Understanding intellichem and its options

[MattM]

My initial pool build design called for an intellichem w/ muriatic acid. The intellichem was just recently released and I haven't heard many reviews about it....PB is slated to order it rather soon. Better to skip it?

Also, found the following quote in the intellichem manual:
"Plaster pools and pools using salt-chlorine generators typically cause a slow pH rise
which must be managed. With IntelliChem, muriatic acid or carbon dioxide (CO2) is
dispensed into the filter system’s return water as needed until the Flow Cell pH sensor
detects the proper pH level. Using CO2 for pH control eliminates the need to handle and
store acid and can be a safer method. As CO2 gas is injected into the pool water, it
dissolves and creates carbonic acid. This weak acid is very efficient at lowering pH with
the added benefit of self-limiting if the CO2 is over-fed."

This would seem to be an endorsement of using an intellichem hooked up to CO2 canister as a complement to the intellichlor SWG.

Searching TFP, I found the following article which seems quite negative about the whole concept:
co2-as-a-ph-reducer-problems-with-ta-t39400.html?hilit=carbon%20dioxide

So, I'm curious what others think....intellichem worth buying? if we do get it, just stick with muriatic acid...I'm not sure how it gets loaded in and whether thats any safer than just pouring acid directly in the pool as needed.

 

[JasonLion]

I haven't heard of an IntelliChem shipping yet, though they are due right around now. PH control is available from a number of sources and most of them work very well. I would assume the Pentair version will be similar. All brands of ORP control tends to have quirks and problems in outdoor residential pools, such that they are almost never worth the trouble or expense. Also, CO2 is not the best PH control approach. Muriatic acid is better. Over the long term PH control with CO2 tends to make the TA go up, which can be problematic.

 

[PoolGuyNJ]

Intellichem is shipping.

I won't be recommending it's use with a salt cell. With salt cells, the CYA levels should be higher and this reduces ORPs effectiveness as a measure of desired chlorine levels. IntelliPH is better suited for use with salt cells..

I do like it when liquid and MA are to be used. Since this method uses less stabilizer, the ORP levels can be better trusted. It will reduce the need for handling of acid and liquid chlorine and makes it a simple task, roughly once a week or so, depending on the pool size. Even my wife or daughters could do it without messing it up, not that they would want to, mind you, being the little princesses that they are.

There are some caveats though.

The storage tanks and feed pumps really should be sheltered from the sun. UV rays can reduce the FC in the liquid chlorine and even though the hoses are pretty tough, they will fair better for longer periods without the sun beating on them.

Winterizing the sensors is a must. Freeze protection for this system does not exist and so, in climates that rely on an automation's freeze protection vs winterization, the Intellichem must be winterized. One good freeze will make for some expensive repairs otherwise.

IntelliPH has these same caveats.

These concerns also apply to Hayward's Sense and Dispense system.

Just like any other pool, a proper test kit is still needed. Once the system is dialed in though, it'll provide a pretty darned stable and reliable chemistry. Getting it dialed in does take some time though. Shutting it down for shocking periods is a good idea or she'll dump acid in the pool when additional liquid chlorine or bleach is used to boost the FC to shocking levels, since it tends to raise the pH.

Scott

 

[MattM]

Thanks for the feedback. It sounds like the reviews of the intellichem are not that great yet, although that might change over time. I was hoping for better. As far as consensus -- I'm sensing that It might work when used for liquid chlorine and muriatic acid, but if we have an SWG....the intelliph is really the right way to go? Fair enough. We'll be connecting up to an intellitouch too if that makes any difference.

If we go the intelliph route, that means getting pool balanced, then adjusting intellichlor long term dispensing rate, and afterwards setup the long term rate for the intelliph so that they mostly keep each other in check while maintaining the right amount of FC/etc?

