New pool finished about a month ago; could I have some help please...

[Nezil]

Hi everyone, as the title says, our pool was completed last month, and overall we're really happy with it. Unfortunately it's quite cold (even here in San Diego) currently, and with the current gas prices, it's prohibitively expensive to heat. We're looking in to solar thermal heating, and that should help us extend the usage a little more than only summer. We have used the spa a couple of times, because heating that is a manageable cost, and after having spent so much money having the pool built, it hurts to just not use it at all!

So the details of the pool are:

• 18' x 36' - 6' deep at the deep end, 3.5' deep at the shallow
• 7' x 7' spa, offset by 18" in height, and length, and about 6" in width
• 2 spillways from the spa to the pool
• Blue Surf Pebble Sheen + Abalone finish
• 2 x Clark Synthesis Diluvio underwater speakers

Pentair Equipment

• EasyTouch 4, upgraded to EasyTouch 8 (thanks to posts on this site)
• IntelliChem with pH and ORP sensors
• Acid Tank with Dosing pump
• IC40 Salt Cell
• Mastertemp 400 heater
• IntelliFlow3 VSF pump
• 3 x IntelliBright 5G Color Changing Lights (2 in the pool, one in the spa)

Taylor K-2006C + K-1766 test kits

For the first month, the pool company did not add salt or enable the IntelliChem. They visited once / week to check pH and Chlorine, adding both Chlorine and Muriatic Acid during those visits. At some point during this first month, I turned on the IntelliChem just to get a read of pH and ORP in the ScreenLogic app. It noticed, as you might expect, that the ORP value jumped high when the pool company added liquid chlorine, and then slowly trended down over the next few days. By the time their visit on Friday hit, the ORP value was very low. The pH on the other hand drifted from 7.5 up to about 8.2 over that same time period.

Last Friday was the last 'free' visit from the pool company, and they added salt to the pool and switched on the IC40. They intentionally added less salt than they expected to need, so as not to over dose the pool. I've been monitoring the salt level reported in ScreenLogic from the IntelliChem since then, and have added the remaining two bags they left behind (10 total so far) because the salt cell reported the salt level so low that it wouldn't produce Chlorine.

At the same time during that visit, we also tested Alkalinity and Calcium Hardness, getting results of 70 and 150 respectively. Baking Soda was added at that time, and I've since tested the Alkalinity yesterday, getting a result of 110.

I've done some reading about LSI, and the IntelliChem and EasyTouch, as well as the ScreenLogic app have internal calculators to do this for you based on partial manual measurements. Most of my questions at this point are related to water quality parameters and testing.

Main Questions

• As mentioned above, we have an IntelliChem reporting pH and ORP values, and controlling Acid and Chlorine generation respectively based on these readings. Aside from periodic sanity checks, do I really need to measure pH and Chlorine with my test kits?
• What is ORP, and how is it related to Free Chlorine, Combined Chlorine etc?
• What is the difference between the Chlorine tests in K-2005 and K-2006; why is the K-2006 version preferred?
• I notice that temperature has a very big impact on LSI, and if so, what are the optimal Alkalinity and Calcium Hardness levels for a pool with spa in my region (San Diego)?

My initial plan was to target:

• 110 ppm Alkalinity
• 300 ppm Calcium

These two values in the summer, with a pool temperature of 82 would get me an LSI of 0.01, and in winter, with a water temperature of 55, raising the pH target to 7.6, would land me at an LSI of -0.14. These numbers looked great, until I thought about the fact that I have a spa and heater. The water temperature in this case goes up to 0.19, and I worry about scaling, even though I'm within the +/- 0.3 range.

I wonder then if a balance of 250 ppm Calcium would make more sense, yielding the following:

• Winter 55 temp (7.6 pH) = -0.22 LSI
• Summer 82 temp (7.4 pH) = -0.07 LSI
• Spa 100 temp (7.4 pH) = 0.11 LSI

Probably the worst possible use case is heating the spa in the winter, because the pH is unlikely to change from 7.6, and that takes me to 0.31 @ 250 ppm Calcium, and 0.39 @ 300 ppm Calcium.... Thoughts?

