New-to-me pool... >100ppm CYA / 25ppm Free Chlorine... safe to swim?

Fredfunk

New member
Dec 30, 2020
4
Cocoa Beach, Fl
Pool Size
7500
Surface
Plaster
Chlorine
Liquid Chlorine
Hey, thanks so much for the great website! I just bought a house with a small in-ground screened-in pool, and I'm an absolute newbie. I estimate the pool to be around 7500 Gal (12' x 20' with an depth sloping from 3' to 5'6"). It was a bit dirty when we moved in, so I bought a new vacuum and skimmer bucket and it cleaned up great in just a couple of days. The water looks really good now, at least to my untrained eye. I also picked up a couple different test kits (strips and drops) from Home Depot, but my Cholrine readings were off the charts on both. Based on reading this website, I just picked up the Taylor 2006C test kit, which told me that my free chlorine was at 25ppm and my combined chlorine was at 1ppm. Also, my CYA was over 100ppm. PH and Alks both were in spec (7.4 and 60ppm). The water doesnt smell like chlorine, and after a bit more reading I suspect that this is because the CYA is so high, it is locking up most (90%?) of the chlorine. Is this true? Is it safe to swim? Should I start trying to lower the CYA? Also, how do I regulate the chlorine levels? I have a rainbow feeder that accepts 3" tablets and a small valve that appears to adjust flow. Do I regulate the amount of chlorine in the feeder or just the water flow and amount of time the pump is on? So many questions, but the biggest one is: can I swim yet?!
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,627
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Yes, your water is probably OK to swim in. But since we don't actually know your CYA level, I gotta say "probably."

First step is to try and get a better ballpark CYA number. You can modify the CYA test to get closer than "over 100." Here are some CYA testing instructions, focus on #8. Then report back:

 
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Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,627
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
When you smell chlorine at a pool, you're not actually smelling chlorine. You're smelling the byproduct of chlorine destroying nasties in the water. So when you "smell chlorine," that is an indicator that yes, there is chlorine, but yes, there is something nasty in the water. So not "smelling chlorine" when you know chlorine is in the water is a good thing (it generally means there are no nasties present). So the smell or lack of is not directly related to the CYA or your "lock up" theory.

Yes, you're likely going to need to reduce your CYA. The only way to do that is to exchange water. But we need to get that ballpark figure first to determine how much water to exchange.

Regarding "regulating chlorine levels:" The reason your CYA is off the chart is because of the use of those 3" tabs. That is not a sustainable model for pool water maintenance, despite the fact that it is one of the most common methods used. The use of tabs always leads to an excess accumulation of CYA, which then necessitates a water exchange. That's what a lot of people do. Sound familiar? The better way to maintain a proper level of chlorine (and sanitation) is to establish the proper CYA level, and then use liquid chlorine. You would discontinue using tabs altogether. The alternative method to maintain chlorine is to convert your pool to saltwater and install a saltwater chlorine generator (SWCG or SWG for short). That's what a lot of us here do, because we don't like adding chlorine every few days, nor buying and lugging it from the store. An SWG has a high initial startup cost, and then wears out eventually (years later) but we've figure it out here many times that the total cost equates to the cost of liquid chlorine use over the same time period. For most of us with SWGs, we would NEVER go back to manual dosing. So that's something for you to consider. Either way, you're going to have to give up the tabs, or you'll need to exchange water regularly.

Did I hit all the questions?

Good job on getting the 2006C! And welcome to TFP! Glad you found us. If you stick around and learn the "TFP Way" you'll be your own pool's expert in no time. You're off to a great start.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,627
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Oh, the cheapie Home Depot test kit can probably suffice for some quick water tests, especially if you get your CYA back down, which should bring your chlorine level to something that kit can actually measure. Test strips, I'm sorry to tell you, are complete junk and can't be trusted for anything. Take them back for a refund, or throw them away. They have no purpose in pool water maintenance if you want to do a good job of it. If you can take both kits back for a refund, do that. All you need is the 2006C.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,627
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Take a few minutes and fill out your signature. Something like mine is especially helpful for the folks that will be helping you. Include brands and models as much as possible. Include your test kit.


Your next purchase should be a Taylor SpeedStir. It will seem like an unnecessary expense. Trust me. It isn't, and you'll thank me after the first time you use it. We all have one.


OR

 

Fredfunk

New member
Dec 30, 2020
4
Cocoa Beach, Fl
Pool Size
7500
Surface
Plaster
Chlorine
Liquid Chlorine
Thanks Dirk! I ran the diluted test and CYA was @ ~105ppm (barely past the 50ppm line when diluted 1:2). The chlorine this morning held steady at 25ppm, so no overnight loss. Also, the combined chlorine is zero! Anyway, thanks so much for your prompt response. Also, do you think it is safe to swim, or should I wait for FC to come down to 13ppm?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
43,676
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Welcome to the forum!
You can safely swim in a pool as long as the FC is above the minimum and at or below SLAM level based on your CYA. You must also be able to see the bottom of the pool in the deep end of the pool.
With your CYA of 110 ppm, your SLAM level FC is 40 ppm. It is safe to swim in the pool.
I suggest you read ABC's of Pool Water Chemistry.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,627
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
If you post a full set of test results for your pool, like this:
FC:
CC:
pH:
TA:
CH:
CYA:

and then test your fill water and post these:
TA:
CH:

we can help you calculate how much water to exchange to balance your pool. It's probably going to be at least 50%...

You also need to fill in your signature, so we know what we're dealing with in terms of pool and equipment, please.
 

Fredfunk

New member
Dec 30, 2020
4
Cocoa Beach, Fl
Pool Size
7500
Surface
Plaster
Chlorine
Liquid Chlorine
Thanks everyone for all your help! We had a great time in the pool yesterday, although I could tell that the chlorine was pretty strong once we got out. Here are the full spectrum of tests on our pool water... haven't tested the tap yet but I will soon (lots of boxes left to unpack from the move).

Pool Water:
FC: 26 ppm
CC: 0.5 ppm
pH: 7.4
TA: 70 ppm
CH: 250 ppm
CYA: 105 ppm
 

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Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,627
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Remove the tabs from the feeder and stop using it (like, forever). Your FC will drift down on its own. Other than your CYA, your numbers look good, though you haven't told us yet what kind of pool you have, which matters. Is it plaster/gunite? You will be manually adding liquid chlorine from now on, so keep monitoring your FC level. Once it gets to the low end of your target range (based on our FC/CYA chart), you'll start adding liquid chlorine, dosing an amount based on Pool Math.

Once you provide the fill water spec's and your signature, we can go from there. In the meantime, stock up on some liquid chlorine.

Thank you for listing your test results the way you did. It's how we like to see 'em, and makes helping you that much easier. Looks like you've got testing down. It looks like your smile-ometer is working correctly, too. ;) Nice.
 
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