 

[JasonLion]

Yep, that is the rough outline. There tends to be lots more detail when you are actually doing it

 

[PoolGuyNJ]

Not all that much with InteliPH. Once you know how much acid the pool will need, setting the dose per time slot is the hardest part. Since there is no pH sensor, regular testing is still needed. Acid demand, with new plaster, will change over the first year. After that, it'll stabilize. The use of borates should also reduce the amount of acid and dosing frequency.

Scott

 

[MattM]

As a quick check, I looked for more info from pentair about concerns about CYA with ORP sensors. I also re-read pool school and the note about CYA - "The biggest mistake that many SWG owners make is NOT having enough CYA in the water! This can create a lot of problems like high acid demand, algae outbreaks, cloudy water, or early cell failure." The TFP recommendation appears to be 70ppm.

Looking on the pentair forums, there is this post from a pentair tech -- http://poolfyi.com/forum/topics/the-eff ... cid-on-orp - The rep acknowledges that the intellichem is not as accurate with high CYA, but claims that CYA levels higher than 30 are not needed and indicates that the ORP has better accuracy if 30ppm CYA is maintained. "As you can see, at a 30ppm CYA level, there is 98% chlorine remaining versus 100% at a 70ppm CYA level – or a 2% increase over 40ppm. Above 30ppm, it’s not worth spending the extra money on CYA." "CYA level of 30ppm, your ORP reading should be about 677mv. However, if you increase the CYA level to 70ppm in the same body of water, your ORP level will drop to about 640mv. "

So, I'm still rather new to understanding pool chemistry, but is the reason for increasing CYA from 30 to 70 essentially just to allow SWG's to run at a lower rate and therefore preserve the life of the cell and/or variations in ph resulting from creating chlorine? I note that the non-swg tfp recommendation is for 30-50ppm. Is the pentair rep is directly attacking the advantage of a higher cya or ignoring some important aspects? I'm sure you guys have the real world experience to justify the 70 level, but I'd like to understand it better so I can clearly articulate why the CYA level that pentair designed the intellichem to operate at or under is inappropriate.

Note that our pool will be covered 90% of the time, and really only uncovered when we're swimming or vacuuming, which will probably be under 10hrs/week - which because recommended cya levels correlate somewhat to the amount of sunlight could indicate that our cya needs are also reduced. On the other hand, we're in san diego and will be operating the pool nearly year around.

Please excuse if the above questions are noobish...I'm really trying to develop a solid understanding of our pool needs.

 

[PoolGuyNJ]

If your pool has an automatic cover, and it sounds like it does or will, a cell equipped Intellichem will work fine with a CYA level at 30. Going beyond that really reduces the ORP's proper sensing range. Since the pool is covered from the Sun for so much of the time, the cell can make up the loss of FC when it is exposed without having to generate makeup. The difference in On time for the cell would be minimal but the cost vs IntelliPH is kind of steep.

Will the pool really be covered as much as you think?

Scott

 

[JasonLion]

Lower CYA levels require the use of more total chlorine. With a SWG that can have a significant impact on the lifetime of the SWG. High CYA levels tend to lead to a couple different minor problems, such as higher FC levels required when shocking, but having a SWG greatly reduces the likelihood of running into those same problems. Thus, you can run at an higher CYA level with a SWG and not have any more problems than someone without a SWG and with lower CYA levels.

Increasing CYA levels reduce the signal to noise level in the sensor output. As CYA goes up the noise eventually swamps out the signal and FC levels start varying more than you would want. There are some fairly dramatic sources of noise in an ORP system. For example sunlight lowers ORP readings by about 20 to 30, without any corresponding change in FC levels, effectively noise from the point of view of regulating FC levels.

 

[MattM]

Thanks for the feedback again.

Our pool design was centered around low heating costs and a long open season, so that we use 550ft of heliocool solar for primary heating(effective in san diego), an automatic safety cover in the darkest color from pool safe for passive heating whenever pool is not in use, and a heat pump (set to only be used a minimum temp can not be maintained via the other methods). The pump and solar will be running from 7am-5pm every day. Solar configured to 92 degrees, heat pump configured to 70.

