New Pool, CL dropping fast, SWG not working?

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H

Hagefamily

Well-known member
Jun 4, 2012
78
I need some help figuring out why I can't keep my chlorine levels correctly.

Pool is brand new. Started construction last year and finished it this Spring.
Here was my test results last week:
FC=3.0
TA=70
CYA=75
PH=7.5
CC=None

I added about 3 quarts of bleach to my pool to raise the FC level to 5.5. I figured that raising it quickly would then make it easier on the SWG. I tested the water that evening and again the next day. I had the same results both times:
FC=5.5
TA=70
CYA=75
PH=7.5
CC=None

I also had the SWG @ 50%, pump running 12 hours (8am-8pm), and waterfall running the full time.

I added water last night. Nothing major just normal evaporation/splashing type of loss. Filled it for about 90 minutes.

Today, the pump comes on at 8am set for 50% SWG & waterfall is running. We are lucky to have sun on the pool from nearly sunrise-to-sunset. The temperature of the pool has been averaging around 80 degrees since June.

Around 7pm I decided to test the water using the basic test and the chlorine drop test. Same result = 3.0.
The first time I ran the drop test I came up with a 'barely' pink color on the CC test.

I figured I must have made a mistake because the FC dropped from 5.5 to 3.0 in 24 hours.

I tried the drop test again. The FC = 3.0 but no CC detected this time.

Pool is vacuumed, baskets empty, and the pump basket is clean too.

Here are my questions:
1. What caused my FC to drop? (Adding water? Too much sun? Algae?)
2. More importantly, why isn't my SWG raising the FC? <--How do I know if my SWG is working or not? [The Aquapure Panel isn't showing an error messages]

Thanks for your help!
 
When the FC level is too low, turn up the percentage on the SWG. If the FC level is too high, lower the percentage on the SWG.

This kind of adjustment is normal. Right at first you should test and adjust the SWG every two or three days. But once you get it setup just right you can slow down to once every week or two.
 
I forgot an important piece of information. The reason I added bleach to raise the FC was I couldn't get the level to rise even at 100% SWG.

That's why I'm thinking it may be the SWG. It seems that whether I set my SWG at 50%, 75%, or 100%, the FC stays around 3.0. I've been as high as 3.5 and as low as 2.5.

I put the bleach in to raise the level figuring the SWG would then provide enough FC to keep the same level.

If it matters, my salinity is at 3.0.

What's the best way to know if my SWG is working properly if the control panel isn't showing any errors?
 
Did you run it at 100% for two or three days? If not, you haven't really seen what it can do. SWGs add chlorine s l o w l y . Don't expect it to raise the FC level several ppm in a day, it isn't designed to do that.

It is clearly working. If it was broken FC would go to zero in just a few days.

There is a remote chance you have a low level algae problem, but nothing you have said suggests that might be happening. If you are worried about it, do an overnight FC loss test, see the instructions in the How To section of Pool School.
 
As I read through this, I keep thinking algae. Once algae gets going, your SWG can't keep up. I've seen it many times, where a pool will suddenly have low FC, and I turn it up 10 or 20% and the next week, its low again, and I turn it up again, until the SWG is maxed out, and the FC remains low. The algae is rallying the troops and getting ready to wage war on your pool. I would SLAM before it has a chance to go any farther. If you deal with it early, its usually easier to fix.
 
Thank you for the guidance. We're going to start with the overnight FC loss test.

Tonight, our FC is 2.5, CC 0.5

I'll test again early morning to see the difference. I'll post the results here.
 
when i thought i had a problem with my swg the pool shop advised
if the cell is in a clear pipe see if you can see water get cloudy/tiny bubbles
take a water sample from the return jet to the pool and measure free chlorine there ( mine was 1.2ppm more than rest of pool) indicating cell was functioning ok
as mentioned usually a sign you are about to turn green, mine went cloudy
also for a cya of 70 your fc is not high enough
 
This morning my FC=3.0, CC=None. No drop overnight. That's good. No algae, right?

Perhaps I should calculate how much bleach to add then & see if it maintains that level or not over a few days with the SWG running?
 

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We tested the water again today.

In one test we took water coming from the return while the pump & SWG were running. The result was FC=3.5.

Then, we tested again in an area of the pool away from the returns. The result was FC=2.5.

Pool is clear & clean. Vacuumed, scrubbed, baskets cleaned, pump filter cleared out, etc. Checked under the ladder but that's all crisp & clean too.

I'm thinking that I may have been fiddling too much with the settings. When the pool builder set it originally, the SWG was at 80% running 12 hours/day. Yes, I know that is probably too much but the FC rose to over 10 which is why I started changing the percentage & reducing the pump time.

I'm adding bleach to bring it back to the correct FC level & setting the pump runtime and SWG to 80% again. Then, I'll test every couple of days to see what happens.

If that works, then let's chalk it up to new pool owner error. If not, I'll be back to talk about some of the OCLT and other options folks suggested.
 
