Ready to fill it with dirt and start a garden

[izjay]

My pool (specs in my signature) is about 2.5 years old. I live in South Florida. I maintained it myself for the first two years and have had crystal clear water the majority of the time. I had a few algae issues a long time ago. One was due to phosphates and the other was due to my ozonator dying. These happened a long time ago and I was able to get them under control easily. I used to run my pump 8 hours a day, during the day, and kept my chlorine generator low (around 25%). During the first 2 years, I hardly ever brushed my pool due to having the robot. I run the robot weekly.

At the end of last year, I had an issue where my robot pool cleaner wasn't working properly and my salt cell was having issues. I did not realize I had an issue due to a solar cover being on my pool. When I finally realized I had a problem, the water was very cloudy (white). Since then, I have tried many times to shock the pool and it seems like it works and then my problems begin again. I have done quite a bit of research on your site regarding testing and shocking.

The water has been clear for a couple of weeks, but I have to add significant amounts (up to a gallon) of chlorine daily to keep the chlorine level above 5 ppm. I even drained half of my pool water about a month ago. I now run my pump 12 hours a day and keep the chlorine generator at 100%. It can't keep up. Sometimes bubbles form on the surface of the pool if you splash the water. I have not used any form of algacide in over a year. I am cleaning my filter cartridge at least weekly.

Here are my current levels (Taylor K-2006 test kit):
FC - 27 (currently shocking, see below)
CC - 0
CYA - 50 (I added approx. 1 pound of stabilizer yesterday after taking this reading)
PH - 7.8
Alk - 110
CH - 120 (this was close to 400 the last time I tested. Maybe the partial refill dropped this?)
Ammonia - 0

I couldn't take it anymore and decided to try shocking the pool again. I decided to try and keep it in the 28-30 ppm range based on the CYA/Chlorine chart. The water has been crystal clear since I started, but the chlorine levels swing all over the place. It will look like it is stabilizing and then it will drop big time. My SWG is off during the time period below.

Here are my FC readings starting on Sunday (SWG turned off):

3/31
3:30 pm - 8 ppm, added 2 gallons chlorine
7:30 pm - 28 ppm, added 1/2 gallon chlorine
10:40 pm - 29 - 30 ppm

4/1
8:00 am - 22 ppm, added 1 large jug ultra bleach
9:50 am - 27 ppm
10:50 am - 27 ppm
12:30 pm - 26 ppm, added 4 cups chlorine
7:30 pm - 19 ppm, added almost full large bottle of ultra bleach
10:20 pm - 25-26 ppm

4/2 (I ran my fountains all day this day and overnight until the next morning)
7:50 am - 24-25 ppm, added 8 cups chlorine
11:00 am - 24 ppm, added 1/2 gallon chlorine
2:10 pm - 28-29 ppm, added approx. 1 pound of CYA
5:00 pm - 21 ppm (this is where I lost it and added 2.5 gallons of chlorine)
6:20 pm - 54-55 ppm
7:20 pm - 54-55 ppm
9:00 pm - 53 ppm

4/3
7:30 am - 35-36 ppm
1:00 pm - 34-35 ppm, added 2 cups acid (I do this every week at the same time)
3:30 pm - 27 ppm (getting ready to add yet more chlorine)

CC was zero during this whole time. I also checked ammonia and it was zero. Is this a normal type of fluctuation while trying to shock? I am going to go through a ton of chlorine at this rate. Keep in mind that my pool is crystal clear with no visible signs of algae. I brush it daily.

One other thing that I will mention is that my pool seems like it is having trouble holding CYA. We are hardly using the pool and it hasn't overflowed in more than 6 months, so it shouldn't be dropping. It just seems to want to stay at or below 50 ppm. I know ammonia can eat up CYA, but I have tested ammonia many times and have not seen a reading above zero. I am also trying a product (past 3 weeks) called AquaFinesse. A friend of mine is in the pool industry and gave me some free to try when he overheard me ******** about my pool problems. I just wanted to make sure I am clear about everything I am using. Oh yeah, I have two filters that I rotate and they are both less than 6 months old.

