Converting from Baquacil CDX to Chlorine

[ColaMan]

Greetings TFP Community! I’m new here but have been doing LOTS of reading to try and help prepare myself for the Baquacil to Chlorine conversion. Many thanks to everybody out there for all the great information shared within this forum! I’ve read the Convert from Baqua to Chlorine link several times, am familiarizing myself with Pool School and Pool Math, and have also been reading up on some experiences from several conversion threads. Last week I ordered the TF-100 test kit which should arrive within the next day or so.

As some background, we moved in 1.5 years ago and ‘inherited’ a Baquacil pool that used the CDX product. We had many struggles for most of the swimming season, but finally got the hang of it by the final month. Still, we realize there are more advantages of using Chlorine and are looking forward to making the conversion.

I’ve read that the CDX may extend the conversion process and am not necessarily looking forward to it, but I am ready to take on the challenge. Fortunately, when the pool was winterized in October 2016, almost half of the water was pumped out and now it’s filled to the top with water from snow/ice/rain (we have a mesh safety cover). So when I take the cover off in the next day or two, I’ll run the pump for a while to circulate the water before taking an initial reading using the Baquacil 4-way test strips. I’m HOPING the oxidizer and sanitizer levels have been diluted and are both LOW enough to immediately start the conversion process after adjusting for pH.

I read a little about percarbonates on some recent posts, but I am leaning towards not going down this route.

Unfortunately, I also did some conversion homework elsewhere before realizing this site was the best… therefore, I ended up with some non-Chlorine shock (aka Potassium Monopersulfate or Potassium Peroxymonosulfate) that I was planning on using when first opening the pool. Since I cannot return it (it actually wasn’t too expensive), will there be any disadvantages of using the package’s recommended amount as a first step before starting the initial bleach addition to 15ppm FC after ~24hrs? (maybe I will be able to use a few gal less of Bleach?) I don’t want it to be a waste of time, but thought it would help clean out any organic matter or Baquacil products that remain, similar to the purpose of 15 ppm FC.

I’ve found a decent price on 10% Sodium Hypochlorite pool chlorine/bleach at a local hardware store (Ace Hardware: 2.99/gal), so I plan to stock up there. Based on everybody’s experience, for a ~12500gal pool, does anybody have an idea on where I should start my initial stock? Maybe start with ~30gal?

I’m also thinking about separately cleaning/bleaching the ladder before installing it, as I’ve heard it can be difficult for the chemicals to circulate in all the ladder’s grooves to remove any traces of Baquacil. Do you think that’s worth a shot, or should I just throw it in from the get go?

Sorry if I missed any details… Please let me know if there are any questions or suggestions. Any support is greatly appreciated!

 

[JoyfulNoise]

Keep the MPS out of the pool for now. You can always use it later if you want. It won't help at all with the conversion process.

I'm not sure what your appetite is for experimenting but you might consider the percarbonate process. CDX is know to cause long conversions and chlorine only very slowly degrades the DMH. The success of percarbonate depends on getting the initial sanitizer level correctly determined which is often hard with strips. If the sanitizer level is low enough and your calcium hardness isn't too high, then percarbonate might short circuit a lot of the time spent on conversion. You're going to be paying for a lot of bleach either way.

Up to you. But the most important tool you need is a high quality test kit. I would've commend you get the TF-100 with XL option and the Speed Stir if you plan to go the percarbonate route. If you do the conversion with chlorine only, then either the TF-100XL or the Taylor K-2006C.

 

[ColaMan]

Hi Matt:

Thanks for the quick reply! Just opened the pool today and it looks pretty dirty (green/brown). I was able to prime the pump, skim some of the larger debris, and brush the sides and attempt to brush/push some of the settled sand toward the main drain before the sun set. I'll head out in the morning to vacuum and run the pump to help filter the water while I'm at work. Any recommendations on chemicals I could add in the morning? Or is it good just to filter to get the water as clean as possible? After filtering, I was planning to take a water sample to see where my Baqua Oxidizer and Sanitizer levels are at. If they're still high enough, I'd consider the percarbonate treatment - can Oxiclean be used?... or is it recommended to use the 99% pure sodium percarbonate?

