New Vinyl Pool Owner with High CYA and High Water Table

May 17, 2016
45
Mendon MA
Hi All. I love this site as it gave me all the info I needed (or so I thought) to confidently open the pool at my new house this spring. I have never owned a pool but felt confident using the K-2006 test kit. Needless to say everything was going great. I measured and adjusted the Alkylinity, pH, and hardness to be in spec. Then I measured the CYA which came back off the charts. I will be retesting using the dilution method this evening but solely looking at the scale I suspect my CYA is in excess of 200 ppm.

After spending a few hours reading through the TFP forums I have learned I need to drain 75% of my pool and refill to lower the CYA level to achieve the target level. The issue I have is that I live on a lake and have a high water table. I cannot dig more then 3 feet down without hitting the water table. I do not want to drain the pool and risk damaging the liner.

I have also considered renting a water/waste pump and pumping lake water into the pool while draining the pool by way of the waste setting on the pool pump (keep in mind I have well water). This would keep the level fairly constant while cycling out the high CYA water. This method would also allow me to start from the beginning, Any thoughts?

Or Should I just try and dose the pool with Chlorine and see if I can raise the free Cl level to Ben's best guess chart level? Then remove water and replenish at a slow rate (well/rain water)

Any comments will be greatly appreciated.

Thanks

Steve
 
With the cya that high you really do need to replace water. You could drain two feet out which would be about a 50% water replacement and refill and do that a couple times until the cya is reasonable.

Or you could do like you said and remove water and add pond water at the same time.
 
thanks for the input. I have a 16 x 32 pool so 2 feet would be about 25% of the volume and even 2 feet makes me feel uneasy. I will probably go the add and pump out method to help me sleep a little better. Any idea how I would know if the CYA is reasonable after filling the pool with lake water? I am assuming I would need to shock it with bleach first to kill everything prior to testing the CYA? Or can i test the CYA immediately?
 
There is no way the average depth of your pool is 8 feet. So that 2 feet would only be 25%. Most pools have an average of around four feet so 2 foot would be 50% water replacement
 
I understand that. Since I am adding and removing water at the same time I will need to monitor the CYA as I will be removing a mixture of "fresh" lake water and high CYA pool water. Thus I will need a method to the new mixture of water in the pool and it will be murky from the lake portion while containing CYA from the left over pool water
 
Sounds good to me. I will give it a shot this weekend.

Last question. If my water table is roughly 3 feet from the grass line can I drain my pool down 2 1/2 feet? The pool was constructed in 87 and I have no idea if it has steel walls, concrete, etc?
 

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Sounds good to me. I will give it a shot this weekend.

Last question. If my water table is roughly 3 feet from the grass line can I drain my pool down 2 1/2 feet? The pool was constructed in 87 and I have no idea if it has steel walls, concrete, etc?

That is why I suggested a 2' drain ... to stay above the ground water line ;)
You want to be sure to also leave at least 1' of water in the shallow end so the line can not shift.
 
Ok I am currently exchanging water from the lake to my pool. The lake wager has no iron, TA of 20ppm, 30 ppm hardness, and a pH below 7. I used strips and the estimated pH is 6.2. I also have a severe white build up on the bottom of the pool, what I believe is calcium ( solely based on what I have read on the forum). My calcium level was at 270 but the build up was there when I opened the pool. My question is should I adjust the pH and slam the pool or should I target a lower pH to address the calcium? Or should I take a different path?
 
Well really the first step is circulation and a full set of test results.

Getting the pH set in the low 7s and following the SLAM process is the next step.

If it is calcium scaling, there is no easy fix. Either an acid wash or a long period of a LOT of brushing while maintaining a negative CSI.
 
I am currently slamming my pool, thanks for the help. In regards to the calcium, my pool has a vinyl liner so acid washing is a no go. Has anyone had any luck with Leslie's ultimate scale and stain remover, or a similar product? The scaling makes the surface very rough and it is a pain to vacuum...
 
sounds good. My current numbers are as follows:

FC - 12
TA - 80
CH - 30
CYA - 30
pH - 7.6

According to the CSI calculation I am currently at a -.6 with a CA of 30 ppm. Is there any harm to me leaving the water soft and not adding calcium chloride? I am assuming this will help in the dissolving process?
 

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