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View Full Version : Two months of Pool testing results on a new pool...



Usilpool
07-02-2014, 06:23 PM
I had a 15,000 gallon in-ground gunite/plaster pool built this spring. It has a waterfall from the spa to the pool and a pool fountain. It has a depth of 4 feet and 4.5 feet at the drain. It was finished in April and I had the pool contractor start to do weekly pool chemical maintenance as I learned the ins and outs of managing it by myself. Not long ago I found the Pool Forum and became a member as it looked like this was the place to learn about pool care and maintenance. It was a good choice because after reading many posts I came to understand the chemical needs and became a subscriber to the BBB pool maintenance philosophy.

The 'pool guy' had been using tri-chlor from the start and it seemed like a good way to add chlorine. In reality after checking his records I see that each time he came my chlorine was zero most of the time so obviously, what he was doing was not adequate. Then after reading in the forum about tri-chlor use I decided to give it up. The Cyanuric acid has stabilized slightly below 40 and I don't think that I want to see this rise any further.

I have been doing daily testing to determine what exactly is happening to all chemical values in my pool over time to determine how my pool reacts to a normal operational mode of pump and filter on at 9 am and off at 7 pm. Kreapy Krauly on for 3 hours a day, waterfall on from spa to pool along with a general maintenance plan outlined in the following spreadsheet. Daily chemical results are also listed as well as when I added treatments to the pool.

http://i180.photobucket.com/albums/x298/user_999_999/PoolTreatment_zpsf7cdb380.jpg (http://s180.photobucket.com/user/user_999_999/media/PoolTreatment_zpsf7cdb380.jpg.html)

I have been conservative in my chemical additions as I am slowly sneaking up on what I think is normal for my pool.

pH is easy to control and slowly rises over time. I believe this to be because of the water fall which oxygenates the water.

Free Chlorine falls rapidly. The pool is fully exposed to the Texas sun and probably the water fall contributes to the chlorine loss. I understand I will have to deal with this on a periodic basis and right now I am determining how much to add and at what frequency to add it to the pool. I think I probably will need to add a little more chlorine when I treat the pool to off set the rapid lowering of FC and I will be monitoring this closely for another week or so.

Total Alkalinity is relatively stable but it was low when I took over pool management. I have been adding Sodium Bicarbonate and will continue to do so until the level reaches 80 ppm. I am almost there.

Calcium Hardness is high. The 'pool guy' had no explanation for this as it went up from around 250 to 625 within a one month period. I measured my city water and the calcium hardness is about 100. All I can think of is that the pool is new and perhaps the plaster and grout has contributed to the higher value. I know that the only thing I can do outside of some resin exchange program is to drain some of the water and then fill to dilute the level of calcium in the water. I figure I would need to drain at least half the pool to make a difference and bring it down to the upper level of where it should be. Under the water fall there is small amounts of calcium precipitating on the grout but no where else in the pool is this happening. As the calcium scale does not exist anywhere else in the pool I am thinking that while it is high - maybe I don't need to worry about it right now and as the pool 'ages' I will drain half the pool, maybe this fall, and address an adjustment of the calcium level after the plaster and grout have 'settled in'. Does this sound like a reasonable plan?

Cyanuric acid is a little below 40ppm. I am thinking that I don't want it to go any higher so I have discontinued the use of Tri-chlor which the 'pool guy' had been using. If it goes lower I can always Cyanuric acid add it as needed.

I am going to continue to keep the waterfall active (as I like it and the waterfall sound) and see what the normal chemical values will be under this condition. I understand that I probably would see a different set of chemical values if the water fall were off and have a different set of maintenance parameters to deal with. I may explore this later.

So, if the experts could provide some feed back and let me know if I am on the right track I would deeply appreciate it. I have the K-2006 test kit from Taylor and also have an automatic stirrer (Taylor Speedstir) I use to maintain consistency in testing condition. I have a BS in Zoology so have a full science background and understand the testing parameters. I am retired and the time I spend doing the testing and pool maintenance is really quite small. Firing the 'pool guy' was probably a good thing.

http://i180.photobucket.com/albums/x298/user_999_999/Pool-1_zps3759de3b.jpg (http://s180.photobucket.com/user/user_999_999/media/Pool-1_zps3759de3b.jpg.html)

Watermom
07-02-2014, 08:56 PM
To be honest, I didn't look at your chart as the text was pretty small. But if your CYA is 40 and you are having trouble keeping chlorine in the pool, I think you'd probably do better with a higher CYA. Maybe try 50 and see how that works. If it doesn't, try 60. Some people who live in really hot climates where the pool gets full sun all day find that they have more success with a little higher CYA. One of our former moderators, Janet (aylad), lives in NW Louisiana and deliberately runs her pool with CYA around 80 for that very reason.

Usilpool
07-03-2014, 09:46 AM
The last spreadsheet was too small to read. Let's try this one. I know it is small but I can read this on my screen. Can't seem to get it any larger.

http://i180.photobucket.com/albums/x298/user_999_999/Clipboard02_zpse7b54da7.jpg (http://s180.photobucket.com/user/user_999_999/media/Clipboard02_zpse7b54da7.jpg.html)

Watermom
07-03-2014, 01:56 PM
I still say increase your CYA some. Also, don't test CYA daily. There is no need to do so and it just wastes reagents. As a matter of fact, the only two you need to test daily are pH and chlorine. Testing TA and CH once every couple of weeks is fine unless you use Cal-hypo or if you notice your pH bouncing around. Test the CYA every week or so until you get it where you want it then probably once or twice more per summer is plenty. (Unless you are using trichlor or dichlor. In that case, you'll want to monitor it weekly but not daily.)

You need to make sure that your chlorine level stays within the range in this chart based on your CYA level. If you drop too low, you're risking an algae bloom. http://pool9.net/cl-cya/

If you use the 10mL water sample instead of the 25mL one, then you will make your chlorine testing reagents last longer. You will multiply the drop count by 0.5 instead of 0.2.

Usilpool
07-03-2014, 03:33 PM
Thanks for this information. My intention was only to test daily for a few weeks to determine what my pool is doing then back off to a more reasonable testing schedule as you suggest. Right about CYA testing and I was just testing this during the period of time where I am still making adjustments and I wanted to see what that value did too (it seems to have dropped a bit from May reading and not sure why). I have almost developed a periodic schedule for everything but I am not there yet. Another week should do for me.

I am still interested in my comments on my high Calcium Chloride. Any feedback here?

My chlorine additions need to be adjusted as you indicated. I am working on that.

I am adding Sodium Bicarb today to get the Total Alkalinity up to 90. Will check to see what that does to acid and adjust that tomorrow.