Need hlep with FC

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reidsmith

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Jun 16, 2008
12
I need some help with free chlorine level in my pool. Have been a pool owner for over 20 yrs. and then first time I can't get a reading.
I'm new to these forums so bear with me.

I have all the test results so I will wait for a response to reply to. I'm new here so I'm not sure how to post a question.

Thanks for your patience.
Reid
 
Hi, Reid,

Welcome. Take a look in "pool school" up in the header. Look for the first article, "Please read this before you post". Provide as much of that as you can and we'll all chime in to help.
 
Trouble getting a free Chlorine reading.
Opened poll three weeks ago. Pool is clear.
pH-7.2
Alk-94
FC-0.1
TC-0.4
CH-N/A (vilny)
CYA-50

I have an automatic chlorinator with 3" trichlor pucks.
Chemicals on hand are:
Borax-4 lbs.
CYA- 5 lbs.
Sodium Hypochlorite 12.5%- 6 gallons
Arm and Hammer- 15 lbs.

First time in over ten years that I can't seem to get a FC readings.

Have been adding clorine two gallons at a time every four days and still can't get a good reading.

any suggestions would be appreciated.

Reid
 
Good Morning, Reid,

Thanks for that very thorough post. Your numbers look pretty darn good so your inability to hold FC is a bit of a puzzle.

So, let's get to basics. FC is consumed by only two things.....the sun and organics in your pool. Let's take the sun out of the variables and test to see if organics is the culprit (I suspect)

After the sun is off your pool tonight, put in enough of that liquid chlorine to get your pool to around 6ppm (calculate it pretty carefully) Then test about 45 minutes after you've put it in and record that FC level (hopefully 6ppm). Then tomorrow AM (before the sun hits your pool) test it again. If you've lost more than 1.0 of your FC, the inescapable conclusion is you have something growing in your pool and will need to shock up to about 20ppm (with liquid chlorine) to kill it.

Let us know what you find out.
 
Dave,
The problem I am having is calculating how much liquid 12.5% chlorine to add.
For several years I have kept the automatic chlorinator at 3 and every sunday add 2 gallons of 12.5% liquid.
The FC always stayed at 3.0 unless we had a streak of hot days or bather load. Then I would add two gallons after one of these occured.

Any suggestions as to how many gallons to add to get it to 6 ppm?

Thanks,
Reid
 
Dave,
One more thing I should have mentioned in my first post was the weather around here.
Right now it is rainy and 51 degrees with rain expected on and off for the next two days.

The other thing I will assume is that the filter should run over night after the chlorine is added.

Normal run time is 8 hours a day.

Reid
 
The CYA/Chlorine chart and the Pool calculator are very helpful in calculating proper dosing.

You need a good test kit tho, especially when shocking, so you can measure your FC above 10 and your cc's.

Be careful turning up your feeder, the faster you go through the pucks the more CYA you will have in your pool and you are just about right at 50, so you don't want much more.
 
Used the calulator and just added two gallons of 12.5% chlorine. Will check in an hour and add two more if required.
(nos sun so what can it hurt?)

I'm aware of the CYA with the chlorinator so I've left it where it always is at 3.

One thing that's confusing me is the CC. Mine is at .3 ppm and from what I've read it should be below .5. am I missing something.

One more simple question. For the past 20 years I've done the same routine and have had a perfect looking pool.
Test every day and add chemicals as required.
Add two gallons of 12.5% chlorine evey three weeks or less. Depending on swim load and weather.
Add two pints of algacide (n-alkyl dimethyl benzyl ammonium chlorides 9.96%)(Methyl ammonium chlorides .04%)
(should I be wasting my time with algacide?)

Please bear with me on all the questions. I never considered myself an expert but whatever I have been doing for several years has worked. I've never had to do much more than the above with the exception of TA and CYA when required
but I've also never had a problem with FC being so low.

Hopefully adding an extra dose of chlorine will get me started.

Once agin thanks to all.
Reid
 
.3 cc indicates something in your pool consuming your chlorine. Even tho it's below .5 (time to shock) it still indicates you have an unidentified issue..which explains your inability to keep your FC up.

Shock until the shock level holds overnight, if you lose less than 1ppm and your cc drops to zero you'll be fine. Your water is clear right? That's a good sign.
 

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Yeah, that's frustrating when what you have done stops working. I would explain it away like this.....you have been on the edge" several times without knowing it and this time everything alined to give you a low FC...enouigh to get algae started (Yep, you can't see it at first) Now, you are probably breaking even....enough FC to keep the pool water clear but not enough to completely clear the pool of algae. I think you're right that your big dose of FC (shocking the pool) will tip the scales back in your favor and your FC consumption will return to normal.

