Can adding a lot of calcium chloride at once reduce FC??

[mgtfp]

My thinking was to have measurable quantities in a bucket the people have at home. And ideally two of them. Anything around and below 1g will be difficult to weigh, and buckets around 10L are relatively common. No idea what is common on the other side of the Pacific.

Another thing is: We are thinking about impurities as a potential cause. How homogeneous are those impurities distributed in a bag of CaCl2? Probably don't want to go to microscopic for that reason.

 

[SoDel]

Why not conduct an experiment? Fill up two buckets with pool water which will have identical chlorine level. Then add a reasonable amount of calcium to one bucket and not the other. Then test the FC level in both buckets every 15 minutes or so.

I had similar thoughts (great or maybe strange minds think alike lol) but I’ve already done the experiment in my pool (albeit, in a very uncontrolled way). Referring to my notes, on 6/10/22 FC 7.5, 6/11/22 FC 7.5, 6/13/22 FC 7.5, 6/14/22 FC 7.5 added 10 lb CaCl2, 6/15/22 FC 5.0 (all testing done around 0700 each day listed). My FC is always pretty steady, so the 2.5 ppm drop caught my attention, but at the time I don’t recall linking it to the CaCl2. Fast forward a while and I did see anecdotal reports that this sometimes happens but from the chemistry it should not happen. It was just seeing this thread that got me to thinking it must be some impurity, assuming it really can be attributed to the CaCl2 and not some other coincidence.

Unfortunately, the bag of the particular CaCl2 I used was “it” so I don’t have any more of exactly the same whatever it was to try again. I don’t remember what brand it was but picked it up at a local pool store and I remember it was $18 for a ten lb bag.

If the working theory is an impurity (seems it has to be) then we need a sample from someone who has experienced this phenomenon and has some more of the exact same stuff left.

But for the heck of it, I do have an unopened box of a different brand of CaCl2 I bought from Amazon to have on hand to get ready for winter, and if I get the chance later today I’ll try various additions in 5 gal pool water to see if anything happens from that. Why not?

 

[SoDel]

I like the idea but should we target a more realistic estimated rise in ppm? 5g in 10L would generate an expected increase of 595 ppm. I know I was targeting about 100 ppm increase when I noted my loss. That would equate to .85g in 10L. (Someone check my math).

I think it’s all good even with a large rise in CH. I’ve been told by a couple of people who really seem to know what they’re talking about that CaCl2 absolutely does not affect FC. A large amount of whatever impurity is theorized to exist is good — should produce a result. If it does not, maybe that says something too.

In scanning my old notes, I also notice a slight FC increase the day after adding acid. It may have been you (or someone) who suggested maybe the SWG has something to do with all this calcium stuff because that also doesn’t make sense from the chemistry?

 

[duraleigh]

I spoke with Wayne Ivusich from Taylor Technologies yesterday. He has been with Taylor for eons. Many of you may have met him at trade shows. Wayne left NO wiggle room, "FC and CH are completely unrelated. What you (Dave) are suggesting is chemically not possible"

As most of you know, TFTestkits uses Taylor chemistry almost exclusively. Their dependability and repeatability is synonymous with high quality. They pretty much set the standard for this forum although we are in no way related.

So, now what do we do? Can Taylor be at least partly incorrect? Of course, but so can we.

I implore each of you to keep one important aspect of this conversation in mind. I am opposed to wordiness and complications in our methods. If the average pool owner finds our advice over his head, he will simply ignore it.

Adding complexity and "in the weeds" detail to what we teach goes against TFP policy which is "Simplicity".........found on the home page, Caveats detract from that simplicity and blur the focus of what we are trying to teach.

I have often heard something like this opined within this forum, "Well, I don't think it's too hard to understand what were saying when we say "XXX XXX XXX"
I liken that to a neurosurgeon saying his profession is "not too hard". Well, yes it is if you don't know how to do it.

So, I would like to see this interesting information sort itself out over time. If we can prove it CONSISTENT, then the time will likely come to modify our advice, but I don't think that time is now.

 

[SoDel]

I spoke with Wayne Ivusich from Taylor Technologies yesterday. He has been with Taylor for eons. Many of you may have met him at trade shows. Wayne left NO wiggle room, "FC and CH are completely unrelated. What you (Dave) are suggesting is chemically not possible"

As most of you know, TFTestkits uses Taylor chemistry almost exclusively. Their dependability and repeatability is synonymous with high quality. They pretty much set the standard for this forum although we are in no way related.

So, now what do we do? Can Taylor be at least partly incorrect? Of course, but so can we.

I implore each of you to keep one important aspect of this conversation in mind. I am opposed to wordiness and complications in our methods. If the average pool owner finds our advice over his head, he will simply ignore it.

Adding complexity and "in the weeds" detail to what we teach goes against TFP policy which is "Simplicity".........found on the home page, Caveats detract from that simplicity and blur the focus of what we are trying to teach.

