Lots of Rain = Chemical Waste = Need to test everything more frequently

sehrmude

Bronze Supporter
Aug 21, 2017
192
Tampa, FL
***This is just a story of my learning experience - If you are new to maintaining your own pool, like I am, make sure you retest ALL of your chemical levels after periods of heavy rains.***

Before the pool build was completed, I had used my TFTest kit to figure out my fill water (tap). I read a lot in the pool school section and received solid advice from the group here - I started maintaining the pool on my own in May and quickly put that advise to good use and began understanding the effects of chemicals and how my particular pool responds. I know how much MA to add to adjust (.x) pH - how long to run the pump at (x)% output from the SWCG to get the desired chlorine and I know the effects of running the sun shelf fountain airation of the water) on pH. I've tested and added salt and CYA after the rain...realizing that these things do not exist in rain water...but I failed to re-test the Calcium Hardness.

I had just added salt and CYA prior to going on a month long work trip.

We had ~14" of rain while I was away.

Upon returning, I ran the regular tests and needed to add salt (was down to 2700 from 3600) and CYA (was down to 40 from 80). These were significantly higher drops in levels than I expected in just 30 days...

This time I measured the CH and it was at 180 (15 drops to turn blue). The last time I tested CH it was in June and it was at 408 (34 drops). Confused, I retested the next day...this time I got 168 (14 drops to turn blue). I ran the test again and 14 drops was confirmed...I think the day before I was adding drops more quickly not expecting it to turn blue so quickly so that 15th drop was just 'extra'.

Pool math said I needed 23lbs of Calcium Chloride to adjust to 350 (my minumum level). I bought a 25lb box and slowly added about half the box over 2 days and then retested...CH 240. I added the rest of the box, some Saturday and some Sunday.

It's been an unusually wet summer here in Tampa, FL - even with record high temperatures I have never needed to add water to the pool. The automatic overflow has kept the pool from flooding the pool deck.
 

an1vrsy

Bronze Supporter
Jul 10, 2018
250
Las Vegas, NV
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
@sehrmude, you may want to recheck the calcium hardness test kit instructions. When using the 25 ml sample size, the number of drops with R-0012 is multiplied by 10. When using the 10 ml sample size, the drops are multiple by 25.

So, aren’t your test results with 14 drops either 140 ppm or 350 ppm depending on sample size?
 

sehrmude

Bronze Supporter
Aug 21, 2017
192
Tampa, FL
@sehrmude, you may want to recheck the calcium hardness test kit instructions. When using the 25 ml sample size, the number of drops with R-0012 is multiplied by 10. When using the 10 ml sample size, the drops are multiple by 25.

So, aren’t your test results with 14 drops either 140 ppm or 350 ppm depending on sample size?

Thank you for that reply - I will certainly double check tonight when I re-test. I was reading the instructions while performing the tests - and writing this post from memory (using a calculator to reverse engineer the # of drops). I am hoping that it is my memory that was wrong and not my test results...otherwise I might be intentionally draining some water tonight.
 

sehrmude

Bronze Supporter
Aug 21, 2017
192
Tampa, FL
...and the verdict is....on my initial test I correctly multiplied by 25. After checking my notes at home, the initial test result was 175ppm. After adding half the 25lb box, I retested and came up with 216... If I multiplied by 25, this would be impossible....so I must have multiplied by 12. 18x12=216. 18x25=450. (I should have stopped here)

Reading the instruction sheet - there is an example at the end of the CH test instructions that says: 12x25 is 300......I guess this confused me and I used '12' instead of 25.

Fact is - now my CH is now at 600.

Just how BAD is 600 CH? Is this something I can wait a few days on, or should I be draining immediately??
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,343
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Input your test data into PoolMath and see what your CSI is. You want to keep it between -0.3 and 0 with a SWCG.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,343
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
That's fine. TA and pH will control your CSI with a constant CH. Water temperature has an effect also.

I would imagine you will get enough rain to lower your CH with time.
 

sehrmude

Bronze Supporter
Aug 21, 2017
192
Tampa, FL
Thanks mknauss. You and the rest of the TFP group are always really helpful! One day I will be able to give better advice!
 
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