Newbie - need help or reassurance during SLAM

[crimson avenger]

Our fiberglass pool just got up and running last Monday. It sat filled with less than desirable water as you would expect for a fiberglass install. I would throw a couple cups of bleach every day and distribute it with our net.



Our pool builder threw in a gallon of chlorine when it started up and we started swimming once the chlorine reached normal range, and I started learning about chemistry and still have a ton to learn. Salt added this weekend and SWG seems to be working well.



Couple of observations:



I think my pool volume is actually closer to 2000 gallons. I back calculated the volume based on my salt concentration and CYA concentration. our 10 x 16 pool has a large bench around all sides as well as stairs. So you can’t use the typical volume calculator. This would also be corroborated by the fact that I overshoot with my chlorine additions every day. So my first question is – is this a reasonable way to calculate volume?



I am observing a daily loss of about 15 ppm of chlorine each day over the last two days. The pool is totally clear and it has been very sunny. Our pool is in full sun for about 8 hours. About 2 to 3 ppm happened at night as I have performed two overnight chlorine loss tests. My CYA is 60 but does it need to be higher if I’m losing so much chlorine in the day?



I am brushing and vacuuming every day. Today’s the first day of my SLAM - I added chlorine to get to 24 ppm per the pool math app and am going to use the SWG to generate 15 ppm chlorine to hopefully keep it at SLAM level based on my daily chlorine loss.



Am I missing something?



See my pool math logs for details. Happy to post them separately if desired.

 

[ajw22]

CYA 60 your SLAM Process FC is 24.

You want to keep your FC at 24 or return it to 24 as soon as your test finds it below your SLAM FC target. Your SWG cannot do that and does not let you judge your progress and FC loss. Turn off your SWG and use liquid chlorine during the SLAM Process.

Brush the pool at least twice a day to break up the biofilm protecting the algae.

Just test FC and CC during the SLAM Process. pH is not valid when FC over 10 and you should have lowered it to 7.2-7.4 before starting the SLAM FC level.

 

[crimson avenger]

CYA 60 your SLAM Process FC is 24.

You want to keep your FC at 24 or return it to 24 as soon as your test finds it below your SLAM FC target. Your SWG cannot do that and does not let you judge your progress and FC loss. Turn off your SWG and use liquid chlorine during the SLAM Process.

Brush the pool at least twice a day to break up the biofilm protecting the algae.

Just test FC and CC during the SLAM Process. pH is not valid when FC over 10 and you should have lowered it to 7.2-7.4 before starting the SLAM FC level.

Yes I lowered my ph to 7.2 prior to starting.
I have an IC20 which is rated for 20k gallons and my pool is only 2k.It’s only running 14 hours at 60%.Should I still just use bleach?

 

[ajw22]

Yes, use liquid chlorine. Using the SWG will likely make the SLAM Process take longer than necessary.

 

[Mdragger88]

You’re losing so much because something is growing. Your Overnight Chlorine Loss Test was the proof of that. When done with the SLAM Process you may wish to retest & increase cya to 70. Like @ajw22 said you must slam based on the FC/CYA Levels with liquid chlorine using PoolMath until u pass all 3 end of slam criteria.
the more frequently u test & raise fc back to 24 the faster it will go.

 

[crimson avenger]

Finally at SLAM level
By my calculations my pool has burned through 35 ppm chlorine in the last day based on the pool math calculator.
I rechecked my CYA and it’s a very likely 60 each time.
I’ve read so much about this process and it seems natural to feel unsure of ones’ self. Yes I’m using my SWG to augment the process - please don’t give me too hard of a time.
Seems like the chlorine requirements keep going up, not down. My pool is clear, only a little bit of fine dust which I am vacuuming up which I assume most people would call algae.
Brushing and vacuuming twice a day. The only good news is my CC is 0 for the first time.
Am I missing something?

