Calcium in vinyl pools

[Fla Rizzo]

My latest set of readings following a big rain showed a big drop in my alkalinity and calcium.
My alk dropped by about 20% for which I am adding 3 lbs of baking soda.
My calcium dropped from 165 to 120, still in the range from the pool calulator (50-300) but in the pool school section a comment "In a vinyl lined pool there is no need for calcium" caught my eye.
Can I stop testing for calcium altogether since I have a vinyl pool?

Note: I have been following the BBB method and everyone is amazed by the sparkling water - thanks.

cl 5
ph 7.4
alk 60
cal 120
cya 30 and rising
74 deg F

 

[bk406]

You really dont need a lot. I keep around 50 ppm in mine just for water feel, really. I dont like the feel of really soft water and prefer a little hardness. I do have a chlorine generator so I do have sodium chloride at 3500 ppm, but I still like a little calcium to "harden up" the water a touch. My fill water has less than 10 ppm, so I do add a little every spring. Also, some heaters may require a little calcium to maintain a warranty, so that might be a consideration. But it terms of 200-300 ppm calcium like a pool store would recommend....not so much

 

[zea3]

If you live in an area where there are high calcium levels in your fill water then you want to to keep an eye on it throughout swim season. Vinyl pools can also develop scale when calcium rises too high. The main danger to plaster pools is when the calcium in the water drops too low, it will pull calcium out of the plaster. Over time this will cause damage and if left uncorrected will cause premature plaster failure.