Winter startup - tracking chemical needs

[mknauss]

Raise your TA to 70 ppm with baking soda. Natural aeration will raise the pH.
I would wait on CYA. Not as critical right now. Let the pH come up first as the CYA will push the pH down a bit.

Use the FAS-DPD test for FC. No need to even do the OTO color match for FC.

 

[Auburn02]

Thanks @mknauss . Added all the baking soda I had (3lbs 6 oz) this morning which should raise the TA closer to 40 - I'll pick up more when I'm out later. Running the deck jets to help aerate and also stir up the baking soda a bit. One other thing I need to learn is how long after adding certain things can I expect them to show up in a test. For example if CYA may not show up for at least a day and maybe two, should I expect the same for all additions?

 

[mknauss]

should I expect the same for all additions?

Liquid chemical shows up in 30 minutes or so. Baking soda about the same. Calcium, salt, and cya can take more time to disperse.

 

[Auburn02]

New tests:
TA is right at 40 as expected
pH is now reading at 7.2 after adding that baking soda and running deck jets all day long.
FC is 4.5, CC is 0.0. My water temp is running about 52 and my SWCG will run down to 50 degrees so I haven’t had to add any liquid chlorine yet but I have it at the ready if the temp drops and the SWCG shuts off.

Might still make it to Costco this evening for another bag of baking soda and will add that tonight or in the morning.

 

[Auburn02]

Alright y’all at this point I’m just talking through my process, if any of this sounds off kilter just shout it out.
Today’s tests:
pH: 7.5-7.6
TA: 60
FC: 6.0

That’s all the measurements I did this round, last CYA measurement a couple days ago was 20, as far as I’m aware nothing should have changed that. Not sure if I should bother bumping that up for winter or just hold off til things warm up. I do have the acid on hand. No reason to suspect CCs at the moment, not sure if it’s common to still check daily or only when things seem “off.”

Up until this point the pump has been running 12 hours a day with the SWCG at 34%. I also ran the pump an extra hour or two last night to mix in the baking soda, so that could explain a bit more increase in FC perhaps? I’ve just rescheduled the pump for 9 hours a day and left the SWCG at 34%, will see what happens over the next day or so. I’m also still letting the SWCG run anytime the pump is running via flow switch, but I will put the start and stop lugs on the mechanical timer likely tomorrow to limit the SWCG to only be on within the pump’s scheduled run time. Long story short, I’m just experimenting at this point to see how different changes affect the FC, but it’s about to all go out the window the next cold snap we get and the SWCG stops generating and I have to go to liquid chlorine anyway.

 

[Newdude]

but it’s about to all go out the window the next cold snap we get and the SWCG stops generating and I have to go to liquid chlorine anyway

By the time the season starts for real you will be a pro at anything the weather can throw at you. Manually dosing soon will make you love the SWG even more in the summer when all it takes is a few clicks to raise the FC.

 

[ajw22]

I check CCs everytime I test FC. It takes only a few seconds and a few more drops.

CCs greater then 0.5 is your early warning sign of a poss problem before anything is visible. Often it just takes raising your FC level a few ppm to stop a problem from developing.

CYA of 20 is skirting on the edge with a SWG. Don’t let the warmer weather and longer days coming catch you by surprise with your FC suddenly dropping. Stay ahead of your pools rising FC needs.

 

[Newdude]

I check CCs everytime I test FC. It takes only a few seconds and a few more drops

+1. I open both bottles so it’s ready and put down the 0871 bottle and pick the other one up immediately. It doesn’t even have to be an accurate 5 drops for CCs as long as it’s over. 9 drops is still clear if 5 drops is. That one time that you have CCs go back and count the actual 5 drops so you don’t mess up the second dose of 0871. All the other times you won’t have CCs and you’re done.

 

[Auburn02]

Well our weather, as is typical down here, keeps teasing the SWCG into staying in operation. Pool temp actually climbed up to 57 after a few days in the 70s with lows only in the low 60s. So I've yet to have to do any manual dosing. In fact, my FC is still high. Trying to decide on just turning off the SWCG for a day or two, or turn it down some more, or just leave it be.

I still plan to add another 2-3lbs of stabilizer to inch the CYA up closer to 60-70, might do that today.