I have often heard something like this opined within this forum, "Well, I don't think it's too hard to understand what were saying when we say "XXX XXX XXX"
I liken that to a neurosurgeon saying his profession is "not too hard". Well, yes it is if you don't know how to do it.

So, I would like to see this interesting information sort itself out over time. If we can prove it CONSISTENT, then the time will likely come to modify our advice, but I don't think that time is now.

I agree with the simplicity aspect and of course a pool should never become a complex project for folks who just want to swim .

On the other hand, can we keep this thread as a “let’s try to find out what’s going on here” sort of a thing? Seems a bunch find it interesting and no action need be taken on whatever the result may be.

Your info from Taylor is super helpful and confirms what has been said many times — calcium has no effect on FC and you have added a very important piece — calcium also has no effect on our testing. So if (capital IF) there is an effect, it has to be something else. I’m very curious what it may be and given seemingly several anecdotal reports, we may be on to something.

 

[Bperry]

My thinking was to have measurable quantities in a bucket the people have at home. And ideally two of them. Anything around and below 1g will be difficult to weigh, and buckets around 10L are relatively common. No idea what is common on the other side of the Pacific.

Another thing is: We are thinking about impurities as a potential cause. How homogeneous are those impurities distributed in a bag of CaCl2? Probably don't want to go to microscopic for that reason.

Anything with an “L” as the measurement quantity is harder to come by.

 

[Bperry]

I had similar thoughts (great or maybe strange minds think alike lol) but I’ve already done the experiment in my pool (albeit, in a very uncontrolled way). Referring to my notes, on 6/10/22 FC 7.5, 6/11/22 FC 7.5, 6/13/22 FC 7.5, 6/14/22 FC 7.5 added 10 lb CaCl2, 6/15/22 FC 5.0 (all testing done around 0700 each day listed). My FC is always pretty steady, so the 2.5 ppm drop caught my attention, but at the time I don’t recall linking it to the CaCl2. Fast forward a while and I did see anecdotal reports that this sometimes happens but from the chemistry it should not happen. It was just seeing this thread that got me to thinking it must be some impurity, assuming it really can be attributed to the CaCl2 and not some other coincidence.

Unfortunately, the bag of the particular CaCl2 I used was “it” so I don’t have any more of exactly the same whatever it was to try again. I don’t remember what brand it was but picked it up at a local pool store and I remember it was $18 for a ten lb bag.

If the working theory is an impurity (seems it has to be) then we need a sample from someone who has experienced this phenomenon and has some more of the exact same stuff left.

But for the heck of it, I do have an unopened box of a different brand of CaCl2 I bought from Amazon to have on hand to get ready for winter, and if I get the chance later today I’ll try various additions in 5 gal pool water to see if anything happens from that. Why not?

Experiment that isn’t repeatable by the original party as well as others is pretty worthless. One off results likely point to some other factor. That’s why it would need to be controlled and repeatable.

 

[Lake Placid]

I think it’s all good even with a large rise in CH. I’ve been told by a couple of people who really seem to know what they’re talking about that CaCl2 absolutely does not affect FC. A large amount of whatever impurity is theorized to exist is good — should produce a result. If it does not, maybe that says something too.

In scanning my old notes, I also notice a slight FC increase the day after adding acid. It may have been you (or someone) who suggested maybe the SWG has something to do with all this calcium stuff because that also doesn’t make sense from the chemistry?

I do believe the statement from those much smarter than me that CH has no effect chemically on FC. But I can’t discount my own experience that I have witnessed on multiple occasions - a drop in FC when targeting a large adjustment in hardness rise.

This leads me to hypothesize that it must be impurities coming along for the ride with the calcium chloride that are responsible for the loss.

I have buckets and a scale and can make the time to satisfy my curiosity. I’ve wasted more time when I was younger on stupider endeavors.

 

[duraleigh]

SoDel,
Certainly, I would hope we keep this thread open as we continue exploring this issue.

My point is that we not "rush to judgement" and come up with modifications of our advice until this is further vetted. We could be on the cusp of a new discovery or perhaps we have consumed too many adult beverages for too many years. My cumulative total is becoming troublesome!

 

[MichaelT20]

Definitely agree with you Duraleigh - no need to change guidance or recommendations just yet.

That said - I’ll definitely be watching my fc every time I add Calcium.

I’m on team “probably impurities or additives to certain brands”.

I’m out of the hardness plus from Leslie’s that I used previously. I’ll try with a new batch from them sometime soonish (in the next week or 2) and see if a similar drop occurs and report back.

 

[duraleigh]

I’ll try with a new batch from them sometime soonish (in the next week or 2) and see if a similar drop occurs and report back.

Do you add calcium regularly?

 

[MichaelT20]

Do you add calcium regularly?

