SWCG Conversion Howto? Recommendations?

[Pegasus_RPG]

Hello everyone.

After reading tons on this site, and considering the fact that I live in a desert, I'd like to install a SWCG. But I couldn't find a conversion howto, so does that mean the installation manuals tell everything I need to know?

I've been using 10% sodium hypochlorite the past couple weeks, and a lot of it (about a gallon every other day) once I realized the tablets I was using in a floater were evil had sent my CYA off the charts. (Pool store test.) So my sodium level is likely already elevated. I have a new TF-100 on the way along with some salt test strips to find out for sure. The pool store also said my CH is getting up there, 380ppm as of last week.

I plan to self-install. I've worked with PVC and electrical many times before so no fear there. My plan is:

1. Test replacement water from automatic filler with TF-100 (for CH and salt especially.)
2. Wait until the intense sun cooks CYA down to 80. (Should I maintain this level with a SWCG given the climate? 100+ degree days for 4 months of the year, pool open year-round.)
3. Check CH & salt levels. Add salt/replace water if needed. (I have no waste piping so what's the best way to drain water? Via the high-flow PR valve on the filter into a bucket hundreds of times?)
4. Install SWCG inline after heater, wired to mechanical pump timer.

Does anyone have any recommendations for particular brands/models of SWCG? I'm planning to replace my pump very soon with a VSP, so I'll be essentially bypassing the mechanical timer and would need the SWCG to tie in to the pump's control module somehow to prevent powering up when the pump is off.

Thanks so much for your help!

 

[jblizzle]

1. Sure
2. What is your CYA currently? May take a long time to lower the CYA in the method you suggest. Much faster to replace water (and it would lower the CH)
3. While you are considering plumbing, add a 3-way valve between the pump and filter to give you a waste option. If not, rent or buy a submersible pump.
4. Will need to plumb in the cell and likely a flow switch, follow the straight pipe length recommendations in the manual. Power the SWG on the same timer as your pump (oops, see below)

So you can use a current sensing relay to power the SWG when the VS pump is running. Or make sure your mechanical timer runs the SWG only during the time when the pump is running.

Size at least 2x the size of your pool. 40k cell would be minimum and given your location, I would suggest a 60k cell. Circupool or Pentair offer them in this size.
If you might go with a Pentair VS pump and consider an automation system, get the Pentair. If not getting automation, the Circupool is usually cheaper to buy and replace cells.

 

[mknauss]

Your CYA will take a very long time to drop that much. I lose about 10 ppm per month during June to August. Then nearly nothing the rest of the year.

I find the pool store claiming your 380 CH is 'getting up there' laughable. You start at over 250 ppm if you are using LVVWD water. And with our evaporation, it will only take a couple months or so to get to 380 ppm.

With a single speed motor, you want a SWCG rated for 60K. You will still need to run your pump for 10-12 hours per day during the summer to make enough chlorine. Start considering a VS pump in the near future.

 

[Pegasus_RPG]

My current CYA is over 100, probably 150. (The tester maxes at 100.) Yeah, if it only drops by 10ppm a month then replacement is the only reasonable option. (How can I figure out how much I need to replace? Or will the TF-100 instruction sheet explain it?)

As for SWCG selection, the Circupool units look good. Is there any reason to prefer the RJ series to the SJ other than longer service life? (Figuring the 55K vs 60K isn't enough to worry about.) Better flow I suppose due to the design differences?

And yes, I'm just about to order a VS pump as well.

 

[jblizzle]

Look at the extended test instructions in Pool School. There is a way to do the CYA test with diluted pool water to get a better feel for your high CYA level.
The CYA reduction is directly correlated with the amount of water you replace. Replace 30%, reduce CYA by 30%; replace 50%, reduce CYA by 50%