Full results from yesterday:
FC: 6.0
CC: 0.0
pH: 7.6
TA: 60
CH: 100
CYA: 40
SALT: 3000

 

[mgtfp]

I wouldn't call 6ppm FC high for CYA 40, that's smack in the target range for non-SWG, which I would apply in winter with the SWG kicking in only sporadically.

No need to actively force FC down, just be glad that the SWG can keep FC stable there with kicking in from time to time.

Not sure what others think, but I don't see a need to get CYA up to 70 in winter. Consider your pool a non-SWG pool for now (you don't get that SWG benefit of having regular "super-chlorination" within the cell with the SWG working only sporadically). I'd say, 40 is just right for know. Get it back to the SWG-range in spring.

Just sit back and appreciate that your pool is low maintenance for now (even though you might want a few more tasks around the pool to keep you busy during Covid...).

 

[ciaka]

Just before you start filling, record wayer meter reading (take pic).
Just after pool is filled, record water meter reading again(yes, pic is best).
Subtract ti get the difference. Then subtract what amount if water you would normally use in the fill time period. This gives you best estimate for your pool volume.

 

[Auburn02]

Long story short, I’m just experimenting at this point to see how different changes affect the FC, but it’s about to all go out the window the next cold snap we get and the SWCG stops generating and I have to go to liquid chlorine anyway.

I know everything tends to slow down in the winter and my pool is on the north side of my two story house and gets little sun right now, but I am astonished at how little chlorine it’s using. The pool temp dropped below the SWCG shutoff just after New Years and I ended up just turning it off completely a couple weeks ago, yet I’ve only added 42oz of 10% LC 10 days ago and my FC is still hovering around 6.0. I check it every two or three days expecting it to have dropped but it just keeps hanging in there. Will probably add another quart today to bump it up to 7-8ish (CYA is 60-70).

Not complaining, just fascinated.

 

[mknauss]

gets little sun right now

Little UV impact. So FC does not get used up.

 

[Auburn02]

I know everything tends to slow down in the winter and my pool is on the north side of my two story house and gets little sun right now, but I am astonished at how little chlorine it’s using. The pool temp dropped below the SWCG shutoff just after New Years and I ended up just turning it off completely a couple weeks ago, yet I’ve only added 42oz of 10% LC 10 days ago and my FC is still hovering around 6.0. I check it every two or three days expecting it to have dropped but it just keeps hanging in there.

Funny story, after posting this 5 days ago I did add 32 oz of bleach and measured my FC at 7.0. A few days ago the wife and I both remarked at how quickly the sun is "coming back" and thus hitting the pool more. Last night, measured again and FC had fallen in those 5 days from 7.0 to 4.0, when in a previous 5 day span early January it only fell from 6.5 to 5.5. This is probably no surprise to the experts, but very fascinating for me to watch it happen. Of course not just sun, we have also had a good bit of wind so more leaves in the pool the last several days, I suspect that is causing some of the chlorine to be consumed as well. Added another 2 quarts last night, suspect the measurement this morning should be around 7.5-8.0.

 

[Auburn02]

Ok things are really warming up here now and the SWCG is functioning so I suppose I need to transition from treating it like a non-SWCG pool to the SWCG pool that it is. With that said, I’m sitting at a CYA of 60 and FC of 7.5. I’ve read a number of threads and still can’t wrap my head around why the target FC is so much lower for a SWCG pool compared to non-SWCG given the same CYA level, something about it doesn’t need as high of a buffer I guess? In any event I have not added liquid chlorine in about 3 weeks and my FC numbers have been pretty consistent between 6.0 and 8.5 over that time. So I feel like my SWCG settings are good for the time being for day to day maintenance, but based on the chart for a SWCG pool my target FC should be 4, not the 7-9 I was previously aiming for. Should I just turn the SWCG off entirely for 24 hours and let it drift down and re-test or dial it down to reduce output over a couple days before bringing it back to the current setting? I guess either way works as long as I watch it and don’t let it fall below the minimum. I’ll also be adding just a bit more CYA to get that up to a solid 70 or 80.

 

[wireform]

I like the 7-9 for the FC especially if you're going to bump the CYA up some. Don't worry about the extra point or two of chlorine. You will never know it if you hadn't tested but the algae surely knows it's there.. You can watch it over the next few days and make small adjustments if needed but I'm not a believer of shutting it down.

 

[bmoreswim]

My FC is always above the SWCG range because, although the pool will be fine lower, it’s too easy to have it drift down below range with rising temps or a party. I like the safety.