 

[Mdragger88]

Just test & add as often as u can - every couple of hours so u can stay on top of the algae. You’ll see less & less fc loss over time. You’re beating it into submission! When your ready to do an Overnight Chlorine Loss Test you must turn off the swg otherwise it won’t be accurate.
Clean/backwash your filter when pressure is 25% over clean pressure. Slam on!

 

[crimson avenger]

Just test & add as often as u can - every couple of hours so u can stay on top of the algae. You’ll see less & less fc loss over time. You’re beating it into submission! When your ready to do an Overnight Chlorine Loss Test you must turn off the swg otherwise it won’t be accurate.
Clean/backwash your filter when pressure is 25% over clean pressure. Slam on!

Looks like my chlorine loss is decreasing MARKEDLY. So I think we are getting somewhere. I think my CYA level might actually be 70. I ran the control and it seems like I was waiting too long to call the result. Maybe my eyesight is superhuman??
New question- why is my CC still high at 1.5? I would think the CC would go down if I’m not losing any more chlorine.
I thoroughly wash the cylinder and speed stir before testing. I rinsed the cylinder with bleach yesterday. Thoughts?

 

[Mdragger88]

I see from your poolmath logs that you’re using your swg to maintain your fc - that can be problematic when trying to measure consumption as every cell is different & has different factors to consider like age, salt level, scale etc.
the poolmath app just lists those outputs as a “guide” to help you dial a swg in & figure runtimes under normal conditions.
I suggest u turn the cell off & dose manually w/ liquid chlorine to get a true understanding of fc loss @ this point - it is likely masking your fc loss simply because u have an oversized cell.
C.c.’s are there because the chlorine is being consumed.
Your slam target is 28

 

[crimson avenger]

I see from your poolmath logs that you’re using your swg to maintain your fc - that can be problematic when trying to measure consumption as every cell is different & has different factors to consider like age, salt level, scale etc.
the poolmath app just lists those outputs as a “guide” to help you dial a swg in & figure runtimes under normal conditions.
I suggest u turn the cell off & dose manually w/ liquid chlorine to get a true understanding of fc loss @ this point - it is likely masking your fc loss simply because u have an oversized cell.
C.c.’s are there because the chlorine is being consumed.
Your slam target is 28

Thank you for your answer. The main reason I am still using the generator is because I am working, sometimes long days. So there are gaps in which I can’t be testing so I have to make an educated guess as to how much chlorine loss I have and then calculate a run time for my generator over the course of the next day.

It is a new pool/SWG and my salt level is 3600.
I turned off the salt water generator just now and I’m going to see what happens over the next few hours.

 

[crimson avenger]

Still SLAMing. Think I had some testing errors this morning. Only used 5 mL when testing FC to save reagent. Added 5 ppm bleach. Tested twice and got 38.
Retested 6 hours later with 10 mL and got 26.5. So adding a bit more to keep above 28 as I think my CYA might be 70, not 60.
My ph meter reads 8. My ph meter should not be affected by high FC so I was thinking about adding some muriatic acid to bring it back down to 7.6.

Is that sound?

 

[ajw22]

Do NOT adjust pH during the SLAM Process. Nothing in your FG pool cares about a high pH.

The more you adhere to the SLAM Process the smoother it goes. There is a lot of science behind the steps which should be followed exactly.

 

[crimson avenger]

Do NOT adjust pH during the SLAM Process. Nothing in your FG pool cares about a high pH.

The more you adhere to the SLAM Process the smoother it goes. There is a lot of science behind the steps which should be followed exactly.

Got it! Thank you!

 

[crimson avenger]

Need a little guidance here/have a couple questions.
Yesterday during day was cloudy and I wasn’t really seeing any FC loss, and I was definitely above the FC of 28 for my CYA of 70.
I’m running out of reagent (going to the pool store to get more today) so needed to ration a bit, so only checked three times yesterday.

Well, a major thunderstorm dropped 3.5 inches of water in my pool between yesterday afternoon and this morning. Given how small my pool is and how many steps/benches there are, 3.5 inches of water actually translates into adding about 15% volume.

My FC was 23 last night, so thinking I was below my 28, I added enough chlorine to raise 10 ppm just to have some buffer.