Does anybody know why some recommend using the non-Chlorine shock and why it doesn't help with the conversion process?

Thanks for the recommendation for the XL option.. I only got the TF-100 - wish I would have added on the XL option when I ordered last week! At least it's good to know I should order some now so it's ready for later. Thanks again!

 

[JoyfulNoise]

Sorry, I wasn't very specific about the MPS. MPS is an oxidizer like percarbonate, the problem is, unlike percarbonate, MPS leaves sulfates behind after use. So, in general, they are not very well suited for use in pools simply because they add "stuff" to the water that you really don't need. Sulfates are a bigger problem for plaster pools or pools that use salt-water chlorine generators. Also, increased sulfate levels in a chlorine/water environment leads to more advanced pitting corrosion of steel hardware in a pool (rails, ladders, etc). Thus my recommendation to not really use it unless you have to.

If you wanted to attempt a percarbonate conversion, then you really want to use pure (99%+) sodium percarbonate, not OxyClean. OxyClean is only, at most, 50% sodium percarbonate. The rest is sodium carbonate (soda ash or washing soda) and fragrances or surfactants. You'd have to look around online for percarbonate in places like The Chemistry Store or Bulk Apothecary to see what the pricing is. It's not likely to save you anymore money than just going with bleach but it may save you time.

I would just get your equipment running and filter the pool, don't add any chemicals. Get the water as clean as you can (no need to worry about the green right away) and then get that sanitizer/oxidizer reading. A pH, TA and CH test would be excellent info as well since that will enable me to see how the percarbonate will affect pH and possible calcium scaling issues.

Don't turn on the heater if you can avoid it for now and let us know if you can bypass the heater at all.

 

[Flying Tivo]

Since you are on well water, you have the option to do a full drain and refill. This will almost feel like a fresh start but will still consume some additional chlorine.

Felipe

 

[JoyfulNoise]

Since you are on well water, you have the option to do a full drain and refill. This will almost feel like a fresh start but will still consume some additional chlorine.

Felipe

Can't drain an FG pool without bracing the shell and ensuring that the water table is far below the bottom of the shell or else the pool will pop out of the ground.

Tarp method is possible but not easy to do if the pool is free form.

 

[Flying Tivo]

Can't drain an FG pool without bracing the shell and ensuring that the water table is far below the bottom of the shell or else the pool will pop out of the ground.

Tarp method is possible but not easy to do if the pool is free form.

Thats right! Just read in-ground not fiberglass, sorry! Tarp method is doable just need assistance and a large tarp.

Felipe

 

[ColaMan]

Thanks for the added details regarding the MPS non-Chlorine shock. I can see it's not good for continued use, but I wonder if it would be OK to add it initially before starting the SLAM procedure with 15ppm FC? From what I've read, a pool of my size would need about 5-6lbs. Now my water is a medium-lighter shade of green after vacuuming in the am and running the filter all day. Do you think the MPS could help clear things up a bit before starting the addition of Chlorine?

As you can probably tell, I'm really anxious to get the process moving along. Unfortunately, I didn't read about the added time required for a CDX conversion and some warmer weather is right around the corner. I've already warned my wife that it's not going to be ready for 2-3 weeks or so and she's OK with it because she never liked the idea of Baquacil. I think I'm going to pass on the percarbonate treatment only because it's difficult to get the goods by tomorrow. So that's why I'm wondering if I should try the MPS as an oxidizer (instead of percarbonate)... or should I just dive into adding bleach? I'll be a bit bummed because I may not be able to see the water change colors if it's already green, but oh well

I got a quick/crude test using the Baq test strips and it shows the following:
- Oxidizer (Hydrogen Peroxide) is very low; recommends to add the initial start-up dose
- Sanitizer and Algistat is between 0-10ppm
- pH reads a little on the low side @ ~6.9-7.0 (maybe I can re-test using the TF-100 I just received today before increasing pH)
- TA ~ 80ppm
- on a side note, I noticed a couple back-swimmer bugs enjoying the pool

The water heater cannot be bypassed, but I'm definitely keeping it off until everything is converted and balanced. Thanks again to everybody for the support!