Sorry for the long post. I am just trying to provide as much information as possible. Any help is greatly appreciated.

 

[jblizzle]

Welcome

Thanks for the details.

First a few notes about the past ... phosphates do not cause algae. If you keep the FC at the appropriate level, algae will not grow regardless of phosphates being in the water. Second, an ozonator has very little use for outdoor pools as the sun will do the same thing, so that also did not likely cause algae growth.

Since you have had to bump up your SWG, that could indicate it reaching the end of its life. Seems like the cells are good for 3-5 years depending on the amount of use they see. You can confirm it is working by testing a water sample right from the pool return to see if the FC level is higher.

It is not uncommon for the FC level to drop while shocking. Since the level is dropping overnight when the sun is not breaking down the FC, there must be something somewhere in the pool using it up. Since you also say your CYA seems to be dropping, I am wondering if there is indeed ammonia requiring the high use of bleach ... unfortunately I have no idea how to confirm this.

It is also not uncommon for the shocking process to take a few weeks ... although that is usually when we are dealing with a swamp and not a clear looking pool. So I suggest keep going at it ... something is using the FC that has to be dealt with.

Hopefully someone else will comment with further ideas.

 

[izjay]

Thanks for your quick reply!

Here are some answers to your questions:
- With the ozonator, it was my understanding that it allows the chlorine levels to be lower. This did seem to be true the first two years. I didn't mean that it caused the algae growth, just that it wasn't doing its job. As a matter of fact, I probably kept the FC too low. But, I always had clear water.
- I forgot to mention that I replaced the SWG cell less than 6 months ago. I tested it recently to make sure it was working. Water coming out of the return (used hose into bucket) was 2 ppm higher than the rest of the pool water. I assume this means it is working.
- I expected drops in FC levels, but is 20 PPM overnight normal for a pool that is clear?
- I tested for ammonia (using aquarium test kit) many times and never get a reading above zero.
- I am fine with sticking with this for a couple of weeks. It just seems to be taking more chlorine than I expected. Maybe I should be using something else to shock?

 

[jblizzle]

My understanding is the ozonator just helps break down the CC (which the sun does as well). You still have to keep the FC level correct.

Good to know the SWG cell should be good.

With a FC level as high as 50+ I think large drops are possible ... although I am no chemist.

I am wondering if there is another way to test for ammonia.

To shock you have to add FC (sometimes a lot of it). Bleach / liquid seems to be the cheapest/safest route ... as it does not add other things to the pool you do not want. Trichlor and Dichlor will add CYA (you know you do not want that too high). Cal-hypo will add CH (you are a little low here, but probably not worth the risk of using it and getting your CH too high).

Just stick to the liquid and keep testing ... so far you seem to be doing a great job of keeping the FC above 24

 

[izjay]

Regarding the ozonator, this is from the manufacture's site for the generator that I have:
Ozone from the pool’s ozone generator acts just like ozone in nature: it oxidizes substances it comes into contact with. This includes a wide range of chemicals and organics that can be oxidized, including bacteria, viruses, algae, oils, human fluids, fungus, chlorine byproducts like chloramines, and some metallic elements. This potent oxidizer combines with contaminants so rapidly that it usually exists in pool water only a very short time, leaving nothing behind but ordinary oxygen (O2).

I am not too concerned about the ozonator though. I may yank it out of the mix if I can get my FC to hold. The problem with an ozonator is that you really can't test if it is working properly and you have to replace the ozone generating cell every couple of years.

 

[jblizzle]

I am certainly no expert on the ozonators ... just basing my comments on what I have read on this forum from the "experts" that are not trying to sell their ozonator systems

 

[zea3]

The problem with ozonators is that they only treat the water when it passes through the ozonator. As soon as the treated water hits the bulk pool water it is re-contaminated. The amount of time it takes to treat the whole pool is equal to the amount of time it takes to run the volume of the pool through the filter system. This generally takes a couple of hours or more. If there is a fecal accident in your pool the kill time from ozone alone would not be rapid enough to stop the bacteria from multiplying. These systems are too small to effectively treat a whole pool full of water at once. This is one of the reasons why we recommend chlorine for sanitation. You can have a safe amount of FC in the water to provide a quick kill time for any bacteria or other contaminants when they enter the pool. There a several discussions on ozone systems and kill times in the Deep End section of TFP if you would like to read more about it.