No but this is a new pool (2 months) and I’m a newbie . I’m still getting everything in balance. CH I’ve been a little slower to add because it was above minimum but not quite at recommended yet.

I’ve been doing things slowly as I learn

I’m also a little on the low end for cya but need to backwash this week so will do the cya after backwash.

 

[duraleigh]

There is a tendency for CH to actually increase in a new pool. Test once more just before you add.

 

[mgtfp]

And also test your fill water. Calcium added with fill water stays in the pool when water evaporates. Each time you replace evaporated water with calcium rich fill water, CH will rise a bit. Based on the first CH values on your log, I have the impression that your fill water CH my not be that low.

Depending on the amount of rain (causing overflow) and backwashing, CH may or may not rise over time.

Plus what duraleigh mentioned. Until the plaster in a pool is fully cured, it may release some calcium into the water.

 

[MichaelT20]

There is a tendency for CH to actually increase in a new pool. Test once more just before you add.

Thanks will do. I’ve been very slow about it - only adding once every week or 2.

 

[dfwnoob]

I spoke with Wayne Ivusich from Taylor Technologies yesterday.

Looks like you got to him just in time! According to their LinkedIn, he's retiring in September. I hope you have some more contacts over there!

 

[duraleigh]

Yeah, he has been around a long time and told me of his retirement. He is a good guy and a very accessible resource, but, you're right.......we need to find others.

 

[kyndacrazy]

I just experienced this as well after adding 25lbs of Robelle Calcium Hardness purchased from Amazon. My CH was at 240 and slowly dropping with refills due to evaporation. I wanted to get closer to 400. I check my levels near daily and run my FC on the lower side 3.5-4 with my SWCG set at 28% - it has been keeping my FC consistently dialed in with little fluctuation. My CYA was at 70. Tests were conducted just prior to adding the CH. After adding the 25lbs and running for 12 hours, FC tested at 2.0, after 24 hours FC was at 1.0. I cranked my SWCG up to 50% and ran for another 24 hours, FC is still only at 1.5. So I started googling the relation between CH and FC to no avail, then stumbled across this thread. Not trying to add unscientific points here, but anecdotally I cannot find an explanation as no other variables changed other than adding CH.

I’ll also just add that I’m using a Taylor FAS-DPD test kit.

Picture of CH I used attached.

 

[SoDel]

I just experienced this as well after adding 25lbs of Robelle Calcium Hardness purchased from Amazon. My CH was at 240 and slowly dropping with refills due to evaporation. I wanted to get closer to 400. I check my levels near daily and run my FC on the lower side 3.5-4 with my SWCG set at 28% - it has been keeping my FC consistently dialed in with little fluctuation. My CYA was at 70. Tests were conducted just prior to adding the CH. After adding the 25lbs and running for 12 hours, FC tested at 2.0, after 24 hours FC was at 1.0. I cranked my SWCG up to 50% and ran for another 24 hours, FC is still only at 1.5. So I started googling the relation between CH and FC to no avail, then stumbled across this thread. Not trying to add unscientific points here, but anecdotally I cannot find an explanation as no other variables changed other than adding CH.

Picture of CH I used attached.

Do you have any of it left? I’m not sure of an end game in this without, like, GCMS, but if the result can be repeated in a bucket, seems to narrow the funnel a bit anyway.

Just sort of spitballing but two potential issues come to mind. From a rabbit hole I jumped in not long ago it seems that most calcium chloride sourced in US comes from sea water. I think PoolStored posted an MSDS with what may be in it. Is it possible any of those things affect the fas/dpd test? Two, some calcium chloride is produced using ammonia. The ammonia is later extracted because it is valuable, but doesn’t seem far fetched that the extraction might be imperfect. May be interesting to test a sample of your stuff for ammonia. I’m sure there are many other ideas out there.

 

[Bperry]

I just experienced this as well after adding 25lbs of Robelle Calcium Hardness purchased from Amazon. My CH was at 240 and slowly dropping with refills due to evaporation. I wanted to get closer to 400. I check my levels near daily and run my FC on the lower side 3.5-4 with my SWCG set at 28% - it has been keeping my FC consistently dialed in with little fluctuation. My CYA was at 70. Tests were conducted just prior to adding the CH. After adding the 25lbs and running for 12 hours, FC tested at 2.0, after 24 hours FC was at 1.0. I cranked my SWCG up to 50% and ran for another 24 hours, FC is still only at 1.5. So I started googling the relation between CH and FC to no avail, then stumbled across this thread. Not trying to add unscientific points here, but anecdotally I cannot find an explanation as no other variables changed other than adding CH.

I’ll also just add that I’m using a Taylor FAS-DPD test kit.

Picture of CH I used attached.

If your calcium hardness was dropping, it wasn’t due to evaporation because the calcium stays in the pool and water is evaporated. Calcium hardness will increase overtime with evaporation.