 

[JoyfulNoise]

If you're ready to start, then just follow the process and get a tanker truck of bleach backed up to your pool - Pool School - Convert Your Baqua Pool to Chlorine

Absolutely positively DO NOT raise your pH; there is no need. It is fine where it is and the bleach you will be adding will add enough excess lye to raise the pH a bit. Just get the bleach and go!

As for the MPS, do not use it. The one (of many) problem with MPS is that it interferes with the FC part of the DPD-FAS test. Adding MPS will make it appear as though your FC is higher than it is. Just don't add it, it's too little in quantity to make any difference and chlorine is a much more effective oxidizer than MPS. I know you want to use it because you bought it and can't return it but it has an extraordinarily long shelf life and so, someday, after a high 4th of July party where much beer was consumed and expelled into the pool, then you can use it...

With your sanitizer levels so low, hopefully the conversion will go quicker than most. Good Luck, take lots of pictures and keep us up to date on all the events...

PS - And no worries about not doing the percarbonate process. It's mainly for those that like to tinker and you've got other plans for your pool than using it as a giant chemistry set....

 

[ColaMan]

OK, I'll pick up at least 30gal of 10% bleach today and start adding it this evening. Is it OK to add the initial dose in the evening? Or should I start in the morning when I can check and add chemicals every hour to more frequently top up to 15ppm FC?

Thanks for the recommendations on pH and for the additional details about MPS non-Chlorine shock. I read some other threads on here where people were already using the MPS before they joined this forum and before they started the Chlorine addition, and it seemed like nobody really made much of a fuss about it. But again, I appreciate the information about the negatives of using MPS - and from what I understand, it's mostly used for getting rid of some of the Baq anyways, which are pretty low to begin with... so I'm excited to get right into the Chlorine addition!

Regarding the Chlorine addition, I'm hoping to clarify some points not listed on the conversion link:

1) Should the filter be placed into RECIRCULATE to avoid the sand in the filter from getting plugged up from the get go? Then collect and discard any foam or Baqua-goo with a skimmer net? If yes, when is it OK to put the filter back into FILTER mode?

2) Since we know a LOT of Chlorine will be consumed in the early phase of the conversion, does anybody have an idea of how often how much Bleach should be added (in the interest of saving time taking the FC reading and conserving the reagents). Ex: My initial dose to get to 15ppm FC from 0ppm is 240oz. Should I expect to add another 240oz in 1hr... or maybe 1 gal every hour or every other hour since the Bleach will be used up pretty quickly? I understand it may be a case by case basis depending on how much residual Baq is left in the pool, etc. But this will help if I can ask my wife to tend to the Chlorine addition while I'm at work, as I don't think she's up for learning how to use the TF-100 anytime soon

3) Somewhat related to 2) above, but are there any risks of adding a little too much Chlorine/Bleach to get the FC up near 20+ppm or more even though we know it will be used up eventually? Ex: bad on equipment or the pool surfaces? I've seen others reporting FC levels above 15, but maybe this was by accident...


Sorry if these questions were asked in other threads, but I appreciate any info and tips that can be provided. I'll definitely take lots of pictures along the way to share!

 

[JoyfulNoise]

1) Should the filter be placed into RECIRCULATE to avoid the sand in the filter from getting plugged up from the get go? Then collect and discard any foam or Baqua-goo with a skimmer net? If yes, when is it OK to put the filter back into FILTER mode?

