Undersized IC40? Phosphate Demand? Your advice would greatly help....

iannecj

Member
Jul 18, 2019
9
Central Florida
I have a new fancy pool but I have to add liquid chlorine each week. Been active for 3 months but pool builder had maintained previously. I want to understand my system and do it myself, Picture is attached and signature should have equipment details.

Here's my story....

(1.) When I first took it over pool supply store said 0FC but pool was sparkling clear and seemingly perfect. I start adding liquid chlorine to get 3-5ppm. Saly is 3400
(2.) Pool installer says phosphates must be high given no screen and lots of landscaping around but they did not measure. Also they are looking at the fact that the IC40 is running 12 hrs at 80% and believe its ample for the pool for some reason.
(3.) Pool supply store says they read 200ppb or less phosphates.
(4.) pool installer says thats impossible, adds phosphate remover at dosage recommended for high phosphate and instructs me to clean all filters then shock with (4) 1b bags of dichlor.
(5.) I do that and when I try to read FCL with my cheap $20 test kit cant discren so I order K2006C and phosphate kit from taylor.
(6.) Kit comes 2 days after I add the shock and I am able to check everything...FCL 10ppm, CC0ppm, PH 7.6, Totalk 90, CYA 100 Phosphate might be 0 but there is a slight blue tinge...I would say less than 50ppb for sure.
(7.) I turn IC40 to 0% at 8pm 2 nights ago and run pump with salt off and next morning FC still 10ppm.
(8.) Leaving IC40 OFF I run it half of the day and check FCL and its now at 8.6ppm.

Questions....

The cell seemed to not keep up when I took pool care over I had to supplement. My plan is turn cell of tomorrow and measure a few times until it gets to 6-7ppm and see if I reactivate at normal schedule I can get it to hold. However by my math the cell should resupplying 2.25ppm a day (assuming flow doesnt matter) and that might be too little.
-Is it undersized?
-What is best way to know?
-Flow on my VSF matter so long as its above 30gpm?


The VSF is running at 2500RPM for 12 hrs and cell is at 80%




111689
 

mknauss

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May 3, 2014
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Welcome to the forum!
Great job on getting a quality test kit.
100 is the limit of the CYA test, so you have to do a diluted test. Mix 50% pool water with 50% tap water. Use this mixed sample as your test water. Multiply the result by 2 for your CYA level.
Be sure to follow the SWCG section in FC/CYA Chart

Your IC40 is undersized, but if run enough, should make enough chlorine to keep your FC stable.
In your pool the IC40 can add 5.6ppm FC each 24 hour period if run at 100% for the entire 24 hours. In your climate, you will lose about 4 ppm FC per day during summer. So you need to run your pump 17 hours per day with the SWCG at 100% to add 4 ppm FC.

The rate needed to close the flow switch on your IC40 is not set in stone. It may be far less than the 30 gpm you are using. I run my VS pump at 1500 rpm to close the flow switch on my IC40. We recommend running the pump in VS mode, not VF mode.
Do you have an automation system? Can you add that to your signature?
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
 

mguzzy

Well-known member
Jul 8, 2015
662
OV, CA
WOW cool pool. Does all the aeration from those water features make keeping the pH difficult? I'm curious if there is a way you can run your pumps without the spillovers going. And what are the depths of the main pool and the lower basin. sorry for not answering your question.. and asking so many of my own! Anyway reminds me of Aqua Azul in Mexico.. if I had all the money in the world to make a pool it would look something like a cross between Aqua Azul and Pamukkale
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
8,988
Northern NJ
Welcome to TFP.

To be clear, you are not running your SWG long enough at a high enough % for your pool. Marty gave you the numbers above.

Do you use PoolMath? It does the calculations for you.
 

duraleigh

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As you work on your issues, ignore phosphates. They are simply not relevant. Please read "The "ABC's of Pool Water Chemistry" up in Pool School.

Your basic issue seems to be to reduce CYA first but get phosphates off your plate and your balancing and pool water management will go smoother.

Is your water currently clear?
 

iannecj

Member
Jul 18, 2019
9
Central Florida
Welcome to the forum!
Great job on getting a quality test kit.
100 is the limit of the CYA test, so you have to do a diluted test. Mix 50% pool water with 50% tap water. Use this mixed sample as your test water. Multiply the result by 2 for your CYA level.
Be sure to follow the SWCG section in FC/CYA Chart

Your IC40 is undersized, but if run enough, should make enough chlorine to keep your FC stable.
In your pool the IC40 can add 5.6ppm FC each 24 hour period if run at 100% for the entire 24 hours. In your climate, you will lose about 4 ppm FC per day during summer. So you need to run your pump 17 hours per day with the SWCG at 100% to add 4 ppm FC.