A well-chlorinated pool requires no algaecide but some folks like to use it for "insurance"....I don't use it.

CC's below .5ppm are irrelevant and I would disregard them.

There's some pretty good articles up in "Pool School"....review some of those when you get a chance.

My overall view is that you have a good understanding of what's going on with your pool but it seems like you may not have been testing frequently enough and allowed the water to "slip" just over the edge from time to time.

Since you just dosed with FC, tonight would be a good time to check FC just after the sun is off the pool and then again tomorrow AM.....see if there's a drop greater than 1.0ppm.
 
After just over and hour the two gallons of 12.5% ch raised the FC to just under 6.0.

Will check agian later tonight and see how much it drops. No sun today so I'll check in a couple hours.

Thanks to all for the advice. I think I got spoiled and now I have to work at more than I have in the past.

ps.
Some what ifs:
If the FC drops more than 3 ppm before evening would it be wise to add two more gallons of chlorine before I retire for the evening and run all night and check again in the morning?

Reid
 
Well here's the latest:
Put two more gallons in at 4:30PM yesterday. FC was about 3.0

Here's what I have as of 12:30 pm today:

pH- 7.2
Alk-96
FC- 0.3
TC- 0.7
CA- N/A
CYA- 59

Still not having much luck with the FC.

Reid
 
Reid,

Hey. You apparently have a pretty good dose of organics in your pool and really need to shock.....it's gonna take a lot more chlorine than you've been using.

There's an article on shocking up in "pool school" but basically, you need to take your FC up to about 20ppm and hold it there until:

A. You hold FC loss to 1.0 or less overnite
B. Your CC's test .5 or less
C. Your water is sparkling

Then you should be able to go back to your routine.

Almost everyone fails to realize just how much chlorine it takes to keep your shock level up during this process......I'd have fifteen jugs on hand at least.

Just a thought.....do you close your pool in the winter? What was your CYA level at the start of this season?
 
I had a similiar experience for 2 years in a row, and was at the point of filling in my pool with dirt!!! :cry: I finally found someone to give me some expert advice to fix my problem. She ordered a bottle of phosphate remover and had me add it to the pool. Wait 48 hours, then add the chlorine. The water will turn cloudy when you add it, but it clears up in a day or less. It worked.

If you can have your water tested for phosphates, its worth a try, in my opinion only.

I went to several pool places for help, and they had no idea or answers as to why I had a sparkling clear pool, but could not get a FC reading. Luckily someone was able to help.
 
The jury is still out on Phosphates.... I went through PhosFree some time sgo and my filter was screwed up for five days. Owning a pool for 20+ years I should have known better but like an idot I tried it. I even contacted Natural Chemestry and they sent me FREE product to get hooked on it. That's when I decided something might be up. I have a good rapport with my pool guy and he knows I know as much if not more than he does about a pool. He's about 28 and I'm 58. I confronted him about Phosphates and what I went through and he apologized and said it won't work for everyone.

I have NO algae present and right now believe that Algae and Phosphates have something in common. The thing I'm fighting with is FC. I have no algae present what so ever. So Natural Chemistry even acknowledged that I shouldn't go through what I did before and agreed that Phosfree won't necessarily help with the FC but if I had a bad algae problem it might.

Thanks for your reply but I've owned this pool for over 20 years and have never heard of Phosphates until no so I'm real skeptical as to the use in my pool.

Even though I'm a new user on this forum I'm a firm believer of the BBB because that's all I've ever used for over 20 years and so far it has worked.

One other thing I thought I would mention is that a month ago they tested my pool for Phosphate and it was well over 2500 ppm and that it will never dissipate unless it's treated with their product. (another money maker for them) For the heck of it I had them check it today and , magically, it was down to less than 300 ppm. Well within the acceptable level.

Not sure where it went to but It's gone.

I know this is long and your comments are appreciated. I just don't like to add anything to my pool unless it'S bleach, borax and good old arm and hammer.

Reid
 
It is incredibly rare that phosphates make any difference so long as you are maintaining an appropriate FC level. My phosphate level is consistently above 4,000 and I have never have any problems (except when I hired someone to close the pool for the winter).

Removing phosphates is most useful when you are allowing the water to get unsafe. With really low phosphate levels you can recover from unsafe conditions in hours instead of days. I see that as a significant disadvantage, encouraging people to allow unsafe conditions (low FC levels) will lead to swimming in unsafe conditions will lead to trouble.
 
Dave,
I do close the pool in winter.

The CYA was low this year. The first time in years. I added 4 lbs. CYA and it came up to just above 40. It's gone up a little with the tri-chlor tabs since then.

You mentioned 15 gal. of bleach. I have 12.5% chlorine so do you think 8 gal. should be enough?

Reid
 

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