Yes, initially I would just keep it in recirculate and not filter. Scoop out the Baqua-goop using your skimmer net and add a polypropylene hair net (https://www.amazon.com/Disposable-Hair-Spun-Bonded-Polypropylene-White/dp/B002XK2FS0/ref=sr_1_2?ie=UTF8&qid=1497028357&sr=8-2&keywords=polypropylene%2Bhair%2Bnet&th=1) to the skimmer basket. This will catch A LOT of goop and need to be changed very frequently.

Turn off the pump late in the evening, after your last chlorine addition + 30mins to circulate, and see what settles. Then vacuum (SLOWLY at low speed) the gunk off the bottom to waste.

Getting as much of the baqua-goop OUT of the water and not stuck in the filter will be a huge help. You still are going to have to change your filter sand, but the conversion should go a little faster.

2) Since we know a LOT of Chlorine will be consumed in the early phase of the conversion, does anybody have an idea of how often how much Bleach should be added (in the interest of saving time taking the FC reading and conserving the reagents). Ex: My initial dose to get to 15ppm FC from 0ppm is 240oz. Should I expect to add another 240oz in 1hr... or maybe 1 gal every hour or every other hour since the Bleach will be used up pretty quickly? I understand it may be a case by case basis depending on how much residual Baq is left in the pool, etc. But this will help if I can ask my wife to tend to the Chlorine addition while I'm at work, as I don't think she's up for learning how to use the TF-100 anytime soon

At first, the minute you add chlorine, it will be consumed by the baquacil. Add the chlorine, brush vigorously to mix and then wait 10 mins. I bet when you test the water there will be zero FC. You need to keep adding FC until it holds. Its going to be A LOT OF BLEACH at first.

3) Somewhat related to 2) above, but are there any risks of adding a little too much Chlorine/Bleach to get the FC up near 20+ppm or more even though we know it will be used up eventually? Ex: bad on equipment or the pool surfaces? I've seen others reporting FC levels above 15, but maybe this was by accident...

Yes, you can accidentally bleach your liner. You have no CYA in the pool water (which is intentional at this point) so the chlorine is completely unbuffered. 15ppm FC with zero CYA would be excessively harsh to swim in and would bleach swimsuits and hair. Stick as closely to 15ppm as you can and don't worry too much if it goes up a little higher. Temporary excursions are ok, holding the FC at 20ppm for days on end is not.

 

[ColaMan]

Turn off the pump late in the evening, after your last chlorine addition + 30mins to circulate, and see what settles. Then vacuum (SLOWLY at low speed) the gunk off the bottom to waste.

Great tips! Should I turn the pump off in the evening as you mentioned and leave it off overnight to vacuum settled Baqua-goop ONLY during the noticeable goop phase? Or turn it off every night during the conversion phase? Or once the amount of goop is reduced, change over to FILTER mode and keep the pump/motor running all night for the OCLT?

At first, the minute you add chlorine, it will be consumed by the baquacil. Add the chlorine, brush vigorously to mix and then wait 10 mins. I bet when you test the water there will be zero FC. You need to keep adding FC until it holds. Its going to be A LOT OF BLEACH at first.

I agree, I can imagine it will probably consume a lot of Chlorine on the first day or two... does anybody have an idea what an average amount of Chlorine that should be added in one day... especially the first day? Ex: 2gal at first... wait 10mins as you mentioned then add 1 gal... wait maybe wait another 30mins and add another 1gal, etc.? I'm not worried about bleaching my liner, since I have a white fiberglass pool (is it possible to bleach a white fiberglass liner?), and I'm definitely not planning on swimming in it till this is all said and done... would there still be some other negative side affects to dipping above the 15~20ppm mark during the conversion period? Again, I'm just trying to avoid a little bit of time and supplies with FC testing, especially during the first day or two when we know it'll be requiring a LOT of Chlorine... I just don't have an idea of what others have experienced during their first couple days of the conversion. Don't get me wrong, I'm not going to go crazy and dump all 30gal in on day 1, but I am wondering if staying on the higher side will help speed up the conversion. Thanks again!

