How bad are these numbers?

[frustratedpoolmom]

See I'm not real experienced with SWG and their actual operations since I've never seen one. I only know what I know from what I've read on here. I'd say turn it up, it wasn't keeping up - either from low CYA or organics in the water. Since you don't have access to liquid, I'd say set it to the percentage/runtime pretty high and see where you are in the morning, then turn it down if you need to.

 

[jonmar]

So I opted to switch on the Super Chlorinate just this once. I will make sure I have some liquid on hand in the future. Never shocked a pool before, so how do you get the CL back to normal levels? When can you swim again?

 

[frustratedpoolmom]

You turn it off, and the FC will drop, esp if the pool isn't covered. Many users swim up to and at shock level.

 

[jonmar]

I'm going to turn it off in the morning. Thanks for the help.

 

[JasonLion]

If the FC level fell to 0 with a SWG, you really want to shock with bleach, or some other additional chlorine source. You should shock because FC shouldn't ever fall to zero, unless something has gone wrong, like getting algae. With a SWG you can actually have algae even when the water is clear. The algae and the SWG fight with each other. The SWG keeps the algae from ever really getting going but it can't usually kill the algae completely.

When shocking you want the FC level to come up to shock level very quickly. The SWG is designed to raise FC slowly. Adding bleach to get to shock level is much more efficient and more likely to work.

 

[jonmar]

I only read this now and had my SWG on all night at Super. I turned it off this morning and it is at 20%. The CL level was 3 ppm. Do you not think it's possible the CL dropped so low due to my CYA being only 10 ppm, with the pool being in the sun from 11 a.m. till about 8 p.m., or do you think algae is the most likely culprit?

 

[Brad S]

The algae and the SWG fight with each other. The SWG keeps the algae from ever really getting going but it can't usually kill the algae completely.
.

Maybe a high (i.e. 80 ppm) CYA even with a SWG should be re-thought? High CYA levels may not allow the FC to work as efficiently as it could at lower levels? Just a thought mind you

Do you not think it's possible the CL dropped so low due to my CYA being only 10 ppm, with the pool being in the sun from 11 a.m. till about 8 p.m., or do you think algae is the most likely culprit?

Probably. Depends on how high your SWG was set during that time frame. From what i can read here, 10ppm CYA is like not having any? I keep mine around 50 ppm and have no problems. A lot depends on generator capacity, gallons of water in the pool, pump run time, etc.

Or it could be algea. You could do an overnight chlorine test and see if it holds before you decide to shock. If it holds, i'd say its low CYA and boost that up.

 

[jonmar]

Put in about 3 lbs of CYA yesterday and the SWG was going at 15%. CYA has all dissolved. Turned on Super Chlorinate last night before bed and then off this morning with the setting turned up now to 20%. CL levels were 3.0 this morning. Our water is crystal clear. Can some algae exist without any visual signs?

 

[PaulR]

Maybe a high (i.e. 80 ppm) CYA even with a SWG should be re-thought? High CYA levels may not allow the FC to work as efficiently as it could at lower levels? Just a thought mind you

It's not really about FC efficiency. Higher CYA makes it harder to solve a problem. If you can avoid the problems then a high CYA is not inherently harder to work with; but without an SWG it's easier to have problems.

The point of an SWG is to provide a more-or-less constant trickle of new chlorine. As long as the SWG is set to maintain an adequate FC, the exact CYA level should not be an issue. In a clean pool, the necessary trickle is smaller with higher CYA, therefore a higher CYA will extend the cell life somewhat.

After you figure out where to keep the SWG for a high CYA, problems should become very rare, because you're not going to have FC drop to the point where algae can take hold. The only real issue is getting to that point without getting into trouble.
--paulr

 

[PaulR]

Can some algae exist without any visual signs?

yes. The real proof is an overnight FC loss test with the SWG off. See the Pool School article for more on this.
--paulr

 

[Brad S]

Edited to avoid hi=jack of thread.

 

[JasonLion]

Do you not think it's possible the CL dropped so low due to my CYA being only 10 ppm

Sorry I didn't see that. Yes, if your CYA is only 10, then that is your problem. CYA should be around 70 to 80 with a SWG. When CYA is only 10 you will lose most of your chlorine to sunlight each day and will need to run the SWG way more that you would otherwise (which will shorten the cell life).

 

[jonmar]

Had my blanket off all day today as a tester in the hot sun. It was 30 celcius (around 84) all day and sunny. CL has held at about 3 according to the 'cheapo films presents' test kit I have. It was the same one that reported 0 the other day. In any case it would appear the CYA I added on Sunday is working. I have been aerating each evening with my jets and adding PH down each evening as well (about 2lbs), so hopefully my TA will have dropped. I will bring in a sample on Saturday and report the new numbers then. Problem though:
With the aeration, the jets pointed upward create a relaxing rivery flow sound which my wife loves. Will this not constantly increase my PH? Will I be doomed to adding a bucket of PH down every week if she insists on this new found ambiance?

 

[JasonLion]

As your TA level comes down the rate of PH increase will come down. When the TA level gets low enough, the PH will increase far more slowly. So it should be possible to leave things that way if you really want. However, long term, you should point at least one return down to promote proper mixing of the water.

 

[jonmar]

Re: How bad are these numbers? Update

Had the water tested yesterday and came out with these numbers:

CL 3.0
FC 3.0
PH 7.3
CYA 45
TA 170
Adjusted TA 157 (not sure what this is)
CH 200
Alkalai demand- 3 drops.

Our Saturation index is 0.00.
They advised the water was perfect. Isn't the CYA a little low still and the TA a little high>

 

[frustratedpoolmom]

They don't know perfect.

TFP knows perfect.

You need your own test kit! Did you order a K2006 yet?

Ignore adjusted TA for now.

I think you would be better off lowering the TA using Muratic Acid, instead of the PH down. Or did you already have it, that why you are using it? It costs more than MA and adds sulphates to the water.

 

[JasonLion]

With a SWG, I would raise CYA to between 70 and 80.

 

[jonmar]

I already had a bunch of PH down. Where do you buy muriatic acid? What department is it usually found in?

 

[PaulR]

Start in the paint dept, that's the usual place for MA.
--paulr