New pool, very high chlorine

[Nowhere]

Hi everyone,
We have a new small pool and are a little puzzled by the results we've been getting. Everything was fine until we started up the SWG. We are working with someone and after about a month of the SWG running, he mentioned that there was no chlorine in the pool and so he added chlorine (in addition to the salt, which was 3000-3300 ppm). We went in the pool and there was a very strong smell of chlorine, suits got bleached, hair and skin were dry for days so we knew something was off and got the Taylor K-2006 to test for ourselves. Results were 40-50 ppm FC.
Since then, we've added sodium thiosulfate to no avail, until we shut off the SWG. Once we shut off the SWG, the FC has been coming down with each administration of sodium thiosulfate, though nowhere near as much as it should be coming down according to the instructions for the thio dosing. We've probably added at least 30 tbsp of thio. We've also been consistently getting zero combined chlorine?
Are there any other measurements we should be taking that could help explain why the FC is proving so hard to reduce? and are we correct in assuming that it is in fact the high FC that caused all of those bleach-like effects when we went in the pool? Thanks!

 

[mknauss]

Welcome to the forum!
What is your CYA level?
You really should not need to add anything to drop the FC level. Just letting the sun hit the pool surface should drop it rapidly when the FC is well above target range. FC/CYA Levels
I suggest you read ABC's of Pool Water Chemistry.

 

[duraleigh]

Welcome to the forum

Yeah, you should have to do nothing to lower FC dramatically (perhaps like 30-50% daily) unless you are somehow adding it back in.

ABC's of Pool Water Chemistry as suggested above should get you on the right track.

 

[JamesW]

If you have regular 3% hydrogen peroxide, you can add some to lower the chlorine. Every quart will reduce the FC by about 3.4 ppm.

You might need about 10 quarts, which might not be easy to get.

 

[Nowhere]

Thanks! That was very helpful. We are now at 7 ppm FC, corrected the alkalinity with baking soda, and now just need to correct the acidity (soda ash) and add CYA. Hoping we'll be able to get the SWG working but it seems like that was the culprit in getting us to superchlorination levels. From what I could tell, it shouldn't be an issue that our pool is small because the SWG simply processes the salt ppm in the water, but it almost seems like it can't keep the generation low enough for our size pool.

 

[DanF]

From what I could tell, it shouldn't be an issue that our pool is small because the SWG simply processes the salt ppm in the water, but it almost seems like it can't keep the generation low enough for our size pool.

If you post the details of your pool equipment (pool size/composition, SWG make/model, cleaning system, etc) in your signature, I am sure someone familiar with your system will guide you.

 

[JamesW]

Did you use the hydrogen peroxide?

The pool is very small and can easily get overdosed.

What SWG do you have?

 

[Dirk]

Some SWGs have finer controls than others. Mine can do 1% increments, 1 to 100%. But even if yours can't, you can control the amount of chlorine it puts into your pool by altering its runtime. Most folks new to pools overdo their filter pump's runtime (that's a different topic altogether), but you can probably do with less. So decrease your SWG setting to its lowest. If that is still too much chlorine, then decrease your pump's runtime. Eventually you'll find the combo of SWG setting and pump runtime that works in your pool. If your pool looks clear and no extra leaves on the bottom or surface, then you have enough pump runtime. That's the gist.

Once you give us more details about your equipment, the experts here will get you fine-tuned and walk you through the setup if you need help.

 

[Nowhere]

I think this is what we have:
Hayward AquaRite 900 SWG
Crystal Water 570-0425 filter
Jandy PSB220 air blower
Pentair pump - can't find model info, but 3.0 hp/ 3.95 sfhp
Sta-Rite Max-E-Therm 400 heater
We estimate the entire pool at about 4500 gallons, of which approximately 1/6 or so is a hot tub. We hardly ever run the heater because the pool warms up sufficiently with the sun. The cover is always on, except when we're using the pool. Currently the filter pump is scheduled to run 7 hours/day. Depending on the weather, if it's typical summer weather here, we would use the pool a few times a week, 1-2 hours each time.
Appreciate your expertise!

 

[Dirk]

OK, now we're gettin' somewhere Nowhere!

I don't know the AquaRite, but many here will. While you're waiting for one to happen by, please slip all the equipment info you found into your signature. Something along the lines of how I did mine would make finding all that info super easy for our busy experts (who might be napping after this long weekend). Do you have any kind of automation controller, or do you control your pump and SWG via the control panels on each of those components?

If you can't find the model number of your pump, a picture of it, and maybe another of your entire equipment pad will help. And can you narrow down your location? If you don't want to include your city, pick one nearby or give us an idea of what part of CA you're in. Where the pool is can really affect its chemistry, and so the advice you'll receive. Thx!

 

[JamesW]

With such a small pool and a cover, you're going to have to be really careful not to overchlorinate.

Keep the SWG on the lowest setting and maybe a timer until you get it dialed in.

 

[mknauss]

Check the Aquarite. The cell itself. It should show 940 or 925. Or a T9 or T15.

The pump is an Intelliflo VS if that hp.

 

[Nowhere]

It's an AquaRite 940 and we use the iAquaLink app to manage everything except for the SWG - that isn't connected. (..can it be?) We're in the SF Bay Area. Not much rain, not coastal, and usually in the 70s-80s in the summer.
When the SWG was on, we did notice cloudy water from the filter into the pool and, on the surface, something that looked like an oily slick - is that normal?
Updated my signature with everything so far- thanks!

 

[Dirk]

Nice. Thanks for that. Now the guys can have at it.