New Indoor Endless Pool with a 'Sour' smell from the water

Apr 10, 2017
5
Hatfield, MA
#1
Hello all,

First post after reading around the site for awhile. Much more information here then at EP site or their manual.
Started using my indoor EP at the end of Feb after it was installed and have been fighting this sour smell when
I roll back the cover to use it. It seems to come and go, so I have been watching my pool log to see if I can get it to correspond with something I do, but
not really anything consistent. Local pool store advises just to shock it.....

Here are my latest numbers
FC - 3 (coming down from a shocking)
ph - 7.6
TA - 110
CH - 250
CA - 30
I try to keep it around the .5-1 ppm as recommend by EP, but that is very hard to read at that low level. So I put in between 3 -4 oz Bleach (8.25%) daily and adjust accordingly.

Also I seem to be constantly trying to bring the ph back down. Local pool company said that the UV filter will cause the ph to rise, and that
adding ph decrease is just like chasing your tail.. You will never win. He said to leave it where it was ( around 8). ?

Any help greatly appreciated. (I have had 2 outdoor pools over the years and never really had this much trouble with those).
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,094
Franklin, NC
#2
Welcome to TFP!!:handwave:

My first question is what are you using to test your water?

My first recommendation is to stay away from pool stores.

So, following our pool care methods your FC is where we want to see it, in the 3-5 range. As you have found, .5 - 1 FC is almost impossible to maintain and their recommendations do not take CYA into consideration. Plus, we do not "shock" our pools. We maintain the correct amount of FC for the CYA in the water all the time, so no "shocking" is needed.

We generally do not recommend UV, but in your case with an EP that is covered a lot, the UV will actually help. I'll let others jump in, but I see no connection between your rising pH and UV. Your TA is high and the higher the TA the faster pH rises.

How much Pool School have you read? Start with these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool

So, welcome to TFP!!
 
Apr 10, 2017
5
Hatfield, MA
#3
Thanks Tim,

I am using the EP provided Taylor Test Kit K-1005.

I went to the local pool store out of desperation for the odor.
Their advice was to 'shock it'. So if I need to raise the FC levels up to remove the CC, can I do that with just the Liquid Bleach ?

Also their recommended #'s seem to be off from what EP suggests.

[TABLE]
[TR]
[TD="width: 75"][/TD]
[TD="width: 75"][/TD]
[TD="class: xl85, width: 89"][/TD]
[TD="class: xl85, width: 89"][/TD]
[TD="class: xl84, width: 89"]Cl/Br[/TD]
[TD="class: xl84, width: 89"]pH[/TD]
[TD="class: xl84, width: 89"]TA[/TD]
[TD="class: xl84, width: 89"]CH
[/TD]
[TD="class: xl84, width: 89"]CYA[/TD]
[/TR]
[TR]
[TD="class: xl25, width: 328, colspan: 4"]Prefered Levels - From Endless Pools Manual
[/TD]
[TD="class: xl84"].5 - 1 ppm[/TD]
[TD="class: xl84"]7.4 - 7.6[/TD]
[TD="class: xl84"]80 - 120 ppm[/TD]
[TD="class: xl84"]180-250 ppm
[/TD]
[TD="class: xl84"]20-50 ppm[/TD]
[/TR]
[TR]
[TD="class: xl25, width: 328, colspan: 4"]Prefered Levels - From Local Pool Store
[/TD]
[TD="class: xl84"]2 - 4 ppm[/TD]
[TD="class: xl84"]7.2 - 7.8[/TD]
[TD="class: xl84"]100 - 150 ppm[/TD]
[TD="class: xl84"]175 - 350 ppm
[/TD]
[TD="class: xl84"][/TD]
[/TR]
[/TABLE]
I will dive into some light reading as mentioned.


thanks
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,094
Franklin, NC
#4
I am surprised they tell you to keep it at .5 and then provide a DPD (color match) test kit. We would prefer you use a FAS-DPD test kit that has a more definite end point.

As always the recomendations given are different from what we would suggest. Pool School - Recommended Levels

Most of us now keep out TA in the 50 - 60 range to slow down pH rise.

Yes, you can use bleach for everything, but again - we don't shock. Any form of solid chlorine will also add more CYA to the pool.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
9,082
Evans, Georgia
#5
I would venture to say that the cover is containing chloramines (the cooties we are killing with chlorine) and once you take the cover off you are getting a face full of them until they air out. You probably do need more chlorine in the water also.

I would suggest removing the cover a few minutes before you use the swimpool. Test your water.

Maddie :flower:
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
#6
I would venture to say that the cover is containing chloramines (the cooties we are killing with chlorine) and once you take the cover off you are getting a face full of them until they air out. You probably do need more chlorine in the water also.

I would suggest removing the cover a few minutes before you use the swimpool. Test your water.