The rate needed to close the flow switch on your IC40 is not set in stone. It may be far less than the 30 gpm you are using. I run my VS pump at 1500 rpm to close the flow switch on my IC40. We recommend running the pump in VS mode, not VF mode.
Do you have an automation system? Can you add that to your signature?
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
Marty!!! Thank you very much. I have an Intellitouch I9 will try to get it added to signature...I am character limited. I will redo CYA and report. I dont want to run for 17hrs so my thought is I am going to argue this with builder and try for swap to IC60. Anything you think I should consider in this regard? Thanks again!
 

iannecj

Member
Jul 18, 2019
9
Central Florida
Marty!!! Thank you very much. I have an Intellitouch I9 will try to get it added to signature...I am character limited. I will redo CYA and report. I dont want to run for 17hrs so my thought is I am going to argue this with builder and try for swap to IC60. Anything you think I should consider in this regard? Thanks again!
Oh and why control to speed vs control to fixed flow?
 

iannecj

Member
Jul 18, 2019
9
Central Florida
WOW cool pool. Does all the aeration from those water features make keeping the pH difficult? I'm curious if there is a way you can run your pumps without the spillovers going. And what are the depths of the main pool and the lower basin. sorry for not answering your question.. and asking so many of my own! Anyway reminds me of Aqua Azul in Mexico.. if I had all the money in the world to make a pool it would look something like a cross between Aqua Azul and Pamukkale
Yes....I can not run rain descents but I still need a little flow over wall to get chorline to lower basin. Even still PH high. Each week an acid gallon and it hasnt been enought yet.

My next worry is total alk is now good but PH is getting high. Not sure how to address. Any idea?
 

iannecj

Member
Jul 18, 2019
9
Central Florida
WOW cool pool. Does all the aeration from those water features make keeping the pH difficult? I'm curious if there is a way you can run your pumps without the spillovers going. And what are the depths of the main pool and the lower basin. sorry for not answering your question.. and asking so many of my own! Anyway reminds me of Aqua Azul in Mexico.. if I had all the money in the world to make a pool it would look something like a cross between Aqua Azul and Pamukkale
Also 7ft main, 4 ft shallow
 

mknauss

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May 3, 2014
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Laughlin, NV
Oh and why control to speed vs control to fixed flow?
The fixed flow right now has you running the pump much faster than needed. It also will hide a dirty filter as the rpm will continue to increase to meet the flow. Much better off to run on VS or rpm standards only.
 

mguzzy

Well-known member
Jul 8, 2015
662
OV, CA
Yes....I can not run rain descents but I still need a little flow over wall to get chorline to lower basin. Even still PH high. Each week an acid gallon and it hasnt been enought yet.

My next worry is total alk is now good but PH is getting high. Not sure how to address. Any idea?
As I understand it if your pH is increased through aeration you don't need to worry about alkalinity as its a physical process not chemical... And I think you loose some FC in that process as well. The pool Chem Gurus here will confirm that. If that is the case then that is another reason to upsize your salt cell. Generally you go twice the rated pool size and you have an IC40 for 40K gal pools and your pool is 30K. That puts it in the IC60 range.
Given that you have such a large lower basin I was curious if they plumbed things in a way that would allow you to recirculate water without having to use the spillover to reduce the aeration effect. But if there are no returns in the lower basin that answers that question. Wouldn't be the first time that a PB isn't thinking about pool chem during construction. ;)
I'm still blown away by your layout. I've spent time at various natural water cascades around the world.. and this just brings back some nice memories. Did you have something like that in mind when you designed this?:D
 
Last edited:

iannecj

Member
Jul 18, 2019
9
Central Florida
OTE="duraleigh, post: 1674443, member: 69"]
As you work on your issues, ignore phosphates. They are simply not relevant. Please read "The "ABC's of Pool Water Chemistry" up in Pool School.

Your basic issue seems to be to reduce CYA first but get phosphates off your plate and your balancing and pool water management will go smoother.

Is your water currently clear?
[/QUOTE]
Thanks yes crystal clear. I'll read basics and take your advice and not worry on phosphates for now.
 

iannecj

Member
Jul 18, 2019
9
Central Florida
As I understand it if your pH is increased through aeration you don't need to worry about alkalinity as its a physical process not chemical... And I think you loose some FC in that process as well. The pool Chem Gurus here will confirm that. If that is the case then that is another reason to upsize your salt cell. Generally you go twice the rated pool size and you have an IC40 for 40K gal pools and your pool is 30K. That puts it in the IC60 range.
Given that you have such a large lower basin I was curious if they plumbed things in a way that would allow you to recirculate water without having to use the spillover to reduce the aeration effect. But if there are no returns in the lower basin that answers that question. Wouldn't be the first time that a PB isn't thinking about pool chem during construction. ;)
I'm still blown away by your layout. I've spent time at various natural water cascades around the world.. and this just brings back some nice memories. Did you have something like that in mind when you designed this?:D
Yes that was some of the idea...the other is I see hegative edge pools but the pretty waterfall part is hidden...seemed better to reverse and I have adult kids and 5 year old kids so 2 depths good too.
 

mguzzy

Well-known member
Jul 8, 2015
662
OV, CA
Yeah ignore phosphates for the most part. If you control your chlorine then there is no algae to eat any phosphates that are present anyway. That is the concept here. A lot of pool stores use that as a short cut for algae control. Stay away from the darkside ;) For me I reduce my phosphates during my pool opening process in the beginning of the season since I have so many over hanging trees, then I don't worry about it the rest of the year. . from your landscaping it doesn't look like you would get much biomass contribution from the surroundings to worry about.