I'm assuming 3.3hrs 3 times/week would be our average use of the pool - which is why I stated 10hrs open to sunlight per week, but that could increase in the summer and decrease in the winter.

Pentair is stating that the probes on intellichem should be assumed to need to be replaced every few years(no idea on cost). As for accuracy of the ORP, i believe the set point can be adjusted so that it is a little more conservative on when it activates the SWG. It sounds like as long as I never let the CYA ever fall below 30 and preferably keep it around 35, the accuracy of the ORP should not be too out of balance...but that it will never be as nearly accurate as manual FC tests.

 

[PoolGuyNJ]

ORP does not measure FC. FC is implied because of it's use as the sanitizer. Though a couple pounds of non chlorine shock, AKA MPS, in the pool and watch the ORP level jump! You may be able to oxidize anything but it won't sanitize. They are two different functions that chlorine does.

CYA reduces the range a sensor can detect Actual numbers will be different but the following example may help to explain it a bit more clearly.

If, at 3 ppmA of FC and CYA of 30 yields a 700 mv reading and a drop of 1.5 ppm yields a 500 mv reading and the sensitivity is set to +/1 75 mv, if the CYA were boosted to 70 ppm, and FC to 4 for a reading of 700, the drop to 2 ppm FC might only be 5 mv. A 5 mv sensitivity is too fine to maintain a consistent FC level and results in improper dosing.

This is why I don't like cells on Intellichem. I like cells to last. The cell has an easier time maintaining a proper level with the CYA higher than an ORP sensor can handle.

Scott

 

[JasonLion]

ORP sensors can be way wildly wrong sometimes, which can completely rule out their use in some situations. For example ORP falls when there is hydrogen gas dissolved in the water. SWGs produce both chlorine and hydrogen gas. Depending on how much of the hydrogen gas dissolves the ORP may go up, or it may go down, the longer the cell is energized. If, in your pool, ORP goes down when the SWG is running because of the hydrogen issue, then ORP based control is completely useless.

Sensors are usually replaced every other year and seem to cost between $150 and $250 each, though that has been going up.

 

[bk406]

I guess i'll ad my 2 cents, i usually do

Just my opinion, others may disagree.
My take on it is that its just something else that needs to be maintained and will break. I have minimal automation; a Pentair easy touch and an IC-40. I set my CYA at ~50 ppm and set my IC-40 at 25% or so, give or take, run the pump 10 hours a day, and my Fc stays around 4 to 5. I test it maybe every other day, sometimes every 3 days, and its always right where it should be. I keep my TA at 60-70. I know this my be unbelievable, but i've not added ONE drop of acid to my pool in 2 years. Keep your CYA around 50, and keep your TA on the low end, test every other day with FAS-DPD, and you will have few problems.

 

[MattM]

Well, honestly, now I'm just confused again....my understanding is that since our pool will be covered so much, it should almost be considered as if it was an indoor swg pool? Given the dual benefit of the cover which protects against containments and sunlight, I would expect our SCG to be running at a minimal rate -- even with CYA between 30-40. Since there is very little chlorine being generated, there would also likely be very little need for an intellichem or intelliph to dump acid, but the intellichem could at least passively monitor and respond automatically when required.

The question becomes -- do the other accuracy issues that would discourage use of an ORP pertain here? chlorine levels won't decrease much so orp levels are generally constant. The hydrogen comment could cause variation and is interesting, but I haven't heard anyone suggest that ORP's shouldn't be used for indoor pools w/ SCG so I'm wondering how relevant of a problem that is.

bk406 makes a good point that a well maintained pool might have minimal if any need for an intellichem or intelliph unit regardless so why install either -- however, I'm not sure if this is the approach to take or if I'll be in a similar case. But, it certainly brings manual dosing back into the picture.

The concerns I have the most are for the covered pool situation is if despite a relatively minimal amount of normal chlorine generation or acid need, if the ORP would be more likely to bring instability than stability....and especially if the probe aging is handled gracefully or would cause a significant disruption once every few years. If despite the ideal environment of the pool which mimics indoor conditions, the ORP would generate more problems than it solves....than we'll skip it. If we went with the intelliph, the dispense rate would probably be so low that I'm not sure it is worth it except for specific events which it wouldn't detect on its own.

