Re: Winterize in Southern California
On the 16th I added 1 gallon of muriatic acid. Today I tested & got these results:
FC=2.8
PH=7.8
Alk=90
CYA=120
CH=620
So I added another 1/2 gallon of muriatic acid. My PH is down to 7.2 but do I need to deal with the hardness? My fill water only 150. I have a feeling it's time to drain half the pool. Ouch.
Do I need to deal with the CH & CYA?
Thanks,
Kirk
Re: Winterize in Southern California
You will need to do a partial drain/refill to lower the CYA level at some point but as to whether you do that now or wait until spring is up to you. If you don't do it now, then you should keep your FC level higher to prevent algae growth. The usual rule for an SWCG pool is an FC that is around 5% of the CYA level so around 6 ppm as your target. With the water getting cooler, algae will grow slower anyway, but then chlorine will kill the algae more slowly as well.
As for the CH, the calcite saturation index with your numbers before you added the acid is around +0.3 which isn't too bad for causing scaling in a manually-dosed plaster pool, but it would likely have you get a lot of scaling in your SWCG cell. However, as the water gets colder, your SWCG will probably shut off and you'll be manually dosing the pool over the winter. So whether you do the partial drain/refill now or later is up to you. If it were my pool, I'd probably do it now just to avoid any scaling issues if I got lax over the winter and the pH went up too much, but that's just me.
Re: Winterize in Southern California
Chem Geek -
You've confirmed what I thought I would need to do.
I'm unsure of the best way to drain. Should I drain as I add fill water or do I actually drain to just above the basket and then add fill water?
Thanks
Re: Winterize in Southern California
Draining to just above the basket and then adding fill water will work, but it will be very slow. Assuming you're wanting to drain 1/2 the water, I would say 3 or so drains of 1/4 would work. Otherwise, I've seen reference to the "sheet method" (can't remember if it's CarlD or Poconos that has used it) where you put a sheet of plastic on top of the water and drain from under the sheet as you fill on the top--it's supposed to keep the chems in the top and bottoms from mixing.
Here's an old thread that talks about the sheet method--see ChemGeek's reply toward the bottom of the thread..http://www.poolforum.com/pf2/archive...hp/t-6121.html
Re: Winterize in Southern California
I've done an in-place refill before without using a sheet. The key is to introduce water at one end of the pool without too much mixing (pump off) while at the same time, remove water at the other end of the pool, preferably the deep end via a siphon. I have replaced over half the water this way and the result seemed to work without too much mixing (i.e CH dropped as predicted).