yellowish spots on bottom of the pool

[chem geek]

Chlorine breaks PolyQuat down into smaller pieces, at first more quickly and then more slowly. The smaller pieces are still effective at inhibiting algae, but eventually they will also either break down or get caught in the filter since they do act as a clarifier. From my own experience with Trichlor pucks and use of PolyQuat years ago, I would say that in warm pools it stays at reasonably protective strength for about a week. I only dosed every other week and still got algae, though the FC was 3 ppm and the CYA was 150 ppm when that happened. Had I dosed every week, the CYA could have gone higher. So the level of protection drops over time. Just remember that it isn't designed to completely prevent algae growth when there is no chlorine in the water -- it's a supplemental algaecide to chlorine, though it will significantly slow down such growth.

Now with colder water, it will break down much more slowly which is why it can be useful when closing a pool in the winter, though it still may not last for the entire closure.

 

[JamesW]

(and within 4 days hopefully my FC will be 0 and i can do the stain removal).

Using citric acid to lower your chlorine will minimize the amount of time that your chlorine is below 7.5 % of your Cyanuric acid level. You can do the stain removal without waiting for your chlorine to drop by using an extra 2 pounds of citric acid.

The entire process can usually be done overnight. At the end of the day, add the citric acid, and by morning you should be ready to begin bringing your chlorine back up if all of the stains are gone..

 

[michmike]

hi chem geek, may i ask why you followed this dosing with poly every 2 weeks? i assume now that poly increases CYA. at 150 cya, your chlorine is innective, right? from what i read such high levels are dangerous.

 

[chem geek]

hi chem geek, may i ask why you followed this dosing with poly every 2 weeks? i assume now that poly increases CYA. at 150 cya, your chlorine is innective, right? from what i read such high levels are dangerous.

The increasing CYA came from my use of Trichlor tabs/pucks in a floating feeder, not from the use of PolyQuat. I started out with 30 ppm CYA and had a low chlorine demand of 0.7 ppm FC per day due to the mostly opaque electric pool cover and less frequent pool use. After 11 months (1-1/2 7-month swim seasons) the CYA was 30+0.7*11*30*0.61 = 171 ppm which with some splash-out/carry-out, some chlorine oxidation of CYA, and one filter cleaning was 150 ppm. You can see how use of stabilized chlorine can build CYA up quickly if one does not have significant water dilution. That first year, I didn't put the rain water from the cover into the pool; I put it into the sewer instead so had no water dilution from rain in the pool.

I dosed every other week because I thought that with a cartridge filter (so no backwashing) that I would lose less PolyQuat from dilution so wouldn't need to add as much. As for the higher CYA level, it's not "dangerous", but it does reduce the active chlorine level which is what allowed algae to grow faster in my pool than chlorine and PolyQuat could kill it. Had I dosed with PolyQuat weekly as per the instructions, then maybe the CYA would have gotten to 250-300 ppm before algae would have grown.

 

[michmike]

hey guys one more quick question. the pool store also had jack's magic the magenta stuff. it is supposed to work with SWG and work as well as the purple stuff + it does not add phosphates. do you recommend that one then? would it work as well as the purple stuff?

have a great weekend all

 

[JasonLion]

Jack's Magic has a number of really good products, however I don't have enough experience nor heard enough about the magenta stuff to say how good it is. Most places magenta costs a bit more than purple, so I just go with purple which is proven to work really well. Phosphates are really not an issue at all, so there is no reason not to go with purple.

 

[michmike]

at my pool store they were the same price Jason. thanks!

 

[chem geek]

Jack's Magic® The Magenta Stuff® is Acrylic Acid Copolymer (probably with Acrylimide as the other monomer). This is really a flocculant more than a metal sequestrant. It prevents staining mostly by precipitating any metal oxides that may form rather than by sequestering the metal ions themselves. It will not be as effective a metal sequestrant as HEDP and the only reason I can see that it is used is the fear of "phosphates", though HEDP might be somewhat less strong as a metal sequestrant at higher salt levels.

 

[JamesW]

Jack's Magic® The Magenta Stuff® is Acrylic Acid Copolymer (probably with Acrylimide as the other monomer).

Is it the same thing as, or similar to, the sodium polyacrylate in the regular Clorox?

 

[michmike]

thanks chem greek. i am returning the magenta stuff to get the purple stuff instead. pool store salesman convinced me

 

[chem geek]

One of the copolymers is acrylic acid which is the acid of the conjugate base acrylate in sodium acrylate so is the same once in water at a given pH. Acrylic acid is acidic (pK_a is 4.35) so this will be in the acrylate form and is an anionic (negatively charged) polymer so will attract positively charged ions including metal ions but also calcium and magnesium. It isn't particularly selective in that regard so it is a mild metal sequestrant, but also a scale inhibitor. HEDP is a type of metal sequestrant known as a chelating agent and is much more selective to iron (especially) and copper and binds more strongly (see this post for some more info). Note that you NEVER want to add a cationic polymer such as PolyQuat or a linear quat to the water when using The Magenta Stuff or else you will get a precipitated cloudy mess.

Jack's Magic® The Magenta Stuff® also says it has Phos-Stop Plus which reduces phosphate levels so perhaps it also contains a some lanthanum chloride in it though that is not listed in the MSDS. It's 100% Proprietary Formulation that contains polyacrylic acid copolymer so there are other ingredients. Phosphate removers often cloud the water so having that clarifier/floculant in the product will help clear such cloudiness.

If The Magenta Stuff were superior to HEDP, then Jack's Magic would only need to offer it as the sole solution for metal stains. They don't do that because it isn't better and it's really offered to counter the objections to phosphate-based products. I would characterize The Magenta Stuff more as a phosphate reducer with a clarifier that inhibits scale and metal staining, not as an optimized strong metal sequestrant. However, in this thread note the following that was written:

Spoke with their tech staff and they stated yes the Magenta Stuff does contain as sequestrant mixed with copolymer but they said the ingedients are secret. I asked if it would be better to use the Purple or Magenta stuff, they said the Magenta if I have both scale and metal stains. If metal issues only the Purple Stuff.
:
The "Pink Stuff", he said is affected by chlorine, so best not to use in our cases and the Magenta is OK in both SWG and Non-SWG pools, as is the Purple, Blue in non-SWG pools only.
:
Question: Which is better for a SWG pool, "The Magenta Stuff or The Purple Stuff"?
Answer: For most pools he likes "The Magenta Stuff", and even the "The Magenta Stuff" for non-SWG pools with scale issues. He feels that unless the Iron problem is really serious, such as with fill water supplies, it is the best overall solution. But if metals are a big problem, or your pool is perfectly balanced and has no scale then "The Purple Stuff" for SWG or "The Blue Stuff" for non-SWG pools.
:
Question: Why does "The Magenta Stuff" cloud the pool when you pour it in?
Answer: It clouds when there are Phosphates present as it has Phosphate remover in it.

 

[michmike]

this is awesome info. i tried to find the incredients when i was at the pool store, but their stuff is "secret" and was not on the label. i was looking to see if it said HEDP anywhere.

 

[michmike]

I turned off my SWG last tuesday and now still my FC is at 4-5. wow. this CYA is doing its job. CYA is at 60 right now. I got to wait a few more days for FC to drop to 0 or go buy more citric or AA.

cheers.