 

[PoolGuyNJ]

Hydrogen, because of its low weight and size, should gas off fairly rapidly. I can't see it building up in the pool water. It will make it through the cover, just as helium makes it through a balloon, albeit significantly slower than that process because of the cover's thickness. Once exposed to the atmosphere, that rate would would increase substantially.

By and large, with the system running and the cover closed for any extended period of time, the cell will be off since the ORP would be stable. Without the cell being on, no hydrogen will be produced by the cell. If the cover were opened for a period of time during the day, say, a Saturday, then I could see the cell being on trying to make up for lost FC/lower ORP readings, especially since cells are relatively slow. The CYA will help slow the FC losses but activity will generate demand. The hydrogen the cell made has no stabilizer and would either recombine with oxygen or gas off.

Lets suppose the system has caught up prior to it's system off time. It is unlikely to be on much until the cover is opened again. If it was generating up until the system shuts for the night, it won't be on long when it starts up the next morning since the cover would be closed and anything generating a demand is blocked by the cover.

I don't see you opening and closing the cover that often or it being closed quite as much as you seem to think. I suspect it will be open more. You will find out there is such a thing as pool friends or Summer friends. This will keep the pool open more and raise the food/beverage bills . I've seen this before. Ensure the cell is big enough to accommodate increased demand though in case the cover is opened and the bather load is greater than anticipated. I wouldn't hesitate at putting a 60K gallon cell on a 20K pool with Intellichem. Without Intellichem, I would normally only spec a 40K unit.

Scott

 

[MattM]

Scott,

K...my pool builder thinks the intellichem is a good solution for us and has agreed to put in an ic60 rather than the ic40. He also said he was going to have a pentair rep supporting us directly during the initial setup of the intellichem. I spoke to the wife unit and we agreed that the cover would stay open only when someone is actually in the pool. We paid quite a bit for the automatic safety cover with the recessed embedded undertrack + tiles so I'd be quite frustrated if weren't making constant use of it.

I'll just have to figure out the right settings to put into the android simple pool app for chemistry ranges....I'd like to use the tfp bbb swg parameters, but I assume with just the CYA and FC levels ranges closer to non-swg settings.

Matt

 

[PoolGuyNJ]

I don't think you'll have a hard time with getting it dialed in. Having a rep available is one of the reasons I like dealing with Pentair. I have to assume your PB will feel similarly.

Time will tell as to how often the cover will be opened and closed. Balance wear and tear too. Excessive opening and closing can shorten equipment life and these systems are somewhat costly to repair. Intentions and goals are great but setting them and meeting them for most people are two different things. In that, I am no different than anyone else.

Scott

 

[acaciolo]

hey guys,

I've installed 24 intellichems on the pools we built here in pa, and I can tell you, I am 100% happy....and so are my customers! I've had to change the ph sensitivity from low to high on the menu, but other than that, they just work perfectly. and I get to monitor my customers levels back at my office (on the ones that have the iPhone control installed)

I give is a strong endorsement and have it specd on all of our upcoming pool builds. feel free to write or call me with any questions, as we have gotten to know this well.

ps. we are running cya at 40.

tony c

 

[MattM]

acaciolo: thanks for the feedback! I'm curious why you felt the need to set the ph sensitivity to high? When I read the manual, the default low setting seemed to make sense -- especially with regard to avoiding dispensing acid that might later cause the intellichlor to run more than required. Did the intellichem just take too long to accommodate rapid changes to ph w/o the high setting?

Also, are you doing anything different than the general pentair recommendations when determining the ORP set point? We'll have a pentair tech out here during the startup and I want to make sure he chooses a conservative yet accurate set point.

 

[PoolGuyNJ]

I hope you got a good test kit like a TF-100 or K2006.

Scott