 

[JoyfulNoise]

I would only turn off the pump overnight when you're in the thick of baqua-goop production...so most likely just the first few days. After that, if the water is clouded with fine enough suspended solids it's unlikely they'll settle overnight and then filtration is really needed.

There is no simple answer to chlorine loss. Some people experience having to add 20 gallon in the first few days with nothing holding and others seem to get a chlorine reading to hold right away. It all depends and that's why you need testing in order to care for a pool - only testing will tell you what's going on.

As for higher levels of chlorine, one thing you can learn later about chlorine chemistry is that the loss rate of chlorine to UV light exposure is proportional to the concentration of hypochlorite in the water. And so a pool with 20ppm FC will lose chlorine at a faster rate than 15ppm. In the beginning of your baquacil conversion, chlorine loss is going to be dominated by the biguanide oxidation. Later on, when the water is still cloudy, the UV loss component will start to increase and eventually be the dominant form of chlorine loss during the daylight hours. So even if all of the biguanide is oxidized and removed, unbuffered FC in a pool (that is, a pool with zero CYA) has a half life of about 20mins or so. Thus, in less than a few hours, 95% of the chlorine is destroy by UV oxidation. By adding more chlorine (say 20ppm instead of 15ppm) you're only wasting it and spending more money that you have to. This is why in a clean and clear swimming pool one needs cyanuric acid (CYA) stabilizer - it protects the chlorine against UV loss.

Just stick with 15ppm for now as we know it works fast enough without being a huge waste of money.

 

[ColaMan]

The Conversion is officially underway and we're getting some good colors, as you can see in the pics below!


Today BEFORE adding bleach:



Today AFTER adding first 2 gal of 10% bleach:

I would only turn off the pump overnight when you're in the thick of baqua-goop production...so most likely just the first few days. After that, if the water is clouded with fine enough suspended solids it's unlikely they'll settle overnight and then filtration is really needed.

So far I'm not seeing any goop after about 3 total gal added, but I'll check it out in the morning.

As for higher levels of chlorine, one thing you can learn later about chlorine chemistry is that the loss rate of chlorine to UV light exposure is proportional to the concentration of hypochlorite in the water. And so a pool with 20ppm FC will lose chlorine at a faster rate than 15ppm. In the beginning of your baquacil conversion, chlorine loss is going to be dominated by the biguanide oxidation. Later on, when the water is still cloudy, the UV loss component will start to increase and eventually be the dominant form of chlorine loss during the daylight hours. So even if all of the biguanide is oxidized and removed, unbuffered FC in a pool (that is, a pool with zero CYA) has a half life of about 20mins or so. Thus, in less than a few hours, 95% of the chlorine is destroy by UV oxidation. By adding more chlorine (say 20ppm instead of 15ppm) you're only wasting it and spending more money that you have to. This is why in a clean and clear swimming pool one needs cyanuric acid (CYA) stabilizer - it protects the chlorine against UV loss.

Thanks for the Chemistry lesson, I really appreciate all this information... I definitely have MUCH to learn. Based on the fact that a majority of the chlorine can be destroyed by UV oxidation, should I focus on adding chlorine overnight help get rid of the Baquacil... especially in the first few days? If it's a really sunny day, should I avoid adding during peak sun and limit it to the morning, evening, and later at night? If necessary, I'm willing to set an alarm to add bleach to the pool every couple hours throughout the night if it'll mean clearing up the pool quicker and converting to Chlorine quicker. Thanks again!!

 

[JoyfulNoise]

Nice lime green Kool-Aid you have there

No goop is a good sign but it can show up along the way. Just skim anything solid you can from the surface.

