Hello and thanks. I just noticed a big drop in salt and CYA and I'm asking for help with interpreting what I'm seeing. This is a new pool with a cartridge filter and I have never drained water. 320lbs of salt were added on 9/28 and the SWG was started. I'm testing with the Taylor 2006C+Salt kit and I picked up an Apera pH meter. Salt was 3400ppm on 9/29 and sat at 3200ppm for the next 2 weeks. I targeted a CYA of 70, and I generally floated between 65 and 70 (I hate that cloudy water test - I don't trust myself to get the correct results). Since both seemed to be stable I resigned to checking it just once a month; with near daily pH and FC tests. Yesterday I decided to test CH, Salt since it had been WELL over a month since the last tests for those.
Test results from 12/4 @ 12pm, water temp 55F
pH = 7.9
FC = 7
Salt = 2600
CH = ~325
CYA = 55
TA = 60
I did NOT expect the CYA nor the salt to drop, so I took a sample to my local pool store. They use the BioGuard water analysis (mini centrifuge looking device).
Their results:
pH = 7.9
TA = 60
CH = 333
FC = 6.4
CYA = 43
Salt = 2300
I'm ALWAYS paranoid that we have a leak. I have to add 1-2 inches of water every 5 to 10 days. I really thought that would slow down during the colder weather, but it's about the same as what I was adding in August/Sept. These forums say that 1/4" / day is average AND evaporation is a function of surface area and wind not temperature. I thought that the CYA and Salt would NOT change since I don't have to backwash, but the pool store guy said that all the chemicals will come out with evaporation - I didn't want to challenge him on that, but doesn't most of our salt come from evaporation pools that rely on water to evaporate and the salt to stay behind? Anyway. What has changed in the last month is the temperature, it has dropped significantly. That has caused the freeze protection system to kick in and run our sheer decent for long periods so I'm assuming that has impact the evaporation rate. I don't see soft / wet spots between the pool and equipment pad. We haven't had the sod installed yet (it comes tomorrow) so I would assume a leak large enough to affect the water chemistry would be apparent by now. No one has been swimming for well over a month, so there's been no spash-out.
Here's the final piece - the CH hasn't changed. We have a pebble finish, but I don't know how much that will contribute to the overall CH. Is the stable CH a sign that there is no leak?
I made some additions yesterday:
16oz CYA powder - nylon skimmer sock tied in a knot
40lb salt - semi dissolved in a bucket, then brushed in
4lb Calcium - dissolved in a bucket
36oz Baking soda - dissolved in a bucket
Today's (12/5) test results AFTER vacuuming and brushing
pH = 7.6
FC = 8
Salt = 2800
TA = 75
CH = 330
CYA = 60
The last 3 days have been in the 70s here - before that we had 3 weeks of 50s/low 60s. I don't know if the FC jumped because of the salt or because of the water warming a bit. I expected the CH to jump more after adding 4lbs. I'll keep a close eye on it over the next few days, but I'd like a sanity check from the forum if anyone will share their opinions. I read two internet articles that said I SHOULD expect to add a few bags of salt every year, even though I don't backwash, because the salt breaks down over time (which doesn't make sense; I thought it collapsed back into NaCl once the CL was done with oxidizing). Same for CYA - does it break down over time?
Test results from 12/4 @ 12pm, water temp 55F
pH = 7.9
FC = 7
Salt = 2600
CH = ~325
CYA = 55
TA = 60
I did NOT expect the CYA nor the salt to drop, so I took a sample to my local pool store. They use the BioGuard water analysis (mini centrifuge looking device).
Their results:
pH = 7.9
TA = 60
CH = 333
FC = 6.4
CYA = 43
Salt = 2300
I'm ALWAYS paranoid that we have a leak. I have to add 1-2 inches of water every 5 to 10 days. I really thought that would slow down during the colder weather, but it's about the same as what I was adding in August/Sept. These forums say that 1/4" / day is average AND evaporation is a function of surface area and wind not temperature. I thought that the CYA and Salt would NOT change since I don't have to backwash, but the pool store guy said that all the chemicals will come out with evaporation - I didn't want to challenge him on that, but doesn't most of our salt come from evaporation pools that rely on water to evaporate and the salt to stay behind? Anyway. What has changed in the last month is the temperature, it has dropped significantly. That has caused the freeze protection system to kick in and run our sheer decent for long periods so I'm assuming that has impact the evaporation rate. I don't see soft / wet spots between the pool and equipment pad. We haven't had the sod installed yet (it comes tomorrow) so I would assume a leak large enough to affect the water chemistry would be apparent by now. No one has been swimming for well over a month, so there's been no spash-out.
Here's the final piece - the CH hasn't changed. We have a pebble finish, but I don't know how much that will contribute to the overall CH. Is the stable CH a sign that there is no leak?
I made some additions yesterday:
16oz CYA powder - nylon skimmer sock tied in a knot
40lb salt - semi dissolved in a bucket, then brushed in
4lb Calcium - dissolved in a bucket
36oz Baking soda - dissolved in a bucket
Today's (12/5) test results AFTER vacuuming and brushing
pH = 7.6
FC = 8
Salt = 2800
TA = 75
CH = 330
CYA = 60
The last 3 days have been in the 70s here - before that we had 3 weeks of 50s/low 60s. I don't know if the FC jumped because of the salt or because of the water warming a bit. I expected the CH to jump more after adding 4lbs. I'll keep a close eye on it over the next few days, but I'd like a sanity check from the forum if anyone will share their opinions. I read two internet articles that said I SHOULD expect to add a few bags of salt every year, even though I don't backwash, because the salt breaks down over time (which doesn't make sense; I thought it collapsed back into NaCl once the CL was done with oxidizing). Same for CYA - does it break down over time?
CYA is a bit finicky to test, so even if you thought it was 70 before, perhaps it was slightly lower already. Then it dropped about 3 - 5 ppm per month from there. Maybe. Salt testing also comes with some variations. As much as we like accuracy, the salt test can vary by about 200 ppm as well, and mine never matches what my SWG shows for a saline level.
