new plaster

[deepnnet]

I've seen that new plaster releases alot of alkalinity and some calcium.
The water in my area is very soft. (about 50ppm calcium)
My questions are:1. Should I allow the plaster to cure 4-6 weeks before
adding calcium?
2. Am I causing damage to the plaster by doing so?
I've seen water come up to 200+ppm by the end of the cureing process.
3. Is this the right or wrong thing to do?

Thanks much,
Rick aka deepnnet

[mas985]

I am not clear as to what your current calcium hardness measurement for the pool is. If your calcium is already past 200 ppm then you are OK. Keep your PH down to 6.8-7.2 during this time and the plaster dust should contribute to the calcium.

[Simmons99]

Calcium will leach out of the plaster if the calcium level is below 200ppm - you don't want this to happen as it can damage the plaster. Yes - you want to get it to the 200-400ppm range.

[deepnnet]

Thank you for your responce. sorry for taking so long to reply,I've been
really busy the last couple of days.
Let me make the question more clear.
How soon after a new white plaster pool is filled (fill water @ 50ppm)
should calcium be adjusted? If left unchecked , the calcium will rise on
it's own during the 4-6 week curing process.(I've seen it go as high as 300)
Note: I do keep the pH low ~7.0 during this time to battle the rising
alkalinity.
Should I add calcium right after fill? will that halt further calcium release
from the new plaster? Or is the plaster going to release more calium anyway (low pH)
and possibly end up with very high levels at the end of the curing process
and possible scaling problems?
Thank you very much! Rick aka deepnnet

[mas985]

If this is not the first fill after new plaster, then I would go ahead and raise the calcium to 200 ppm.

If it is the first fill after new plaster, then I would drop the PH to 6.8-7.0 and after a 3-4 days, test the water and if the CH is still below 200 ppm and most of the plaster dust is gone, then I would add calcium.

Plaster dust can add quite a bit of calcium to the water and it is actually good to start a new plaster pool with a low calcium level since this will dissolve much of the plaster dust and save a bit of time vacuuming it out. Dissolving the pool surface due to low calcium levels is a very slow process so I would not worry too much the first week. But after that, if it is still < 200 ppm, then I would go ahead and add calcium.

[deepnnet]

Thanks Mark thats all I needed to know!
Rick