Pool Chemistry suggestion

outbacktommy

Well-known member
May 11, 2017
55
Elk River, MN
Pool School is perfect, almost. It would be helpful if, along with the recommended chems and levels, there were some basic guidelines as to HOW to add each of the various chemicals. One sentence is enough. Disperse directly into the pool? Pour in front of return? Should it go in the skimmer basket? Avoid the skimmer basket? Pre-dissolve in a bucket of water- how big of bucket, how much water, max amount of chem to add to the bucket, etc? I noticed that even on the label of pool products, instructions on how to add it are frequently missing- when you are using non-pool chemicals, clearly there are no relevant instructions. I'm clear that "somewhere" in the forums there are instructions, but I think they should be at the "top of the page" along with the other basic information.

I also noted that the pool calculator has goals for all chems except for salt and borates. Could these be added, please? I love this calculator and use it all the time.

One last suggestion: I learned this year that CYA degrades over time. Most information implies that you add it once and the only way to lower it is to replace water. I'm going to guess that there are other chems that persist, but not indefinitely (sequestrants?). Is there a table that would provide an estimate of the half-life of these more persistent chemicals. If my CYA was high and I knew that CYA was likely to deplete itself by x amount in a month, then I might choose to wait it out rather than go through the wasteful effort of draining a bunch of water, replacing it, then rebalancing it. I'd add this as a sticky post or edit the relevant Pool School section. This is 'Trouble-Free' Pool after all, not OCD Pool :)
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,952
NW Ohio
If my CYA was high and I knew that CYA was likely to deplete itself by x amount in a month, then I might choose to wait it out rather than go through the wasteful effort of draining a bunch of water, replacing it, then rebalancing it. I'd add this as a sticky post or edit the relevant Pool School section. This is 'Trouble-Free' Pool after all, not OCD Pool :)
You actually illustrated exactly why we don't go in to the weeds of CYA degradation with new people, because sometimes a person gets the idea that they can just wait for the problem to go away. CYA degrades at a rate of less than 5 ppm per month in a pool with adequate chlorination and at typical temperatures. Heat and extremely high chlorine can speed the break down, which is why it can actually be noticeable in a spa, but in a pool it degrades so slowly that it is within the margin of error of the CYA test month to month. If someone needs to "go through the wasteful effort of draining a bunch of water", then their CYA level is well more than 5 ppm over what is recommended. Suggesting that our advice should be "well just wait and maybe the problem will go away" doesn't sound Trouble Free to me.

Simplicity is the name of the game. We don't hide the truth, but we simplify the advice because a new person is already confused and doesn't need half-life charts thrown at them. (Not that such a chart would be very useful anyway since there are numerous variables involved that are not the same for every chemical. But I digress.) So we say CYA doesn't go away, which is true enough for the here and now. If someone has a CYA of 100 it isn't going to change any time this year and telling them anything other than "you need to replace your water" is not helping them correct their problem.
 

mguzzy

Well-known member
Jul 8, 2015
796
OV, CA
Here is a spin on that suggestion... Why don't we make a section that HAS all the hard core chemistry for those that follow it. There are a number of people on the forum that I know would. I would like to see someplace that has links or the actual peer reviewed science articles that support the TFP method (You quote this method is supported by science, then where is the citation). Half life charts of the chems, Stoichometry of the chemical reactions.. It would be an area for the science geeks. I find these gems here and there. Like someone just posted a PDF with the Stoichometry that shows how much CL is in a Jug of 12.5% chlorine. It would be nice to have them collected into one spot. A forum thread that is a sticky might suffice.
 

outbacktommy

Well-known member
May 11, 2017
55
Elk River, MN
Sounds like I might have struck a nerve with some- sorry about that.

To be specific, I had CYA last season of 60 in my Minnesota in-ground pool. I do not drain anything for winter (to preserve the integrity of the auto-cover). This spring, I had issues that required some more intensive care and thought that my CYA was still at 60- based on my assumptions and extrapolation of bits of disconnected information presented here. It had completely depleted over the winter months and was 0. I did not test the CYA as I had exhausted my CYA testing reagents last year tweaking it to 60 and thought that no further attention to it was required. Yes, it was up to me to test and get it right, but I arrived at the wrong conclusion based on incomplete data. I'm not upset, I just wish I knew more at the time. One sentence indicating that CYA degrades slowly over time would have done the trick, and it was just my luck that I did not stumble upon such in my browsing.

Anyway, kudos to you all. TFP and its contributors ROCK!
 
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Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,952
NW Ohio
What you experienced wasn't even chlorine breaking down like that, it was more likely an ammonia conversion that continued through the nitrogen cycle. Pretty typical, actually.

I'm just going to leave this quote from the Pool School article on opening your winterized pool (link) right here:
Chlorine levels would be at zero, however initial TA, PH, and CYA levels must be determined prior to adding chemicals to balance pool.