Are these Levels OK?

[lovemyazpool]

Hey Everyone -

Some of you may recall that while using a pool company to care for my pool I had a runaway alage problem about 18 months ago. After testing the water a 100% drain and refil was completed, a new SWG system from AutoPilot installed and everything seems to have been going great. We live in Phoenix, stopped using to pool due to excessive low temps and just started to use it again.

As a result, I just kept an eye on the pH and ORP over the winter, not really testing the pool. I started getting weird stains and started testing again. So today my son and I ran the complete battery of tests and this is what I came up with:

FC: 1.5
CC .4
pH 7.2
TA 30
CH 450
CYA 0 (tested this three times, completely zero)
Borate 15
Salt 2600
Temp 72 F

SWG ORP Reading: 680

So looking at this post, it looks like an FC of 1.5 with a CYN of 0 is fine, and using Jesse's Graphical Pool Testing XLS also shows that FC as "in the green". I just don't want to get down the road in summer and figure out that I was wrong this whole time.

Also, I also see that my pH is a bit low, my CH is high and my TA is low. Are these super critical and should I get them addressed now or wait until the pool is put into use? Which ones should I address first (if any) as I am sure fixing them might adjust others...

Thanks

 

[Texas Splash]

I would recommend the following:
- While Chemgeek's thread is informative (and quite detailed as always), keep it simple and use the Chlorine/CYA Chart he linked (also in my sig below). As long as you manage your FC and CYA together on that chart, you will do well.
- Your CYA should never be so low. Even non-SWG pools operate best with at least 30 ppm for FC protection from the sun. With a SWG, your CYA should normally be at least 70 as recommended on the Chlorine/CYA Chart. Remember that chart was built by those very experts/scientists here at TFP. (see below before increasing CYA!)
- Because AZ commonly has hard water, CH will always be an issue. To compensate, it is not uncommon to keep TA and/or pH on the lowered end. You do that on purpose to avoid scale build-up. You can see that relationship and the effects of pH, TA, and CH on the Poolmath calculator - near the bottom row.
- Having said that, your TA itself is a bit low. I would never want it below 40. So I would simply increase TA to at least 40 or 50 and leave it there if the pH remains consistent.

By elevating your CYA, your SWG should work more efficiently and the FC should be protected better from the UV in your area. A slight increase in TA should help to buffer pH better and prevent any wild pH swings.

Final word or caution - If you think there is ANY possibility of algae (green, cloudiness, etc) or excessive FC consumption from starting things up this year, only increase CYA to "30", and be prepared to do a SLAM (link below) by increasing FC to 12. If you're not convinced about algae, increase FC to about 6 or so and perform an overnight (OCLT) test. It's best to rule-out algae while the CYA is at 30 (less bleach for a SLAM) rather than to get your pool all ready for the SWG-season only to find out ... "oops, I have algae", and have to SLAM at that higher bleach requirement.
This statement concerns me:

I started getting weird stains

Those might be organic/algae stains. You might want to test according to the TFP Pool School - Metals in the Water and Metal Stains page first.

Hope that all makes sense. If you have any questions, just let us know.

 

[lovemyazpool]

Thanks Texas Splash -

I did the test and determined the stains to be iron based on the test. I need to order one of the specific test kits, but putting Vit. C on it as suggested caused the stain to lighten up.

Based on the reading here and your suggestion I think I will add additional salt to bring my salt up to the 3200ppm mark which is in the recommended range by my SWG system, then bring up the CYA to 70 as suggested. I will add 24 lbs of baking power to bring my TA up to 70 to 80 then let everything set for about a week. I'll report back!