Well this morning my FC is 35, CC is 1.0 - pool is full of leaves (we are waiting for the PB to install the pool cover). Realizing how full the pool was, I re-checked my CYA and it is 60 (which is consistent with a dilution of about 15%). So now we’re back to a target of 24. So I’m waiting and seeing where we get to today.

Seems like I’m losing about 14 ppm FC daily.

I’m frustrated. Our pool is perfectly clear when leaves/debris/bugs aren’t in it.

Our light niches set empty for about 6 weeks before they installed the lights. Am I at the point where I need to take the lights out of the niches and check there? Or just keep SLAMing/brushing/vacuuming? I’m a newbie and not sure I have the tech know how to take the lights out.

 

[ajw22]

Less then a week is a short time for the SLAM Process. The algae took weeks growing in your pool. The chlorine can’t nuke it in a day. It takes patience.

 

[Mdragger88]

Check the lights! & keep slamming, brushing, & vacuuming until u meet all 3 end of slam criteria.
The lights should be a completely sealed unit that just sits in the niche. Turn off their power & maybe have the pb guide u if you’re uncomfortable with it. It’s usually just a couple of screws.
Until then remove the debris that falls as often as possible.
We generally say to leave a cover off for the majority of SLAM Process

 

[crimson avenger]

Check the lights! & keep slamming, brushing, & vacuuming until u meet all 3 end of slam criteria.
The lights should be a completely sealed unit that just sits in the niche. Turn off their power & maybe have the pb guide u if you’re uncomfortable with it. It’s usually just a couple of screws.
Until then remove the debris that falls as often as possible.
We generally say to leave a cover off for the majority of SLAM Process

Maybe I can get the PB to send someone out to show us how to do the lights as you mentioned.
We also haven’t been instructed how to clean the filter. So that hasn’t been done yet either. But our filter is far larger than needed for our pool, and our filter pressures haven’t changed a bit.

 

[kimkats]

I think you need to clean your filter. Look for your owners manual and get ready to get wet LOL

Turn off the pump. Close any valves you have. Take the top off, take the cartridges out. I liked to put mine on a cement block when I had cartridges to keep them off the dirt. I would then make sure my hose nozzle was set on single stream and hose it down good. Aiming the hard stream into the folds of the filter. I also hosed it off inside to make sure I get as much out as I could.

Good luck!

 

[crimson avenger]

Okay, I am getting some pretty varied results when testing my pool water. It seems to vary all over the pool, even though I’m running my pump at 1600 rpm around the clock. So there’s either testing errors or true local variation in the FC level. I’m taking the sample 18” under water. I’m rinsing the cylinder and Speedstir thoroughly.
So I decided to take last night’s last sample and this morning’s first sample from the same locations and the FC level went up! So I’ve been taking multiple samples this morning.

FC/CC levels:
last night:
29.5/1.0
25.5/1.0
this morning:
26.5/0.5
29.0/0.5
27.0/0.5

So the signal required is less than the error of my testing. How would you interpret these results? Good news is my chlorine requirements have dramatically reduced in the past couple of days, only had to add 2 cups of bleach yesterday. Pool is clear this morning - minimal/no “dust.”
I was planning to keep at SLAM level and do another OCLT tonight just to be sure. Is that rational? Suggestions?

 

[Mdragger88]

When doing the Overnight Chlorine Loss Test are u using a 10ml sample? If not do that tonight & in the morning. Also be sure you wait 30 min to an hour after your last addition before testing & be sure your swg is completely off.
If these are all true its likely a testing error - just do one test each time but take your time & :
1) use a 10 ml sample
2) use 2 level scoops of powder
3) let the drops fall from the bottle w/ minimalpressure
4) 1 drop per second

I think you’re on the right track by keeping slam level for 1 more day.
If u don’t wanna have to do this again later you should definitely check the light- you should be able to look it up by brand & see how it’s put together.
Also you’d be surprised how much gunk can accumulate in a filter during slam.