Maddie :flower:
+1

CC's can smell nasty, but are usually taken care of by sunlight. I'm not familiar with UV systems, but maybe the pool is not getting enough UV exposure?

What is your CC level?

So if I need to raise the FC levels up to remove the CC ............
 
Apr 10, 2017
5
Hatfield, MA
#7
My CC is now zero as I have just SLAMMED it to about 5 ppm with chlorine.

I have just watched the EP sites video on pool maintenance and they say .5 ppm to 1 ppm is all this pool needs.

I am finding it hard to get an accurate measurement at that low of a FC level. Wiil look into the FAS-DPD test kit as suggested above.
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,287
NW Ohio
#8
You did not SLAM your pool. SLAM is an acronym for Shock Level And Maintain. All you did was raise your FC level up a bit.

It is up to you whether you want to follow EP's guidelines or TFP's. They are not going to match. I will say though, TFP guidelines didn't give you 'sour' smelling water...
 
Apr 10, 2017
5
Hatfield, MA
#10
Hello all,

First. I guess I misunderstood SLAMing, so yes I SHOCKED my pool, which I now know is not the standard for this forum.
I was just trying to get my FC levels up high enough to burn off the combined chlorine (if any) and hoping that was the smell.

It was not intention to imply that TFP created the sour smell. I can into this trying to figure out what was causing that smell and correct it.

Seeing that the pool is new I attempt to follow the EP guidelines, which for an indoor covered pool
is to use Cholrox 8.25% bleach about 2-3 oz per day after each swimmer, using a Nature 2 cartridge and a UV inline filter.
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,094
Franklin, NC
#11
Hello all,

First. I guess I misunderstood SLAMing, so yes I SHOCKED my pool, which I now know is not the standard for this forum.
I was just trying to get my FC levels up high enough to burn off the combined chlorine (if any) and hoping that was the smell.

It was not intention to imply that TFP created the sour smell. I can into this trying to figure out what was causing that smell and correct it.

Seeing that the pool is new I attempt to follow the EP guidelines, which for an indoor covered pool
is to use Cholrox 8.25% bleach about 2-3 oz per day after each swimmer, using a Nature 2 cartridge and a UV inline filter.
No worries, we just want your EP smelling sweet so yo can enjoy it.

The idea of "shocking" to eliminate CC is what the pool industry calls "Breakpoint Chlorination" and it is still taught in "Certified Pool Operator" (CPO) classes. We have many issues with the teaching, but heck - the world says they are the "authority". You can read the thread here: Certified Pool Operator (CPO) training -- What is not taught

Now, I cut out the section regarding Breakpoint Chlorination so you could read it and what is taught.

This thread will discuss some of the topics that are either not taught or are taught with incorrect or incomplete information, at least as far as I can tell from those who have had CPO training.

Breakpoint Chlorination
The 10x rule for breakpoint chlorination is wrong and only now some industry people are starting to address this as described here and here, though they are still only accounting for the mistake of not considering that combined chlorine already used up a chlorine atom in combining with ammonia and they are not yet considering that there is still a factor of 5 error in their approach since the units used to derive the 10x rule come from chlorine (measured in ppm Cl2) oxidation of ammonia (measured in ppm N) whereas combined chlorine is measured in the same units as chlorine (i.e. ppm Cl2) where the Cl2 units are 5 times higher than the N units (that's the molecular weight ratio between the two). The oxidation of a combined chlorine that is monochlorourea (i.e. chlorine combined with urea) may require 3x, but that still far from 10x. There also isn't any getting "stuck" -- one can just add more chlorine. When one has persistent CC, it is not due to getting "stuck" but from compounds that do not oxidize as quickly. More technical details about this are described in this post.

The handbook has a newer breakpoint chlorination rule, but it is still a "10x" rule, though uses a target FC as 10x of the CC rather than using an incrementally added 10x amount. It incorrectly states that adding less than the breakpoint calculated amount may not achieve breakpoint, not recognizing that the 10x rule is wrong when starting with CC (it's correct when starting with ammonia measured in ppm N units).

Richard
You need to have the CC level to calculate the FC target for the Breakpoint Chlorination. If you CC was 2 then your "breakpoint" should be 20 following their guidelines. But again, they do not account for the CYA in the water.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
9,082
Evans, Georgia
#12
I think you need to occasionally leave the cover open on the pool now and then to allow it to "breath" some. I have to do this with my outside pool's autocover also. That plus the addition of a bit more chlorine should help things nicely.

Please let us know if this helps?

Maddie :flower:
 
Apr 10, 2017
5
Hatfield, MA
#13
Thanks all four your help. I will take a read on the CPO and Breakpoint, though it seems a little over my simple head !

Since starting to use it in late Feb. we have had it open about 2 hrs a day. However with New England weather, the room gets very humid very fast even running a Broan hi output vent fan. Trying to leave the cover open as the weather has now allowed that. Nice and windy today here in MASS.