High Chemical Hardness

[wbuxton]

I had my pool resurfaced with pebbles in July and am very happy with the results. I decided to actually take care of the pool this time and turned to Trouble Free Pool. I use a SWG which I love and added borates which gave me a soft feel and super clear water.

The problem I'm having is with acid demand and the problems it brings. Both TA and CH tend to climb out of their range. I built the three headed sprinkler I found on your site and have used it and acid to lower the TA. You will notice from the numbers below that I need to do it again.

The Chemical Hardness in the water started at 220 and has climbed to 475. The CSI index is -0.47. Everything I read says I need to remove about a third of the water from my pool and refill. Since that will change the levels of almost everything in the pool I want to be sure that is the only option.

Thanks for your help and great site.

FC: 6
CC: 0
PH: 7.5 today 8 in two days
TA: 100
CH: 475
CYA: 80
Borates: 50

 

[dmanb2b]

Welcome to TFP

Take a read through the below post...very similar to your situation. Only way to lower CH is partial drain and fill or reverse osmosis treatment, but your CH is not high enought to warrant the cost of a RO treatment IMO.

fighting-scale-and-high-ph-in-pebbletec-swcg-pool-t54118.html

 

[ping]

I'm not sure how you are getting a CSI of -.47 with those numbers. Salt and temp have some bearing on the CSI and you did not list those. In your situation, the calcium is only helping to make the CSI +. You will most likely have to live with your pH swinging rapidly for a year, then it should start to slow down. Hopefully the pH swing will slow down with the cold water this winter.

 

[UnderWaterVanya]

I'm not sure how you are getting a CSI of -.47 with those numbers. Salt and temp have some bearing on the CSI and you did not list those. In your situation, the calcium is only helping to make the CSI +. You will most likely have to live with your pH swinging rapidly for a year, then it should start to slow down. Hopefully the pH swing will slow down with the cold water this winter.

Just for grins I added all this into Poolcalculator and if I set the salt 3500ppm and the temp to 41 degrees I can get the same CSI. With salt at 4500ppm I get this result at 44 degrees. With salt at 3000ppm I need the temp to be 38 degrees. I'm not sure where the OP is but these seem pretty crazy temps to me.

I did notice that at a pH of 8 - the CSI index was better with the low temps - as the temp climbed the index eventually could go too far and indicate scaling potential.

 

[wbuxton]

I adjusted the PH down to 7.6 and took a new set of readings.

FC: 6
CC: 0
PH: 7.6
TA: 75 (back into range)
CH: 425 (still too high)
CYA: 80
Borates: 50
W/T: 85'
Salt: 3000

I used the Taylor Watergram Calculator and got a CSI of 0.2 while The Pool Calculator says 0.28 and recommends replacing 29% of my pool water with 0 CH water. My tap water has a CH of 125 so I may be looking at replacing half the water in my pool. I'm about ready to turn off the solar heat for the winter. Lower water temperatures (60'f) would lower the CSI index to 0.0 which I think is the goal.

Question: Can I hold off replacing the pool water, which is expensive, by lowering the water temperature. We get lots of free water during the rainy season. I'm quite willing to replace the water now if there is a good chance of damage to the pool surface or equipment.

Thanks

 

[duraleigh]

If that was my pool I would do absolutely nothing but lower the pH down to around 7.2 - 7.4 and monitor it to keep it there. The CSI is seldom useful to most pool owners and if you simply keep your parameters within the guidelines we suggest (you're close already, and you say you can dilute your CH by rainwater) then you will never have a problem.

You don't say where you live but I assume you know what "lots of freewater" is to reduce your CH to below 400