Pool math question

[mknauss]

If you have that quick of FC drop with a CYA of 60 or higher, you have a lot of organics in that water.

 

[jhenson67]

I’ll do the SLAM this weekend so I can maintain the high FC.
Do I need to worry that the high chlorine will etch the fiberglass?

 

[mknauss]

Do I need to worry that the high chlorine will etch the fiberglass?

SLAM level FC is not high chlorine. And no, chlorine has no effect on it.

 

[jhenson67]

I’ll do the SLAM this weekend
Thanks

 

[jhenson67]

I have a question before I get started with SLAM
I did a overnight test and there was no chlorine drop
CC is near zero
The water is clear but there is a sour hot tub smell to the water.
Should I go ahead with SLAM?

 

[mknauss]

You were getting very fast FC drop earlier this week. Now you are not getting any overnight drop in FC.

I would check all your processes. Something does not add up.

 

[jhenson67]

I carefully tested at 8:00 last night
It took 9 drops to turn the 10ml clear= 4.5ppm
Tested again at 6:45 this morning, same
4.5ppm
It rained heavy yesterday so I vacuumed and adjusted the ph, TA and FC 2 hrs before the 8:00 test.

 

[PoolStored]

Just looking through your logs. Looks like your FC is consistently low when you test (1, 2, 2.5, 4) over the last week or so. You likely have something growing. For a CYA level of 70, you should not let FC get below 5. Ever. You should try to keep it up at 8-10 and never let it get below 6 for a margin of safety. If I let my FC get close to minimums it will cloud. You should follow this chart --> FC/CYA Levels

Looks like you added Muriatic to lower your pH. That is great, but any pH in the 7s is just fine.
You noted you added 24oz of Calcium Chloride. However there were no CH test results. What were you trying to do?
You noted you added 24lbs of Baking Soda. Are you sure that is right? That would have raised your TA by 200. I'm assuming you added 24OZ. Your TA at 70 is just fine. I wouldn't adjust your TA any more. Any TA above 50 is fine. 60-80 is recommended.

Generally your numbers look fine. I would ONLY focus on FC at this point and yes, I would slam this weekend. Add some Muriatic to get your pH down to 7.2-7.4 and follow the SLAM process. Print it out and keep it with you! The more times you can test and add Chlorine, particularly in the beginning (like every hour), the faster your SLAM will go. SLAM Process

Good luck! We are here to help!

 

[jhenson67]

Thanks, I didn’t realize I put 24 lb, it was supposed to be oz. I did forget to record a couple of results after adding 24 oz.
Imagine pools says I have to hold there recommendations for the warranty, and those number don’t align with TFP very well.
I will do the SLAM and report the results.
Thanks

 

[PoolStored]

Imagine pools says I have to hold there recommendations for the warranty, and those number don’t align with TFP very well.

What are their recommendations?

 

[jhenson67]

FC 1-2
Ph 7.2-7.4
TA 80-120 with 100 recommendation
CH 80-120
Cya 30-50

I don’t see how I’m going to be able to do this, I need to get my cya to 30
But I was trying to figure that out will pool math last night. Any way I look at it my csi is going to be -.4 or less. This is going to add NO protection to my heater.
I was doing great the first couple of months before the tabs got the cya up to 80

 

[PoolStored]

FC 1-2
Ph 7.3-7.4
TA 80-120 with 100 recommendation
CH 80-120
Cya 30-50

I don’t see how I’m going to be able to do this, I need to get my cya to 30
But I was trying to figure that out will pool math last night. Any way I look at it my csi is going to be -.4 or less. This is going to add NO protection to my heater.
I was doing great the first couple of months before the tabs got the cya up to 80

The pH, TA and CH requirements from your pool manufacturer, while not in line with TFP are just fine. Keep those levels.

Our general recommendations:
pH start with a 7.
TA 60-80. This is to slow pH rise. 100 TA is just fine. (I would shoot for 80, within their requirements and will slow pH rise).
CH 80-100 is just fine, and certainly within recommendations.

Your real issue is going to be FC and CYA. You need to review this chart --> FC/CYA Levels

You cannot maintain a high enough sanitizing HOCl in the pool to keep algae at bay with FC of 1-2ppm at any level of CYA. If you go to 0 CYA, you will consume a large amount of FC on a daily basis and the water will be harsh.

If you want to get your CYA down from 70 to 30, you will need to exchange 60% of your pool water. With a fiberglass pool, you do not want to drain, better to exchange and avoid the pool popping out of the ground . Good read here, includes "No Drain Water Exchange" section:

Draining - Further Reading

www.troublefreepool.com

If it were me, I would exchange 25%-40% of my pool to get CYA down to 40-50. Then I would SLAM. I would then follow the FC/CYA chart and keep my pool (assuming 50 CYA and following the FC/CYA Levels) FC at 6-8 and never let it get below 5. We have 1000s of fiberglass pool owners here that follow this method with ZERO damage to their pools.

Inspiration: How Clear is TFP Clear?

 

[jhenson67]

That’s such a relief to know. I was getting very frustrated because I thought “ I have this!” Then the cya got out of hand due to those pucks the pool store sold me. The FC level started getting very unstable. Then I found TFP.

 

[PoolStored]

the pool store sold me

I. AM. PoolStored!

 

[jhenson67]

Yeah, the said this chlorinator is free and comes with the pool. Free my Rear!

 

[jhenson67]

Lesson learned

 

[PoolStored]

The good news is that you are in the right place. You DO "got this," and we'll help. Once you get through the cycle (drain, slam), maintaining will become second nature, super easy and cost A LOT less. Oh, and you won't fight the Algae ever again if you follow the Chlorine/CYA level recommendations. I printed this out and kept it with my test kit --> FC/CYA Levels

 

[jhenson67]

Thank you

I will be back to a good place for parties soon.

 

[jhenson67]

Ok I’m 7 hrs into the SLAM, bringing the FC back up every 4 hours. The sun has brutal today. The odor is subsiding. I’ll do a overnight test tonight. And hopefully the odor is gone in the morning.
The water is super clear and there’s no sign of algae.

 

[PoolStored]

I would do it every hour or two! Will speed the process.

Can you post pics of your pool?