As for chlorine loss, just aim to keep it near 15ppm as best you can, day and night. Where this all really comes into play is later on when you're nearing the end of the conversion and you're trying to see how much chlorine you're losing to "organics". AT that point, you want to measure your chlorine loss overnight as then there is no interaction with UV light. During the day, you'll still lose a lot to sunlight.

If one were truly trying to avoid UV loss, then you could cover the pool. Problem is, the conversion process creates lots of combine chlorine compounds (chloramines, etc) that can only leave the water through outgassing (at least, that's the way you want them to leave). So covering a pool to try to protect the chlorine starts to become counter-productive as CCs will build up with no where to go. There is also some benefit to chlorine loss from UV - the creation of chlorine and hydroxyl radicals. When chlorine is exposed to UV light, one chemical pathway for the chlorine to degrade is through the creation of free radicals (both chlorine radicals and hydroxyl radicals). Those free radicals are INCREDIBLY powerful but short-lived oxidizers. So, even when chlorine is being expending by interacting with UV, some good can come of it.

Just keep adding bleach.....that's why I made reference to having the tanker truck of clorox nearby

 

[JoyfulNoise]

Any updates?

 

[farmerpatti]

I'm just completing my conversion of a 27,000 gallon pool that used CDX. For two straight days I tested every 2 hours and upped the chlorine. I had 12.5% and we went through about 50 gallons in 3 days. The pool looked like a total loss with all the stuff floating and accumulating in the middle. We vacuumed it with the hose (not vacuum attachment) for 2 1/2 hours backwashing every 10 minutes. We had fuzzy type 'stuff' on the sides that cleared up well with a couple of brushings. Fun Fun. After that initial 2-3 days of goo and ugliness it became crystal clear, then we tested the pool after dark, added to get to FC15 then tested in am ... we would then wait to add chlorine until dark again, after we tested again. It did take us longer to get through it, (I'm guessing at least only putting in at night the chlorine was 'available' to do it's thing against the Baqucil - so we might have used less chlorine) but we were gone over Memorial weekend and then got back at it --- just vacuuming and brushing regularly. We are 2 1/2 weeks in, but could have done it faster probably by dosing for a few more days after the baqucil goo was pulled out.

We put our steps in after I bleached it down several times, and didn't see any problems with it. A few days later we reached our 1ppm max loss overnight.

Don't get discouraged ... take pictures...wish I had.

I just cleaned my sand (we put new sand in at the beginning of this season) and it looked like brand new.

Good luck

 

[ColaMan]

Thanks again for the recommendations and for checking in! I kept adding Chlorine every 1-2hrs today, topping up near 15ppm FC per your recommendation, even in the sunny warm near 90's (air temp) weather today. In total, between yesterday evening and today, we have gone through almost 14gal of 10% so far. It's still looking like Lemon Lime Gatorade, but I think it's looking a little better than it did after the first Chlorine addition.

Luckily there was still no goop today, so halfway through the day I turned the flow valve to FILTER and still have not noticed goop. In addition to the Gatorade color, the water is also pretty cloudy - definitely can't see the bottom of the pool... does this go along with the process? I have had to add some well water several days ago and have not used any metal treatment chemicals... should I worry about metal/iron removal now or after the OCLT has passed and it's time to balance? Does this Lime color normally last for the first few days?

I think I might be near my attachment limit, so I'll post one pic taken at Mid-day today in the sun:

 

[ColaMan]

farmerpatti: great job on your successful conversion!! Thank you for taking the time to help out a fellow 'converter'! You have a lot of great tips that I will definitely follow and keep in mind. It's good to know from your experience that your water became crystal clear after about 2-3 days of the ugliness... I'm at the 1.5day mark and can't wait for things to clear up!

 

[pookiesunshine]

ColaMan, cant help you with the metals aspect, but when i converted my pool last year, i had a lot of goo on the bottom of the pool as well as some floaters. So keep an eye out down there. Definitely vacuum that to waste when/if you see any.