Converting to SWCG--Chemistry Questions

[911medic]

After years of doing TFPC/BBB on my various Intex AGPs with bleach, I've decided to convert to a SWCG this year, along with a sand filter system. My Intex 633T filter pump has run great, and is certainly an upgrade from the one that came with the pool, but the cartridge maintenance just gets really old.

Anyway, here's what I've purchased:

• The largest Intex sand filter (3,000/2,450 gph)
• The new 15,000 gallon Intex SWCG (no copper plates)

We have well water with clear water iron in it, so I fill my pool with water that has been run through my water softener to remove the iron (otherwise, adding bleach to my hard water causes the iron to immediately precipitate out of the water and makes my pool look like a mud bath). As a result, my CH numbers are pretty low. Also, our well water is very alkaline.

Typically, my soft water CH runs <10 (solution starts out purple--not red--and one drop of R-0012 turns it blue), and my TA usually starts the season around 380-400.

So, my questions as I begin to prepare for installing the new equipment this spring are:

• With my TA typically so high, how aggressive do I need to be about lowering it? The "Water Balance for SWCGs" article states that TA between 60-80 is "IMPORTANT."
• With my CH so low, do I need to bump it up? The same article says CH for vinyl lined pools should be between 50-300, but also says, "don't add."
• If I need to adjust these things, do I need to do so BEFORE firing up the SWCG? Should I just go with bleach until the water is balanced for my SWCG?

Thanks for any help you can provide!

EDIT: Also, this year, for the first time, I left the pool up over the winter. Which means I'm carrying over a little less than half of my water from last year. As a result, my TA will probably start out a little lower, as splashing/adjusting pH with MA over the previous summer lowered the TA in the existing water.

 

[cowboycasey]

You will love a SWG

The only issue I see is your TA, with it that high your PH will raise very fast, how fast is the question and you will need to keep up with the PH test.. So I would take your TA down using these directions Pool School - Lower Total Alkalinity

I would add the salt and use bleach till you get close to the recommended setting before you fire up your SWG, then turn it on and monitor and see what your pool likes

Hope this helps

 

[911medic]

You will love a SWG

The only issue I see is your TA, with it that high your PH will raise very fast, how fast is the question and you will need to keep up with the PH test.. So I would take your TA down using these directions Pool School - Lower Total Alkalinity

I would add the salt and use bleach till you get close to the recommended setting before you fire up your SWG, then turn it on and monitor and see what your pool likes

Hope this helps

Thank you, Casey. OK, I'll plan to do my hard-plumbing of the system first, so I can install a fountain for aeration purposes, and work on lowering the TA before starting the SWCG. Or did you just mean to do the typical prep before starting the SWCG (adding salt, of course, and getting up to the recommended chlorine level with bleach)? I did plan to do that.