Using BBB Method for my First Year as Pool Owner - Going Great - I think?

[harshja]

August will complete my first year owning my new house w/ my first pool. When I overtook the pool maintenance duties, this is the first place I came for everything - because I literally knew nothing.

Firstly, the pool specs:

• In-ground concrete pool, about 15 years old.
• Seems to have been pretty well maintained, though some repair work was obviously done on the tiles & some of the lining.
• Since no specs were given to me, and utilizing my skills as a Mechanical Engineer, I think I have properly estimated my pool volume @ 10,000 gal. - almost exactly. I drew up a CAD layout to calculate head loss on the pipes too because that's what we engineers do for fun (and to figure out if my 2 HP pump was way overkill, which I think it is, but separate issue).
• Lots of direct sunlight throughout the day, some shade in the morning, a bit more in the later evening. With evaporation, I find that I have to refill w/ my faucet probably 45-60 mins per week. Not sure what that flow rate would be, but everyone has an outdoor faucet so it's kind of like that.
• I backwash after heavy rains with debris, after pool parties, or spontaneously when it has been a while - probably twice a month on average. I have a DE filter.

Immediately the BBB Method caught my eye & I began buying bleach in bulk @ Home Depot, along with Muriatic Acid. Target had a clearance on their 4 lb. boxes of Baking Soda so you can bet I bought out their shelf. I threw some boxes of Borax into my cart too.

Also to preface, my first purchase after reading through the site was the FAS-DPD test kit from Taylor (K-2006). It has worked really well, and I have purchased a few replacement bottles of reagents as needed from TFTestkits - sometimes ordering their proprietary version, or sometimes the Taylor genuine depending on their availability.

My questions after 1 year of experience:

1. Is it ok (giving me accurate results) that I have partially substituted the genuine Taylor reagents for the TFT equivalents?
2. I measure chlorine & pH levels every 1-2 days, especially now in the summer (I live in Dallas where it's generally 100+ highs & 80+ lows this time of year). I find that I have to add 64 oz. of 8.25% bleach probably 2-3 times per week to maintain an average of 3-5 ppm Cl. And this is with tested CYA levels that are actually off the charts (we'll get to that later) @ about 110 ppm. It seems the CYA would decrease the breakdown of Cl much more than this, despite the negative consequences of high CYA values. Why does the Chlorine break down so quickly?
3. I believe the previous owners exclusively used Trichlor tabs to chlorinate - for years - without ever completely draining the pool, and this could account for the high CYA values. Over the fall/winter I added no Trichlor, only bleach, backwashing regularly and achieved a CYA level of about 30-40 at my lowest point. My mistake here was that I tried to obtain a 50ppm saturation by re-introducing Trichlor tablets. This completely made my job easier as far as addition of bleach, as it maintained a constant 5 ppm with basically no work for several weeks at a time. However, I tested my CYA levels a month later and found them back up to 110 ppm or more. How should I correct this mistake? It seems that if I drain the pool at this point and restart @ 30 ppm CYA or so, then my bleach would just break down even faster - maybe resulting in addition of 64 oz. every day?
4. With all of the addition of bleach, and with it being a basic compound, I find my pH levels off the chart almost as frequently as I test the chlorine - usually 8.0+ after 2-3 days. Usually the test requires about 4 drops of acid reagent to bring the pH down to reasonable levels of 7.2-7.4. With alkalinity always coming in about perfect @ 80-100 ppm, why is my pH so wacky?
5. Borax? Yeah right - I have NEVER had to touch that box sitting on the shelf. Do people actually experience low pH values? Because I have yet to experience this whatsoever. It's constantly up, up, up w/ the pH. The method needs to be renamed to BB+MA for me (MA = muriatic acid). Am I doing something wrong here?

I have plenty more questions, but mostly they concern equipment. I figure this is a nice wordy post to get me kicked off on the right foot again. All help is very appreciated!

[chem geek]

1. By TFT do you mean the reagents in the TFTestkits TF-100 or similar test kit? Those ARE Taylor reagents, just repackaged, so you can use them if they are the same number. The only one that won't translate over is the reagent for the pH test since the TF-100 uses a K-1000 Taylor kit for the pH test and that uses the R-0014 while the K-2006 kit's pH test uses the R-0004. Even though they are both phenol red indicator dyes, their concentration is different since they are intended for use with different volumes of water sample.

2. 64 fluid ounces of 8.25% bleach in 10,000 gallons is 4.2 ppm FC which 2-3 times per week would be 1.2 to 1.8 ppm FC per day which with a 3-5 ppm FC level is 24% to 60% loss. A typical pool with FC/CYA levels high enough to prevent algae growth usually loses around 2 ppm FC per day so you are less than that probably due to your CYA level. It is possible that you have some nascent algae growth that is not yet visible (i.e. isn't yet clouding up the water) due to your FC being too low for your CYA level (or conversely, your CYA level being too high). However, your CYA measurement may be wrong. After mixing the pool water sample and CYA reagent for 30 seconds, do you hold the view tube in front of you with your back to the sun for strong indirect lighting?

3. For every 10 ppm FC added by Trichlor, it also increases CYA by 6 ppm. So with 2 ppm FC per day chlorine usage, that would increase CYA by 36 ppm per month. I'm not sure how your CYA jumped from 30-40 all the way to 110 using just Trichlor in just one month. Are you sure you weren't adding Dichlor as well at some point? Perhaps your CYA test reading is incorrect.

4. Your TA is not perfect. When using a hypochlorite source of chlorine such as chlorinating liquid, bleach, Cal-Hypo or lithium hypochlorite, you need to have the TA be lower because the pH will rise from carbon dioxide outgassing in the pool. Though the hypochlorite chlorine has a high pH, you are forgetting that chlorine usage/consumption is an acidic process with the net result being pH neutral except for a small amount of excess lye. You may have aeration sources that exacerbate the outgassing such as waterfalls, spillovers, fountains, etc.

5. Did you think that BBB meant you had to actually buy and use bleach, borax and baking soda? That is not what BBB means. It is a system for understanding what is going on with your pool by using a good test kit and only adding the minimum of what you need. The components of BBB are simply an illustration of grocery store equivalents for some common pool store chemicals -- they are not what you have to use in your pool. For most pools using the BBB system, they only add chlorinating liquid or bleach and some Muriatic Acid.