Additional Question

How important is a sacrificial anode in a salt water pool. Clark Synthesis, who makes the underwater speakers that I have, suggests that it's very important when using their speakers because the magnets in the speakers attract dissolved or small iron particles, which then rust in the water. The speakers themselves do not rust, but the suspended particles all collect in the same place, and can create unsightly stains as a result.

I spoke to our pool builder about this, and he had never heard of fitting a sacrificial anode to pool plumbing, except for the case where low voltage LED lights are used, and there isn't a bond wire from the light to the rest of the equipment. In this case it's not really a sacrificial anode, it's a water bond wire of some kind.

They said that they could fit whatever I wanted in to the plumbing, but for whatever reason we never got around to it and the project has completed. I've ordered a 2" T type zinc anode though, and plan to fit it just after the pump. I just wondered if this was really common practice or not.

Thanks in advance guys!

 

[Bperry]

Main Questions

• As mentioned above, we have an IntelliChem reporting pH and ORP values, and controlling Acid and Chlorine generation respectively based on these readings. Aside from periodic sanity checks, do I really need to measure pH and Chlorine with my test kits?

Welcome to TFP. That’s a lot of questions all packed into a tight space but I’ll try. The first item to know is that TFP isn’t a generic pool website and has its own specific guidelines for pool care that oddly enough work very well but are different than any other place I’ve found. Take a look through the website articles for pool school and it’ll answer a lot of questions in advance.

You’ll probably find the ORP isn’t going to be very accurate as the stabilizer (CYA) level increases. You’ll have to ask someone else why that is but just be aware not to trust it very much. So yes you would be wise to measure those both very frequently at least in the beginning until you find how the pool responds. After a while you might be able to back off to measure a few times a week.

• What is ORP, and how is it related to Free Chlorine, Combined Chlorine etc?
• What is the difference between the Chlorine tests in K-2005 and K-2006; why is the K-2006 version preferred?

The K2006 uses a FAS-DPD chlorine test process which is accurate up to something like 50ppm. The K2005 uses a different test which isn’t all that accurate but give generally close values up to 5ppm (some say even 10ppm)

• I notice that temperature has a very big impact on LSI, and if so, what are the optimal Alkalinity and Calcium Hardness levels for a pool with spa in my region (San Diego)?

TFP uses a different thing called CSI which is similar but different. Take a look through the pool school articles to get an idea of the difference.

My initial plan was to target:

• 110 ppm Alkalinity
• 300 ppm Calcium

These two values in the summer, with a pool temperature of 82 would get me an LSI of 0.01, and in winter, with a water temperature of 55, raising the pH target to 7.6, would land me at an LSI of -0.14. These numbers looked great, until I thought about the fact that I have a spa and heater. The water temperature in this case goes up to 0.19, and I worry about scaling, even though I'm within the +/- 0.3 range.

Try switching to the CSI tracking and check out the “pool math” app and it’ll help you calculate all of the values according to TFP guidelines. Those target values for TA and CH are more for trichlor chlorinated pools. With a salt system your TA would be better around 60-70 which will help slow the natural pH rise.

I wonder then if a balance of 250 ppm Calcium would make more sense, yielding the following:

• Winter 55 temp (7.6 pH) = -0.22 LSI
• Summer 82 temp (7.4 pH) = -0.07 LSI
• Spa 100 temp (7.4 pH) = 0.11 LSI

Probably the worst possible use case is heating the spa in the winter, because the pH is unlikely to change from 7.6, and that takes me to 0.31 @ 250 ppm Calcium, and 0.39 @ 300 ppm Calcium.... Thoughts?

Ha. The pH will change quite frequently by rising. It’s just your intellichem system will dose more acid to lower it, which will also drive the TA down over time so watch the TA carefully. You’d be better off changing the pH target to around 7.8 when necessary.

Additional Question

How important is a sacrificial anode in a salt water pool. Clark Synthesis, who makes the underwater speakers that I have, suggests that it's very important when using their speakers because the magnets in the speakers attract dissolved or small iron particles, which then rust in the water. The speakers themselves do not rust, but the suspended particles all collect in the same place, and can create unsightly stains as a result.

The anode won’t do anything in your pool, but most people say if it makes you feel better to go ahead an install.

I spoke to our pool builder about this, and he had never heard of fitting a sacrificial anode to pool plumbing, except for the case where low voltage LED lights are used, and there isn't a bond wire from the light to the rest of the equipment. In this case it's not really a sacrificial anode, it's a water bond wire of some kind.

