New Pool - Traditional vs. TFP method in www.troublefreepool.com/calc.html

[nerdindenial]

Hi,
I'm a new pool owner with a new (August 2023) saltwater pool as described in my signature and as seen in photos in the Introduce Yourself thread.
I setup my pool chemistry as recommended by the builder (he wasn't very specific about CYA), which ~agrees with the "Traditional Pool" method dropdown box selection in www.troublefreepool.com/calc.html.
The water has stayed very clear, but I now notice that if I switch the dropdown box to "TroubleFreePool.com" the chemical recommendations change considerably.
So my question to you experts is whether I can roll with this chemistry or I need to switch to the TFP method and why?
Or can I just make smaller adjustments to today's levels shown below?
I hope this isn't a dumb question for the TFP forum
The installer programmed the pump to run at about 3000 rpm or higher (2 HP+) from 7am to 4pm only (electricity costs 70c/KWh from 4pm-9pm, but is cheapest overnight). Two of these hours spill over from the spa into the pool. So the pump is off for 16 hours per day.
Noise from the pump is not an issue, because the pump is a long way from anyone's house.
Power cost is not a big issue, because we have excess solar capacity.
Thanks!
LEVELS
FC: 5
pH: 7.5
TA: 120
CH: 280
CYA: 75
Temperature: 58 degrees F (no one is swimming between Nov 15 and March 15).
NaCl: 4000 ppm (Taylor K-1766), but the Intellichlor IC40 reads 3000 ppm and doesn't want it below what it calls 2800 (probably 3800 in reality).
I am only running the SWG at 10% in Winter because with the cover the pool uses hardly any chlorine - as the builder predicted.

 

[kimkats]

Well done on getting and using one of the good test kits! You are WAY above the curve stating out like that!

I would use the TFP levels. The reason is TFP levels are all science based unlike the traditional levels. Here is a link to just one of the many threads in the "Deep End". There are many more. Dive on in to learn the hows and whys of the TFP levels: Pool Water Chemistry

 

[Newdude]

So my question to you experts is whether I can roll with this chemistry or I need to switch to the TFP method and why?

You need to switch to the 'nerdindenial' method, which factors your specific pool type, chlorination method, and fill water. The good news is you can make minor tweaks to where you're at.

The industry has a one size fits all approach for everyone in the land. Their levels are assuming tab/puck chlorinating which is a different equation than your SWG. For example, when using tabs, they are stabilized with CYA(cid). Your PH will be low and the TA will follow. To combat that, they recommend TA on the higher side (120) to help pull the PH up. The PH rec is in the low 7s, where it will like to be with tabs. The problem is that the CYA in the pucks constantly raises the FC needed to sanitize at the same level and it quickly becomes unmanageable without a couple large water exchanges a season.

So we reccomend using liquid chlorine or the SWG which won't require ever increasing FC levels. We have reccomended levels for each method based on how the pool will respond to them, and also off shoots for fill water and pool type.

With the SWG, most need longer run times (more surface aeration) than the other two, which will raise the PH. With the PH wanting to be high, we reccomend a high 7 to help fight it less. Lowering the TA to the lower range (60) will help keep the PH down.

CH adjustments are based upon pool type and fill water. High rain areas have a forever decreasing CH, high CH fill areas have the opposite. People in the middle are, well, in the middle.

The average CYA needed for SWGs is 70, you'll probably need a little more in sunny San Diego once the sesson gets going. (Road test how well the FC holds and keep.us posted). Also always round up the CYA to the next 10. Call yours 80 and its good to go as is. Maintain the FC appropriately so it never sniffs minimum at its lowest point of the day

NaCl: 4000 ppm (Taylor K-1766), but the Intellichlor IC40 reads 3000 ppm and doesn't want it below what it calls 2800 (probably 3800 in reality

The cell uses conductivity to determine salinity. Any other metals besides salt (calcium for example) can skew the test some, as well as temperature. Trust your K1766 and as long as the cell doesn't throw errors, let it ride. I would normally exchange water at 4k salt but with the cell reporting much lower, I wouldn't want it to think it's too low. So I'm a bit torn here.

The installer programmed the pump to run at about 3000 rpm or higher (2 HP+) from 7am to 4pm only (electricity costs 70c/KWh from 4pm-9pm, but is cheapest overnight). Two of these hours spill over from the spa into the pool. So the pump is off for 16 hours per day.

Forget all that. You run the pump to perform a specific function. Skimming, chlorone production, heating, etc.

Start with low RPMs and increase it by 100 at a time. Note when each of your functions start to work and add 100 or 200 RPMs to that to account for the filter getting dirty and slightly restricting flow. That is the speed you need for that function. The higher speed functions run the lower speed functions by default. (If you're heating for 6 hours, the SWG and skimming work too, etc etc).

Report back with the various speeds needed.

 

[nerdindenial]

Thanks for the replies! I have posted 6 more pictures in the Introduce Yourself thread showing equipment details and water clarity (and the turtle mosaics).
I am currently adjusting the TA downward and the FC upward to get into the ranges that you suggested.
Due to the watertight cover and the type of landscaping, this pool gets very little ingress of rain and organic material.
The tap water does have a LOT of dissolved minerals, which probably explains the errant SWG salt level readings (although it came up from 3000 to 3300 after I ran it at 100% for 5 hours).
Setting a lower TA and higher pH should help reduce the amount of acid I need to add every week.
In the winter the chemistry stays fairly static with the cover on and the SWG running at 20-30%, except that the pH has been rising from 7.5 to 7.9 or more every week.
I don't use the gas heater (costs $7 per degree) and the skimmer doesn't have much to do (catches a few honeybees every week).

