Slow Release Chlorine

[EskimoPie]

I have a couple of buddies who firmly embody the idea that "you can lead a horse to water...". We all got pools at about the same time but I had found TFP during the construction phase and quickly told the builder to switch from a Frog system to a SWCG. Both of my buddies stuck with the Frog. They are tired of paying the money for the refill chlorine packs but are completely unwilling to switch to BBB or to another method.

What they want to do is simply re-fill the frog chlorine packs with pucks and just use the frog as an in-line chlorinator. They are discussing on what sort of pucks to put in... one insists that there are "slow release chlorine" pucks v.s. ones that dissolve faster. He's concerned that the faster dissolving pucks will cause problems when the pump isn't running and it creates a strong acid solution.

From what I understand, the only 2 types of pucks are either TriChlor or DiChlor. I know they both have CYA and I'm under the impression that it's the CYA that enable the slow dissolving. I heard somewhere that TriChlor has a higher chlorine content (which I'm assuming must mean a lower CYA content) so DiChlor would actually be the slower dissolving puck. Is that right?

I've explained to them the hazards of increasing CYA yet they just don't seem concerned... they seem content with draining and refilling their pools every couple of years and dumping in bags of shock regularly.

All of our pools are less than a year old so they haven't had any significant issues yet, but I'm going to have a hard time containing my 'I TOLD YOU SO!' after theirs turn green some fine summer day and I'm still swimming in a sparkling blue pool. In the mean time, I'd like to at least give them some correct information on the pucks. Anybody care to enlighten me?

 

[JasonLion]

Almost all pucks are made of trichlor, dissolve equally slowly, and contain CYA. Occasionally you can find some pucks made out of cal-hypo, which dissolve much more quickly, contain calcium, and do not contain CYA. Most cal-hypo pucks are wrapped in plastic, as a way of slowing down the rate at which they dissolve. The Frog comes with trichlor in it's packs.

 

[EskimoPie]

Found this (from ChemGeek) which I'll definately show them and jives with what I was thinking:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by 7 ppm.

Which dissolves the slowest? And is it really a significant difference? I'm guessing it's not. When they originally insited on getting frog systems they said the frog didn't have this problem because it drained when the pump wasn't running, but they've said that sometimes opening the frog with the pump off they find it partially full of water so they are still dissolving the pucks.

 

[EskimoPie]

Almost all pucks are made of trichlor, dissolve equally slowly, and contain CYA. Occasionally you can find some pucks made out of cal-hypo, which dissolve much more quickly, contains calcium, and does not contain CYA. Most cal-hypo pucks are wrapped in plastic, as a way of slowing down the rate at which they dissolve. The Frog comes with trichlor in it's packs.

Thanks, Are the cal-hypo pucks/sticks acidic like the tri/dichlor is?

 

[duraleigh]

EP,

Give them the web address and let it go. This forum and the old PF are strewn with unsuccesfull attempts to convert relatives and friends who don't want to convert.

Likewise for someone who is willing to let you take care of their pool but doesn't have enough interest to log on and learn even the basics.

As I've said many times, "No good deed goes unpunished".

Disclaimer......There are always a few exceptions (very few) to what I said above. However, your situation doesn't sound like one of them.

 

[frustratedpoolmom]

Okay, They talked about putting in new tabs, which frankly I don't see how they can get them in the canister, but maybe I'm just not understanding it. Also, the pacs are held in place by the mineral cartridge. Are they still planning to use the mineral cartridges at $99 a pop every six months? I don't see how they can continue to properly work the pacs, refilled or not, without the mineral cartridge in place.

Let them read this, from 2006 on the Pool Forum. AS a former Frog owner, it was a big eye opener and explained alot. Year one eh? I developed problems with the frog around end of season two, beginning of season three and it was all down hill from there....

Just my .02....

http://www.poolforum.com/pf2/showthread.php?t=98

 

[chem geek]

Thanks, Are the cal-hypo pucks/sticks acidic like the tri/dichlor is?

Trichlor is very acidic and is normally sold as pucks/tablets or sticks though sometimes it is ground and sold as powder/granules. It is very acidic. It also increases CYA. Trichlor in pucks/tablets dissolves very slowly -- usually taking 5 days for a puck to dissolve in a floating feeder and a couple of days or so to dissolve in a chlorinator or in the skimmer (only for Trichlor designed to go into the skimmer, such as BioGuard Smart Sticks) depending on flow rates and pump time.

Dichlor, to my knowledge, is only sold as powder/granules and never as pucks/tablets. It is moderately acidic, when accounting for chlorine usage (i.e. it's not acidic upon addition, but chlorine usage is acidic). It adds more to CYA, for the same amount of chlorine, as Trichlor does. It dissolves very quickly.

Cal-Hypo is not acidic and essentially has the same effect on pH as adding bleach or chlorinating liquid (or lithium hypochlorite, for that matter). The pH rises when you add it, then it drops when the chlorine gets used up so is essentially pH neutral. It does, however, add to Calcium Hardness. Cal-Hypo is usually in powder/granules and dissolves reasonably fast, but not as fast as Dichlor so is best to pre-dissolve in a bucket of water. It also comes in pucks that dissolve faster than Trichlor though they tend to fall apart near the end and also tend to leave a gummy residue of the binder that is used to hold the pucks together.

Richard