Using PoolMath I get that you were adding 1.1 ppm of chlorine to the pool with 12 hours run time and 50% on the SWG per day. I would bump the SWG up to 100% and longer run time and raise the FC to 6 ppm with bleach and see how it does.
 
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Not sure where the myth started that the FC needs to be at SLAM level to do an OCLT. As long as it's in the recommend range for your CYA a level of 4 or 5 is fine. The key is the SWG must be off and that you are testing in the same place every time. Also it's best to turn the SWG off a bit before doing the first test to make sure that's not giving a higher reading initially. As you probably have determined it may have been too drastic a change... just scale it back slowly till you get the desired FC Level you are seeking.
 
For me the trick was finding how long to run my SWG to replace the FC I lost during the day
after all thats the real purpose of the SWG
It will vary depending on the conditions, such as sun exposure and Solar cover
I run my unit 5 hours a day and maintain a FC of 4 to 5

You mentioned that when you started the SWG was @ 80% for 12 hours and you had an FC of 10
I think you reduced the run time tooo much
again if you want a FC of 6 and you bleach it to that level, run the SWG for 8hrs at 50%, test the next day if the Fc stays at 6 you are on track, if it has gone up to like 7 then back it down a little, but make smaller adjustments
 
Ok, so we changed the settings the night before last. So the full day yesterday we had the pump on for 12 hours (8am-8pm) and the SWG @ 80%. Yesterday around 11am, we used the Pool Math to add bleach to bring the FC to a 6. We did a quick vacuuming for a few leaves and a bit of sand, then waited a few hours for it to thoroughly mix. Yesterday mid-afternoon (around 4pm) we tested the FC and had a reading of 6 with 0 CC.

Just did a test now (12:45 pm) and got 6 FC, 0 CC. (For reference, CYA was 70, but didn't test that again.)

So it looks like we are on the right track.
We will test chlorine and ph again tomorrow and see where it goes.

https://flic.kr/p/nZx5t5
 
I'm doing the same thing as you, trying to dial in my cell. Right now, I am just doing the % deal, in increments of 10%. Right now I am in the middle of testing for a week at 60%. After this, I will start testing using less run time, a half hour at a time. My FC is staying at 8.0 ppm and has stayed that way since I put in my new cell at the beginning of June. Started at 90% cell and have taken all of a month's time plus some to mess with the numbers. Finally got into a pattern and will mess with the run time next for a full week's test time. Then chop it down in half hour increments to get it to my desired FC of 5. Still learning...

My numbers now:
FC- 8.0
CC-0.0
TA-80
CYA-70
CH-275
PH-7.7
Borates-50
Salt-3,400

I have a notion of putting in about 50-75 Calcium up to get that number up so that I can solve a white mark along the whole circumference of the pool. If I can do that, My CSI number will come down to a constant -0.20 and below, exactly the last number I need to solve.
 
Hi again... More readings from the pool.
So yesterday's noon reading was 5.0 FC and 7.5 pH.

Today was 3.5 FC when taken in the deep end sort of away from returns and 4.5 from the shallow end, somewhere between the returns, not directly in front of them. 0 CC on all readings.

We now seem to be going in the wrong direction.

Haven't changed the settings yet. The pump is on 12 hrs a day and SWG at 80%. The pool temperature has been 79-82 degrees F. And we're back to worrying about it, since the chlorine level is still drifting down.

Is it too soon to bump it up to 90%? Also, Doesn't running 90% for 12 hours seem like too much? I read other owners running the pump for 4-5 hours a day, at a much lower percentage. Our pool is nice sized, but is it really so big that a SWG rated for 40000 gallons can't keep up unless maxed out? I would think maybe it was undersized, but... It seemed to more than keep up just a few weeks ago when the chlorine had registered over 10 and was going up 2 points every day. So it just seems weird to me that now it can't maintain it at that same percentage. The air temp is a bit warmer since last month, not record breaking. And the pool temp is only a few degrees warmer than it was. It was around 76-78 those weeks, now it's around 80-82. Could those few degrees make that much difference? Is it that sensitive to conditions?


Another question... Reading the forum, people are mentioning tiny bubbles from the returns. I've seen small bubbles... Sometimes. We had discussed them and thought it was just a bit of air in the lines, now it sound like they are normal, a by product of the SWG. But we haven't seen any lately.

Should I be seeing them? Could that indicate a problem?

Again, crystal clear water, we're talking sparkly water. Our only clue something isn't right is the FC level. The only time we had CC's was after big rains and a few leaves in the pool, we got .5 CCs.

But could there be algae somewhere eating the chlorine anyway? Which is why the SWG doesn't seem to be keeping up? The last thing I want to do is add so much bleach to bring it to shock level and maintain it there. Our CYA is 70, so that's a lot of bleach to put in the pool. There already isn't a lot of swim time in NJ, and we have 3 young kids. 2 with asthma, 1 with eczema, which was one reason we went with the SWG in the first place. Obviously, if we have to, we have to, but only if we have exhausted any other options.


Thoughts?? Suggestions?
 

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