As for your current issues with the shock process, you may need to pull any lights, removable ladders, handrails, ect to make sure there is no algae lurking in nooks and crannies.

 

[swimcmp]

Out of curiosity what is your current phosphate numbers. I had a customer that the phosphates were over 2500 ppm in a 20x40 with a deep end. The ic40 running 24/7 would not put out enough chlorine to establish a fc or tc reading. Lowered phospate to below 1000 ppm then finally could start to keep up. Just curious.

 

[izjay]

Thanks for everyone's comments. I plan on ditching the ozonator since my SWG should be able to handle the job by itself. I just need to successfully finish this shock process. The only thing I have where algae could be hiding is the main drains, the light, and the pool plumbing. I assume that it is not safe to get in the water with my current levels, so I am not sure what I can do about inspecting them. As for my phosphates, I tested them recently and they were zero.

 

[jblizzle]

It is safe to go on the water up to the shock level for your cya level.

 

[chem geek]

Assuming you are doing the FC and CC tests properly, you don't have an ammonia problem because you aren't measuring any CC. Chlorine and ammonia react very, very quickly to form monochloramine which would measure as CC. You can see what a bacterial conversion of CYA (not ammonia, by the way) into ammonia looks like in this post. Basically, 5 ppm CC would form from 1 ppm ammonia combining with 5 ppm FC (the units of measurement are different between the two, hence the factor of 5). However, it would only last for some hours as chlorine would continue to oxidize it mostly to nitrogen gas (and some nitrate). Also, if you had any leftover ammonia, you wouldn't be holding any FC at all.

So given that you are not measuring ammonia nor CC, I don't think you have an ammonia problem. As for your overnight chlorine loss, it is inconsistent as shown below:

3/31 to 4/1: 29-30 to 22
4/1 to 4/2: 25-26 to 24-25
4/2 to 4/3: 53 to 35-36

Because you really didn't have overnight chlorine loss of significance on 4/1 to 4/2, I wonder if you are doing the test correctly. Are the drops for the FC test well formed and hanging from the dropper or are they smaller and squirting out? If the latter, then you may have static electricity and need to wipe the dropper tip with a clean moist cloth/tissue every so many drops. I'm thinking that you aren't really losing the chlorine as much as you think you are.

 

[jblizzle]

Thanks for the knowledge regarding the ammonia ... I am still learning this stuff as well.

I noticed the inconsistencies with the results as well and in my mind thought that maybe some of the morning tests were after the sun was up. Also thought that something "different " might happen if the FC was extremely high explaining the 20ppm drop.

Good reminder about the testing method.

 

[izjay]

I am fairly sure that I am running the tests correctly. I dilute the pool water by 50% with distilled water and use the 10ml line in the test vile. So, I do not have to divide by 2 for the result. The drops come out slowly and are well formed. I even tested multiple times with multiple water samples when I had the 20 point drop since I was surprised to see this.

One thing I just realized is that I ran my fountains all night long during the period where I had the 20 point drop. I barely have used the fountains over the past year. Is it possible that they had so much bad stuff in them that a bunch of chlorine was used up? The plumbing run from my pump to my fountains is about 30 feet for one and about 60 feet for the other one.

Here is what I am seeing since I last posted chlorine levels
- 4/3 3:30 pm - 27 ppm, 4:30 pm - 8 cups chlorine added, 9:30 pm - 29-30 ppm
- 4/4 7:45 am - 26-27 ppm, also added (after the test) 10 cups of chlorine, getting ready to brush the pool as I do daily while I am shocking

Oh yeah... to answer jblizzle, I do not get direct sunlight in my pool until around noon. At 7:30 am it is still very shaded.