Yes that was some of the idea...the other is I see hegative edge pools but the pretty waterfall part is hidden...seemed better to reverse and I have adult kids and 5 year old kids so 2 depths good too.
It came out well. Would love to seem some close up pics of your cascades...

meanwhile here is what it reminded me of:

Travertine terraces of Pamukkale, Turkey (credit Wikipedia)

Cascadas de Agua Azul, Mexico (credit Wikipedia)
 

duraleigh

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Yeah ignore phosphates for the most part. If you control your chlorine then there is no algae to eat any phosphates that are present anyway. That is the concept here. A lot of pool stores use that as a short cut for algae control.
Well, actually, a lot of pool stores use phosphates to sell you something....period.

They have no clue what they are selling and they have no clue to it's effectiveness. I am saying you can ignore phosphates completely.

Algae food? Balderdash! (one of my favorite words) If there are no phosphates available in your pool, algae simply uses nitrates for their food source without missing a beat.

Chlorine is the answer to sanitizing and preventing algae from taking hold in your pool. Base your dosage on the FC/CYA relationship found in Pool School and focus on what's important.

It would be very helpful if you post your current test results like this

pH
FC
CC
CH
TA
CYA
 

iannecj

Member
Jul 18, 2019
9
Central Florida
Forum friends thank you, I have the FC dialed in now. I am having to run the pump still 12 hours and I have dialed my overflow in circulation down to a minimum. Good news is salt cell is maintaining salt levels at 60% with 12 hr run time. Probably in part because pentair told me to run higher salt levels so now I keep is no less than 3600. Also bathing load is way down after the 4th of july parties. Also, I turned off cell a few days and estimate my "demand" or usage is more like 1.5ppm per day so thats I guess how cell is keeping up.

My problem now is with what @mguzzy mentioned. All is great except I cant keep pH down and my Total Alk is down at 50. Due to aeration from overflow I would guess mainly. Since SWG output comes into upper basin and since only the bubble is a way to get water in the lower without the overflow spill wall I cant stop aeration and pH goes up even after a gallon of acid each week.

Here are my latest readings:
pH 8+ (taylor kit not precise here, could be even higher than 8)
FC 4.8
CC 0
CH 300
TA 50
CYA 70

So when we say we dont worry about TA in posts above, should I just keep increasing weekly acid dosage even if TA goes lower?
 

mknauss

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May 3, 2014
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Laughlin, NV
Once your TA goes much below 50, your pH can become unstable.

With constant aeration you are in for a acid / baking soda cycle. The design of the pool is causing it.
 

Jimrahbe

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Jul 7, 2014
14,020
Bedford, TX
Ian,

When you add acid, what pH level are you shooting for? I find that most saltwater pool like their pH to be about 7.8. Reducing the pH to 7.2 just takes a lot of acid and only lasts about a microsecond. It is better to only drop it back to say 7.7 ppm...

Have you though of adding an acid pump system that would add a little acid to the pool each day automatically? Not sure it would help with your low TA issue, but it should help keep your pH at a more constant level..

Thanks,

Jim R.
 

Newdude

Well-known member
Jun 16, 2019
773
NY
Reducing the pH to 7.2 just takes a lot of acid and only lasts about a microsecond. It is better to only drop it back to say 7.7 ppm...
Somwhere around 4 years ago i gave up the constant battle and just let it go. I figured whatever bad water conditions that would happen from the experiment would cost less to fix than the overpriced stuff i was using to fight the PH.

It leveled off at 8 and stayed there. It will fluctuate just a hair from time to time but is usually firm at 8. No eye irritations or other averse effects. Its been there ever since.
 

mguzzy

Well-known member
Jul 8, 2015
662
OV, CA
Forum friends thank you, I have the FC dialed in now.
...

My problem now is with what @mguzzy mentioned. All is great except I cant keep pH down and my Total Alk is down at 50. Due to aeration from overflow I would guess mainly. Since SWG output comes into upper basin and since only the bubble is a way to get water in the lower without the overflow spill wall I cant stop aeration and pH goes up even after a gallon of acid each week.
...
I wonder if there is anyone else with integrated water features that might have some input on this. So I was wondering if it's possible to tweak your pool plumping somehow so you can get flow to the lower pond without aeration.. perhaps a pipe from the rain thingy.. Or what kind of bubbler is feeding that lower pool. If it is a Venturi type return you could take the bubbler mechanism out or if its a jet, change the nozzle and it might act as a regular return. Just a thought..