This picture shows the current pump RPM settings for 8 hours a day (the pump runs fastest for the 2 hours of spillover from the spa into the pool).


Thanks again for your help and I'll post again once I get the chemistry dialed into TFP values for a while.

 

[nerdindenial]

I linked my profile to my PoolMath logs from the app.
I got the TA down with lots of acid and aeration, but now need to lower the pH (will add sodium carbonate later today to get the CSI back in range).
FC is up to 17 (I ran the generator too long) - is that even safe to swim in?
We will have some warm weather next week and I might want to heat it up to swim.
I also ordered 50 pounds of CaCl2 to increase the CH.

 

[Newdude]

FC is up to 17 (I ran the generator too long) - is that even safe to swim in?

Up to 40% of your CYA level (slam FC) is safe for swimmers and equipment. Always round up (51-59 =60) so call your 58 a 60 and the pool is safe to 24 FC.



The high FC also invalidates the PH test unless you're using a digital meter. Wait for the FC to fall below 10 to check PH.

also ordered 50 pounds of CaCl2 to increase the CH.

What is your fill water CH ? If it's high, it'll increase quickly on its own.

 

[ajw22]

You can’t measure a TA of 75 or a CYA of 58.

Your TA is 70 or 80. Which?

We round up CYA. Yours is 60.

Dont try and dial in a specific pH or TA. You can not hit a moving target.

Your pH is fine. Let it rise naturally. It will.

A CH of 260 is fine.

Your CSI is fine for this time of year with low water temp. You adjust for CSI this time of year and things will get it too high when the water warms in the summer.

 

[nerdindenial]

Thanks for the replies. I subscribed to the premium PoolMath app so I could get unlimited cloud log storage.

After adding the soda ash I have the pH and CSI back in range. Of course the TA crept up to 90 as AJW22 alluded to.

I measure pH using an ORAPXI 7 in 1 digital meter. It says the salt level is 3700 vs 3000 from the SWG and 4000 from the Taylor Test kit.

The CH of the pool has been rising about 10 ppm/month since I got the watertight cover on November 1st and at the same time the weather cooled off.

The CH of my tap water measures at 120 and is very good at leaving white deposits around the house. This tap water supply is a changeable mixture of desalinated water, reservoir water, and river water.

I have a supply of CYA and CaCl2 coming from Amazon tomorrow; not sure if I should use it.

 

[ajw22]

I have a supply of CYA and CaCl2 coming from Amazon tomorrow; not sure if I should use it.

Don’t make any further changes.

Everything is ok.

Wait until the water warms up in a few months before you tinker further.

Just maintain your FC and keep pH in the 7s.

 

[Ahultin]

Howdy neighbor!
our pool is ~half the size of yours and does not get full sun so not a direct comparison but, I run the VSP pump at @1200rpm (which is quiet and costs very little) 24hrs a day. Spa spillover runs 3x per day for 15m. I try and keep the CYA ~70 and tend to #teamrunhot on the FC level, running it up around 10 with a fair amount of time spent in the low teens. Currently the SWG is at 5%. During the first yr, i added some calcium at times which i wish i had not done as once we reached about a yr, the CH level has been steadily rising due to the fill water hardness. I have learned to pay less attention to the individual PH number, its settled in the high 7's, and watching the CSI to keep it slightly negative. Despite the horror stories going in, my pool has been very trouble free (post construction lol)
I feel blessed to have stumbled on tfp prior to first fill.

 

[nerdindenial]

Howdy neighbor!
our pool is ~half the size of yours and does not get full sun so not a direct comparison but, I run the VSP pump at @1200rpm (which is quiet and costs very little) 24hrs a day. Spa spillover runs 3x per day for 15m. I try and keep the CYA ~70 and tend to #teamrunhot on the FC level, running it up around 10 with a fair amount of time spent in the low teens. Currently the SWG is at 5%. During the first yr, i added some calcium at times which i wish i had not done as once we reached about a yr, the CH level has been steadily rising due to the fill water hardness. I have learned to pay less attention to the individual PH number, its settled in the high 7's, and watching the CSI to keep it slightly negative. Despite the horror stories going in, my pool has been very trouble free (post construction lol)
I feel blessed to have stumbled on tfp prior to first fill.

@Ahultin Thanks for the very useful data.
We are having 5 days in the mid-70s in San Diego now so I added CYA and heated the pool to 80 degrees.
I'm glad this forum caught me before I added calcium, because it costs about $700 to refill my pool.
pH is back up to 7.8 again and I am keeping the SWG off because FC was 17 on the last test.
I will take measurements again on Wednesday and post the log.
Pool contractor made a few mistakes and took twice as long as he could have, but the real cost overrun was in the landscaping/decking/drainage - it costs a lot to cover an entire 1/4 acre backyard plus side yards plus deep drainage pipes out to the street.