Onward...

 

[chem geek]

One thing I just realized is that I ran my fountains all night long during the period where I had the 20 point drop. I barely have used the fountains over the past year. Is it possible that they had so much bad stuff in them that a bunch of chlorine was used up? The plumbing run from my pump to my fountains is about 30 feet for one and about 60 feet for the other one.

Yup, that could explain it. I know that when I first turn on my solar system for the season, that there is a significant short-term blip in chlorine demand due to whatever was growing in those panels over the winter.

So I'm guessing that with your clear water, near-zero CC, and minimal overnight chlorine drop when you aren't adding additional plumbing paths means that you're in good shape and can move towards the normal chlorine/CYA level by letting the chlorine drop naturally from sunlight during the day and then fire up the SWCG to maintain at least 4 ppm FC with 80 ppm CYA, if that's the CYA level you end up with (that's what is usually recommended for an SWCG so that it doesn't have to work so hard generating chlorine to make up for that lost from sunlight).

 

[izjay]

One thing I just realized is that I ran my fountains all night long during the period where I had the 20 point drop. I barely have used the fountains over the past year. Is it possible that they had so much bad stuff in them that a bunch of chlorine was used up? The plumbing run from my pump to my fountains is about 30 feet for one and about 60 feet for the other one.

Yup, that could explain it. I know that when I first turn on my solar system for the season, that there is a significant short-term blip in chlorine demand due to whatever was growing in those panels over the winter.

So I'm guessing that with your clear water, near-zero CC, and minimal overnight chlorine drop when you aren't adding additional plumbing paths means that you're in good shape and can move towards the normal chlorine/CYA level by letting the chlorine drop naturally from sunlight during the day and then fire up the SWCG to maintain at least 4 ppm FC with 80 ppm CYA, if that's the CYA level you end up with (that's what is usually recommended for an SWCG so that it doesn't have to work so hard generating chlorine to make up for that lost from sunlight).

Did you see that my FC dropped by approx. 3 ppm (29-30 ppm to 26-27 ppm) last night (9:30 pm - 7:45 am)? I was not running the fountains last night. They were only running the night where I had the 20 ppm drop. Shouldn't I keep shocking until I get a 1 ppm drop overnight?

 

[jblizzle]

I think you are right ... if you saw a 3 ppm drop then keep at the shocking levels.

Although this is a good suggestions for people shocking ... make sure you have moved water through all of your plumbing.

 

[izjay]

I think you are right ... if you saw a 3 ppm drop then keep at the shocking levels.

Although this is a good suggestions for people shocking ... make sure you have moved water through all of your plumbing.

Will do. I also just opened up my vacuum line. I hardly use it since I have the robot cleaner. I figure there may be nasties in there too.

Thanks for your help.

 

[izjay]

My chlorine continues to drop by 4 or 5 ppm each night. I then add 12 or more cups of 10% chlorine to get the level back over 30 ppm by the end of the day. The pool continues to be crystal clear. I also removed the light and cleaned behind it. There was a bunch of dusty looking stuff behind the light and the light was partially full of water. I cleaned it completely and replaced the seal. I also took off the main drain covers and cleaned them. I brush every day. But, the pool continues to eat chlorine. Is it possible that some sort of chemical or something ended up in my pool and it is causing this problem? Keep in mind that my pool is only 2 years old and has been mostly trouble free for that time. Should I try shocking at a higher level or with something besides chlorine?

 

[JasonLion]

Keep in mind that ozone consumes some of the chlorine. If the ozone generator is in use the FC level will be lower in the morning, algae or no algae. If you haven't already, try turning off the ozone system for a few days and see what changes.

Assuming that ozone isn't involved, the next step is to try high (mustard algae) shock level and make absolutely sure you are brushing everywhere while at high shock level.

 

[izjay]

The ozone generator is on and I have been running the pump (and ozone) 24 hours a day. I will turn it off now and see if that does the trick. I hope it does before I lose my mind (what is left of it). Thanks for your help.