
Calcium goes from 640 to 1000.
CSI at 0.87, then 1.14.

For the amount of chlorine and acid added after each test, do these results not seem wild to you?

What is the pH, TA, and CH of your fill water?

I'll have to try to test. This raises a question of difference between tap water in the kitchen having a soft water treatment, and the pool fill water that comes from the main supply to the house. Also, the fill water port is below the water level of the pool, and I don't think I have above ground access to it. I guess I can sample water from my sprinklers.

 

[rcortesim]

BTW, so sorry for the extra large image of my tests. I'm still getting used to the forum's functions.

 

[rcortesim]

BTW, so sorry for the extra large image of my tests. I'm still getting used to the forum's functions.

Ok, I figured out how to resize them. Better now.

 

[ajw22]

110 oz of 12.5% liquid chlorine will raise your FC by 5.4 ppm in your 20,000 gallon pool.

If FC dropped from 11 to 3.6 in 2 days with CYA 80 I would suspect you have algae in your pool. But then you add liquid chlorine and get a test of 13.5. Which would say your 3.6 may have been around 8 ppm which would have been a more reasonable drop from 11 to 8.

Are you using a stirring device? They help make testing more consistent.

Drop sizes matter. You need to hold the reagent bottle vertical and let a drop form on the tip and roll off at a rate of about one drop a second. Don't squirt the reagent and don't hold the bottle sideways.

Read Water Testing Errors - Further Reading

 

[rcortesim]

110 oz of 12.5% liquid chlorine will raise your FC by 5.4 ppm in your 20,000 gallon pool.

If FC dropped from 11 to 3.6 in 2 days with CYA 80 I would suspect you have algae in your pool. But then you add liquid chlorine and get a test of 13.5. Which would say your 3.6 may have been around 8 ppm which would have been a more reasonable drop from 11 to 8.

I had algae until I had the filter cleaned a couple of weeks ago. Since then, I've seen no evidence of algae.

Are you using a stirring device? They help make testing more consistent.

Yes, I use the Taylor SpeedStir.

Drop sizes matter. You need to hold the reagent bottle vertical and let a drop form on the tip and roll off at a rate of about one drop a second. Don't squirt the reagent and don't hold the bottle sideways.


Read Water Testing Errors - Further Reading

I think I've been holding the bottles at about a 45* angle and squeezing the drops out. I wouldn't say I squirt it out, but I do apply a bit of pressure.
Thanks for the link. I'll read up on these common errors.

 

[rcortesim]

It is possible that your pool volume is a little smaller than you think.

I've had a number of pool services over the years, and they all estimated the pool to be about 20k. Even when I had the pool resurfaced (changing from plaster to pebble tec, the contractor called it a 20k pool. I've tried, but haven't been able to find a good calculation for my shape.
The Pentair link has a kidney shape calculator, but mine has more curves.
Here's a screenshot from Google Earth. Notice that the widest part is the shallow end and has three steps wrapping around the end that probably should be figured into the depth calculations.

 

[ajw22]

I think I've been holding the bottles at about a 45* angle and squeezing the drops out.

That is the wrong technique. Slower is better for the drops. Don't rush.

Watch these videos...

 

[ajw22]

I've had a number of pool services over the years, and they all estimated the pool to be about 20k. Even when I had the pool resurfaced (changing from plaster to pebble tec, the contractor called it a 20k pool. I've tried, but haven't been able to find a good calculation for my shape.
The Pentair link has a kidney shape calculator, but mine has more curves.
Here's a screenshot from Google Earth. Notice that the widest part is the shallow end and has three steps wrapping around the end that probably should be figured into the depth calculations.

View attachment 613462

The best way to home in on the pool size is by comparing PoolMaths Effects of Adding calculations with actual results tested 30 minutes after adding liquid chlorine or muriatic acid.

Adjust your pool size up for down until calculated versus actual are close.

 

[rcortesim]

That is the wrong technique. Slower is better for the drops. Don't rush.

Watch these videos...

These are good videos, and I had watched them previously. Always good to review.
My flow rate is about the same as what I saw in these videos, and the only difference is that I have been holding the bottles at 45* rather than vertically.

EDIT: I read the article on common errors and come away with this thought. If by holding a bottle at 45* my drop could be 1.5, not just 1, then wouldn't my numbers be even higher? I am adding enough drops to change color, so if I have been dropping the equivalent of 1.5, then the color change occurs after fewer drops.

 

[ajw22]

EDIT: I read the article on common errors and come away with this thought. If by holding a bottle at 45* my drop could be 1.5, not just 1, then wouldn't my numbers be even higher? I am adding enough drops to change color, so if I have been dropping the equivalent of 1.5, then the color change occurs after fewer drops.

If you are squirting the drops off the tip prematurely by squeezing the bottle then your drop sizes are too small and more drops give a higher result.

 

[rcortesim]

If you are squirting the drops off the tip prematurely by squeezing the bottle then your drop sizes are too small and more drops give a higher result.

Squeezing aside, I'm speaking of the angle that I'm holding the bottle. The article I read states:

• Dropper bottles must be held vertically. If held at an angle, the drops of reagent will be the wrong amount. In fact, depending on the angle of the dropper, it could be like using 1.5 drops rather than one.

 

[ajw22]

Hard to say. Just do it correctly.

 

[rcortesim]

The best way to home in on the pool size is by comparing PoolMaths Effects of Adding calculations with actual results tested 30 minutes after adding liquid chlorine or muriatic acid.

Adjust your pool size up for down until calculated versus actual are close.

Ok, so if I just added 32 oz of muriatic acid, I'll test in 30 mins. However, do I compare with yesterday's numbers, or should I have tested immediately before add acid?

 

[ajw22]

Ok, so if I just added 32 oz of muriatic acid, I'll test in 30 mins. However, do I compare with yesterday's numbers, or should I have tested immediately before add acid?

Test before you add chemicals, add the chemical, wait 30 minutes with the pump running, and then test to see the effect the chemical has.

Never add chemicals based on yesterdays numbers.

 

[rcortesim]

What is the pH, TA, and CH of your fill water?

pH: 7.8
TA: 175
CH: 250

 

[rcortesim]

Drop sizes matter. You need to hold the reagent bottle vertical and let a drop form on the tip and roll off at a rate of about one drop a second. Don't squirt the reagent and don't hold the bottle sideways.

This morning, I held the bottle vertically, rather than at 45* angle. Still had to squeeze to produce a drop at the tip, otherwise no drop forms. It's really not that much of a squeeze that I've been doing, only just enough to form a drop and have it release. It looks very much like what I see in the videos. Oh, and yes, I wiped the tip with a moist napkin to remove any static.