Since everyone here (including me it turns out) seems to enjoy Baquacil conversion threads, here's mine:
After having swam in my parents' pool recently, I noticed that it was not quite as nice as I remembered from my childhood. The pool was originally a chlorine pool and was always crystal clear, and even for a few years after converting to Baquacil it stayed quite nice. Baquacil was expensive but really did reduce the amount of maintenance, at least to start. But eventually the problems set in.
They've been having the typical Baquacil problems: hazy water (could barely see the bottom of the deep end), flaky white water mold, and a few algae breakouts a year they need to treat, not to mention the extreme drain on the finances. In addition, the water since the move to Baquacil has always been very foamy and tastes disgusting, which upon reading more here I suspect might be due to the algaecide. (Does anybody know if the Baquacil algaecide is a linear quat?)
It's an in-ground vinyl pool, 32' by 16', of 15,500 gallons. (Amusing aside: The pool store had it estimated at 25,000 gallons! And they recently recommended they add 40 pounds of calcium increaser to raise their CH from about 60! [Remember, vinyl pool.] Fortunately that never happened.) It has a Hayward Perflex EC65 DE filter, with one skimmer, one return, and no main drain.
I mentioned this site to my Dad, who being an engineer and kind of sick of not having control over the pool (not to mention spending money!), was also interested. Unfortunately the level of sanitizer in the pool was quite high; probably a little over 50 ppm, but it was hard to tell on the Baquacil test strips.
In a strange twist of fate, there was also about a 1 foot section of the liner bead that had fallen out of the slot a couple of seasons ago that they had been unable to fix yet. We figured that by lowering the water 8-10" and pouring hot water on the exposed liner below the gap we might be able to get the liner to (CAREFULLY) stretch enough to get back into the slot. As a bonus, refilling the water would dilute the Baquacil to about 40 ppm. Then we could start converting the pool.
So, this morning I headed out to buy a lot of bleach. I got 40 gallons of 10% bleach ("Liquid Shock") from Rural King for $10 per box of 4 (on sale). This was within spitting distance of the best bleach price I found ($1.09 for 3 quarts of 6% at Aldi's), but I figured the 10% concentration and packaging convenience was worth it for the amount necessary for a Baqua conversion.
I lugged all the bleach to their house (and a gallon of muriatic acid) and we started to vacuum the pool to waste. Once the water level was down far enough, we successfully reinstalled the liner bead, threw some garden hoses into the pool, and went to get lunch.
We removed the ladders as some have recommended for Baqua conversions. These will be cleaned separately and reinserted once the pool is stable.
Once the water level was back up and the filter running and refilled with DE, we lowered the pH from 7.5 to around 7.2 with muriatic acid, putting in just shy of the amount recommended by the pool calculator.
A pH recheck in half an hour seemed to indicate success, so there was nothing left to do but start pouring in bleach, 2.3 jugs at a time. I have to say that the immediate and striking plume of green that started circling the pool was well worth the price of admission for this endeavor; that was very cool!
The first dose was at 1:00 PM. The pool looked pretty well mixed by 1:15 (the color change was handy for that), and a chlorine test with both OTO and crappy test strips showed that the chlorine we poured in was already gone. Checking with Baquacil strips for giggles showed a Baqua level of around 30 ppm. Another 2.3 gallons...
At 1:45, FC from the strips was empty again, though the OTO test was starting to show a higher TC. Baqua level was somewhere around 10-15 ppm. Another 2.3 gallons...
Checking around 2:30 showed a Baqua level of zero, and chlorine left over! Wasn't expecting that so quickly. Topped it up as best we could with the crappy estimate from the test strip. At this point chlorine started going down much slower, and we kept it topped up throughout the day, brushing occasionally to clean and mix.
I was expecting all sorts of trouble from the DE filter, but it really hasn't been. The pressure is certainly going up, but we're not having to clean it every hour or anything. I think the pressure started at 11 PSI, and it had raised to 19 by 7:00 PM. Bumping reduced it to 13 PSI, and it was up to 16 by the time I left. We'll probably replace the DE tomorrow morning. I was worried it would have to be cleaned ever hour. We got some nylon knee-highs to use as crude skimmer socks, and a lot of the Baquagoo seems to swirl around in the skimmer where it can be lifted out, so maybe not much of it is making it to the filter. Anyway, not complaining...
The TF-100 XL kit should be here tomorrow, just in time to start overnight FC testing.
All in all, I'm amazed at how smoothly and quickly the first stage of this process has gone. Hopefully the water will clear up and hold FC in a few more days.
Thanks to everyone here for this site and community. The explanations here, especially of the CYA/FC issue, really make sense. Even when on chlorine, pool maintenance was always a little mysterious, but I think the information and people here really make it not anymore.
I'll try to remember to post updates on the conversion progress, and of course will chime with any questions that arise.
Finally, I know people are otherwise going to complain that This Thread Is Worthless Without Pics, so enjoy: