What is the danger of high CYA and attempts to mask the problems associated with it?

I am in a running battle with my pool service person.
He ignores CYA levels and instead tries to treat problems by doing the following:
1. Algeacide
2. Pool Clarifier
3. Reduction of phosphates.
and who knows what else.

On testing with my test kit I get:

CC 0
Ch 276
Cya 140 Confirmed by pool store test
TA 110
Pho 0

The pool shows slight algae buildup in a few shady areas.
The water is not crystal.

I know I have to drain the pool for the second time, after last drain CYA was 20, he added enough to get to 140.
He does not understand.

It seems he is controlling the algae for the most part, but I think that we are not killing bacteria etc. because of the CYA Chlorine ratio.
Am I right? The fact there are no CC's and there is algae makes me think the chlorine is basically ineffective at this level.


Mod Squad
TFP Expert
LifeTime Supporter
Apr 17, 2010
East Texas
Why not remove yourself from this running battle and just "RUN"! The first 3 things you mention you know are not necessary. Is it an option for you to be able to run the pool yourself? Please add a signature line to your profile describing your pool.

We are not about "controlling" algae. We kill it, never let it come back.........and enjoy our pools!@

FC of 4 with a CYA of 140 is ludicrous pool management.


Bronze Supporter
Feb 27, 2016
Danville, CA
Chlorine too low to deal with that CYA. Stay away from the pool store and get a good test kit. Use bleach or liquid chlorine to get the FC up per CYA ratio.

Sent from my SM-G900V using Tapatalk
I have a good test kit. TF100. Unfortunately this is a winter residence so I cannot maintain the pool myself.
We have a summer pool that I maintain myself and have no problems at all. Winter is not problem as the pool maintains itself as the water is constantly being exchanged. That is what 12 feet of rain will do with water temp of 40 degrees.
It was more of a general information question on whether bacteria were being destroyed. My gut feeling is they are not, but I wanted some other input. I will put my equipment in.

Divin Dave

TFP Expert
LifeTime Supporter
Oct 2, 2013
Longview, Texas
You need to get away from your pool guy. Its easy to do it yourself, and for many hundreds of dollars less.

If you know what we know, you wouldnt need all those expensive $ worth of shock, algaecides and all that other stuff.
And your pool would be 100x more sparkly and enjoyable.


Well-known member
Jun 8, 2015
Rocklin Ca
#1 Algaecide: Snake Oil can really mess your pool up to the point you have to drain it.
Clarifier: moderate snake oil you really don't need it
phosphates reduction (Phos-Free) Total SNAKE OIL one thing it will do is reduce the clutter in your wallet.
I would find another pool service


TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
NW Ohio
Have you considered *changing* pool guys? Find one who is more in agreement with how you want your pool cared for.

Yippee :flower:
I'm with Yippee. If this residence is in a warm area with plenty of pools around there should be more options than just that guy. It is going to be difficult to find a service company that adheres to the FC/CYA ratio and actually makes an attempt to avoid algaecides and the like, but you might be able to find someone who will at least work with you on creating a plan more compatible with TFP. If the service is during the times you won't be using it you could ask a service company to only use phosphate reducer (which is NOT "total snake oil", only a typically unnecessary addition) and use unstabilized chlorine to shock. That will be difficult, if a company normally uses trichlor powder to shock you will have trouble convincing them to lug around liquid chlorine or cal-hypo just for your pool, but might be worth speaking with someone.

Bottom line, and to answer the question, bacteria is far less capable to withstand chlorine than algae so it is probably safe even being overstabilized. I would personally want to get things back in range before actually jumping in though.
Thanks for info about bacteria, italics on probably noted, not going in pool until I fix the problems.
Can anyone tell me why the CYA/Cl relationship is different for SWG pools?
And yes, hunt for new pool guy is on!


LifeTime Supporter
TFP Guide
May 14, 2015
Cartersville Ga
Thanks for info about bacteria, italics on probably noted, not going in pool until I fix the problems.
Can anyone tell me why the CYA/Cl relationship is different for SWG pools?
And yes, hunt for new pool guy is on!
It's based on the fact that the SWG produces chlorine over a period of time, whereas manual additions happen all at once. Also, SWGs have a specific life, and the higher CYA means the FC isn't being sacrificed to the sun.


Bronze Supporter
TFP Guide
Jun 26, 2012
Edmond OK
Can anyone tell me why the CYA/Cl relationship is different for SWG pools?

SWGs add chlorine at a slower, steadier rate than pouring in bleach once or twice per day. So you can keep the CYA higher and thus experience less burnoff due to UV rays without worrying about the FC level dropping too much and letting algae get started.


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida

You have a pretty good handle on the chemistry we teach. Even though you can't be there, I think you can find a person to take care of your pool under your remote supervision.

He will need a test kit and will need to be taught how to use it. Results can be reported to you and you can tell him what to do. You'll have a back up of everyone on this forum.

You are currently wasting a LOT of money.