They said that they could fit whatever I wanted in to the plumbing, but for whatever reason we never got around to it and the project has completed. I've ordered a 2" T type zinc anode though, and plan to fit it just after the pump. I just wondered if this was really common practice or not.

Thanks in advance guys!

 

[Nezil]

Thanks very much for the response @Bperry, this is helpful.

I've done some more reading on the site, and can see that CSI is more accurate than LSI. I'll post some separate, shorter, posts with follow up that target specific topics related to water chemistry.

 

[Newdude]

I'll post some separate, shorter, posts with follow up that target specific topics related to water chemistry

Keep anything related here so we can follow your whole journey. And Welcome.

 

[Nezil]

Oh, OK... I was worried that my initial long post would scare some folks off...

So my concern I think, at a high level, is that IntelliChem is controlling based on pH and ORP, and the TFP recommendations are a) based on Free Chlorine, and b) include a recommendation for a Cyanuric Acid level that will prevent the IntelliChem from being able to read ORP effectively (> 30 ppm). The IntelliChem also has a limitation (as far as I can tell) that makes it impossible to target higher than 7.6 pH.

It would be possible for me to remove control of the SWG from the IntelliChem, and then set it manually, but my feeling, and I might be wrong, is that continuous testing within the limitations of the IntelliChem is preferable to infrequent manual testing even with its greater flexibility.

Is there a TFP approach that is compatible with these IntelliChem limitations?

 

[ajw22]

You need to choose to follow TFP Methods or the IntelliChem method.

If the IntelliChem was more trouble free then TFP methods we would be recommending it. Look at the name of this site.

Trying to mix and match pool care methods is rarely a recipe for success.

Should you get frustrated with the Intellichem we will be here with an alternative.

Pentair IntelliChem - Further Reading

www.troublefreepool.com

 

[jliddil]

Were they brushing every day? Have you backflushed/cleaned the filter?

 

[Nezil]

That's a very concise response Allen, and the Further Reading link was very helpful. It seems like one option would be to remove control of the SWG from the IntelliChem and I would then be able to follow the TFP approach whilst still having acid controlled by the IntelliChem.

I'll have to think more about what I'm going to do. It's confusing that there are two quite different approaches, especially when they don't deviate that much from each other; ultimately they're attempting to control the same two things - scale vs corrosion and sanitation. It would be helpful if there was a summary of the differences of the approaches... I'll try to do that here:

Pentair IntelliChem Limitations

• Can only set pH between 7.0 and 7.6
• ORP used to measure sanitation level, which may be affected by other chemicals in the pool, particularly Cyanuric Acid
• Cyanuric Acid must therefore be kept < 30 ppm
• Goal is to achieve an LSI 'Water Balance' of 0, rather than the more accurate CSI calculation
• IntelliChem's measurement setup requires an amount of flow that may be incompatible with a system that's configured for long durations of lower pump speed

If Cyanuric Acid is either not used, or used at a low level of < 30 ppm, the risk is that Free Chlorine will be lost due to UV exposure very quickly. Is this an issue if Chlorine is being added continually anyway?

I can totally see why Cyanuric Acid would be essential if you're only adding Chlorine once / day or even every few days, but in a SWG system, is this only necessary if the SWG cannot produce enough Chlorine to keep the level of Free Chlorine high enough?

Issue with converting between Pentair's IntelliChem and TFP Approach with a SWG

• TFP recommends Cyanuric Acid levels that are higher than compatible with the IntelliChem's ORP testing method. Reducing CYA to < 30 ppm will requires changing a significant amount of water

Does this seem accurate so far? Am I missing anything?

 

[Nezil]

Were they brushing every day? Have you backflushed/cleaned the filter?

Yes, brushing was done every day, but to be honest, I watched, and there wasn't much dust or loss of pebbles from the finish at all.

I have not cleaned the filter. It's a Pentair Quad DE, which is sort of a hybrid DE / Cartridge filter. Is there some reason why I'd need to clean the filter after such a short period of time?

 

[Nezil]

One thing I have seen mentioned in other threads, is that some TFP members recommend a pool pump schedule that differs quite a bit from established norms. These recommendations might also be incompatible with IntelliChem as mentioned above in my limitations list.

Could someone detail what these recommendations are? I remember reading about 20 hours of very low flow, followed by a couple of hours at higher speed to clean, and purge a spa etc. I'd be interested to hear the thoughts on this and couldn't find anything in the Pool School section.

 

[ajw22]

One thing I have seen mentioned in other threads, is that some TFP members recommend a pool pump schedule that differs quite a bit from established norms. These recommendations might also be incompatible with IntelliChem as mentioned above in my limitations list.

Could someone detail what these recommendations are? I remember reading about 20 hours of very low flow, followed by a couple of hours at higher speed to clean, and purge a spa etc. I'd be interested to hear the thoughts on this and couldn't find anything in the Pool School section.

Determine Pump Run Time

To figure out how many hours you need to run your pump, you need to know how fast your pump works. You can find this here.

www.troublefreepool.com

 

[Nezil]

Thanks Allen, I did find that page, but was more interested in the specifics of a very low flow rate for a long duration, which is not specifically covered in that page.

 

[ajw22]

Thanks Allen, I did find that page, but was more interested in the specifics of a very low flow rate for a long duration, which is not specifically covered in that page.

Once your pump has achieved the necessary daily sanitation and skimming anything else is personal preference.

I run my pump 24/7 as I see no reason not to. It’s that simple.

 

[Nezil]

Once your pump has achieved the necessary daily sanitation and skimming anything else is personal preference.

I run my pump 24/7 as I see no reason not to. It’s that simple.

Thanks!

 

[ajw22]

I have not cleaned the filter. It's a Pentair Quad DE, which is sort of a hybrid DE / Cartridge filter. Is there some reason why I'd need to clean the filter after such a short period of time?

You should have objective criteria for when your filter needs cleaning.

The standard recommendation is to note clean filter pressure at a specific pump RPM and when the pressure increases by 25% to clean the filter.

I have found it difficult to see a 25% PSI rise when flow is low and thus PSI is low. My IntelliCenter/Intelliflo shows me GPM flow and I clean my filter when flow drops about 5 GPM.

 

[Nezil]

Great advice Allen. I do have the PSI gauge on top of the filter, but as you say, at low RPM / GPM, it's tough. I don't currently have a low flow schedule, but I'm considering it. I have noted the pressure at the standard flow, and it hasn't increased at all yet.

That's hardly surprising because there has been almost zero load on the system. We've not used the pool at all (too cold), and there aren't really any trees near the pool to drop any significant amount of leaves. What few do fall in (literally ~ 10 / week) mostly get caught in the skimmer or pump baskets.

 

[ajw22]

On the side of my filter I have written with a Sharpie RPM, clean PSI, clean GPM for 1700 RPM, 2400 RPM, 3400 RPM. That lets me easily compare current performance to best clean performance.

 

[Nezil]

You also have a Pentair DE filter, so the advice is particularly relevant to me. Thanks!

 

[Mdragger88]

@Nezil ,
Everybody’s got you pretty covered but I wanted to address this

I can totally see why Cyanuric Acid would be essential if you're only adding Chlorine once / day or even every few days, but in a SWG system, is this only necessary if the SWG cannot produce enough Chlorine to keep the level of Free Chlorine high enough?

It’s not that your particular swg (which is nicely sized for your pool) can’t keep up necessarily, but the recommendation also exists because all swg cells have a finite life span (usually around 8-10k hrs @ 100%).
So, the more you protect the fc the cell produces, the less the swg has to run (hrs or %) & the longer your cell will live.
The cell produces fc very slowly over a long period of time (think of it like an iv drip). You don’t want the sun burning that off as fast as it’s being produced, which is what happens with lower than recommended cya.
If the pool generally has a cover on it when not in use then the cya needs are lower as the cover is protecting the fc as well.
Does your pool have a cover? If so, what kind?
Also, trying to heat an outdoor pool without a cover on a regular basis will definitely put you in the poor house, its like burning $$.

 

[pjt]

Baking Soda was added at that time, and I've since tested the Alkalinity yesterday, getting a result of 110.

The baking soda wasn't needed. TA of 70 is great. You'll probably end up with a TA between 50-70 and pH in the high 7s, which is just fine. IntelliChem seems like a solution in search of a problem.