Adding BBB

[Water_man]

I haven't found a sticky regarding how to add BBB and in what order.
It makes sense that bleach should be broadcasted but what about Borax and baking soda? Through skimmer or broadcasted. Also, suppose everything has to be adjusted
during spring opening, what is the order of chemical addition, including TA, CH and shock?

[waterbear]

I haven't found a sticky regarding how to add BBB and in what order.
It makes sense that bleach should be broadcasted but what about Borax and baking soda? Through skimmer or broadcasted.
Into the skimmer is fine. Make sure the pump is running.

Also, suppose everything has to be adjusted
during spring opening, what is the order of chemical addition, including TA, CH and shock?
It really depends on what the numbers are. but generally adjust TA and pH first and then adjust CH. Also, shock is a verb, not a noun. That means it's something you do to a pool, not a specific product. Any of the unstabilized chlorines are suitable for shocking--sodium hypochlorite (bleach), calcium hypochlorite (what is commonly sold as 'shock' in 1 lb bags--will cause calcium hardness to rise), lithium hypochlorite (THE most expensive form of chlorine you can buy). I would not recommend using dichlor for shocking on a regular basis (also sold as shock sometimes) because it will cause your CYA levels to rise very quickly and can lead to an overstabilized pool with it's associated problems of algae outbreaks, cloudy water, and, in worst case, black spot algae or white water mold and pink slime (pink algae).

If you could post a full set of test results for FC, CC, TC, pH, TA, CH, and CYA it would give us information so we can give you better advice as to which needs to be adjusted first. Sometimes the very first adjustment is to either add CYA if it is below 30 ppm or to start a cycle of partial drain and refills if the CYA is too high and the pool is overstabilzied (usually over 50 ppm is too high for a manually chlorinated pool but slightly higher levels are managable if adjustments to your FC and shock levels of chlorine are made.)

Hope this is helpful.

[Water_man]

Hope this is helpful.

Thank you, Waterbear. Until being "re-educated" by this forum I used stabilized trichlor tablets for maintaining 3 ppm chlorine and calcium hypo to shock (2 to 3 lbs.) I intend to use my remaining stock of tablets until they run out, and to shock with bleach. Soon the pool will be reopened and I'll have all the numbers. BTW, I assume that most pool owners, including bewbees, understand that "shock" is a verb. I assume you and others who remind this to us mean that just adding FC won't shock, if not done right and with the proper amount. "Ben's Best Guess CYA chart" determines the amount of free chlorine neeeded to shock a pool as a function of the CYA level. I found other publications that determine the amount of needed FC by simply multiplying the CC by 10, regardless of the level of CYA.
Here's one of these links, provided by Indiana State Health Dept http://www.in.gov/isdh/regsvcs/sanen...pool_shock.htm

Why do they ignore the CYA level and why Ben's chart doesn't use the 10 X CC rule to calculate the FC needed to shock? I'm sure that CYA and CC levels are totally independent and it seems that both chemical species should be considered when it comes to calculate the FC needed to shock.

[chem geek]

Why do they ignore the CYA level and why Ben's chart doesn't use the 10 X CC rule to calculate the FC needed to shock? I'm sure that CYA and CC levels are totally independent and it seems that both chemical species should be considered when it comes to calculate the FC needed to shock.

There are many possible answers as to "why" but that really doesn't matter. The chlorine/CYA relationship in terms of the equilibrium chemistry, and specifically the fact that the FC/CYA ratio roughly determines the amount of disinfecting chlorine (hypochlorous acid), was definitively determined in a scientific paper written and presented at a symposium in 1973 and published in 1974. That's nearly 35 years ago. By comparison, the dangers of smoking were first known in the 1950's and only more fully acknowledged by that industry in the 1990's, a period of roughly 40 years. Perhaps there's pride in trying to break a world record here.

But even ignoring that chlorine/CYA relationship, one can also ask why the following basic rules are not taught by APSP Tech or NSPF CPO:

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 CH by 7 ppm.

Those are chemical facts independent of concentration so should be easy "rules-of-thumb" taught in courses, wouldn't you think? A little simple math assuming just 1 ppm FC per day using Trichlor tabs/pucks means that CYA would climb by over 100 ppm in 6 months, ignoring dilution (from splash-out, backwashing, etc.).

As for shocking, Ben's chart is referring to a shock level used to clear algae at a reasonable rate. Though it can also be used to more rapidly clear Combined Chlorine (CC), most outdoor pools exposed to sunlight and properly maintained with sufficient FC relative to CYA simply don't get much measurable CC. Technically speaking, even the 10x rule for CC is inaccurate. The chemistry behind the 10x is for the amount of chlorine (in ppm FC which is a "chlorine gas" equivalent) needed to oxidize an amount of ammonia (in ppm Nitrogen) and comes from an actual stoichiometric (ppm-based) amount of 7.6 that becomes more optimal in the range of 8-10. However, for CC (which is measured as chlorine, not ammonia-nitrogen), you technically only need half of the CC amount in FC to "break" it (assuming the CC is monochloramine). The extra chlorine for shocking to get rid of CC just makes it go faster, but in a properly managed pool the disinfecting chlorine is continually breaking down ammonia/urea from bather sweat and you do not need to shock.

There are many myths in the industry and I'm slowly putting together something of a training program that I hope will correct or augment current training (see this post), but this will take time and the industry has so far not been receptive to change. I don't give up, however, because there's something about truth that drives persistence.

Richard

[waterbear]

Chemgeek basically said it all. I really have nothing to add.

[Water_man]

If I maintain my FC according to the "Ben's Best Guess CYA chart" (my current CYA reading at opening is 56) and suppose I don't have algae, do I still need to shock on a weekly basis? Is the need to shock determined by the level of CC? If yes, what's the upper limit of CC ?

[chem geek]

If you don't have algae (or unusually high chlorine demand or water turning dull or cloudy) and you have <= 0.5 ppm CC, then you don't need to shock. Even if you have some CC that's a little above 0.5 ppm, you could wait a while and see if a sunny day plus some time takes care of it. Usually this would happen after a heavier bather load -- you could shock if you wanted to, but could just wait a day or two instead.

Sometimes if I get a suntan lotion film on the water and am impatient at getting rid of it, I'll shock or use a non-chlorine shock. I use the the latter if my wife is swimming every day and doesn't want to be in at higher chlorine levels. This situation is rare -- I've only done it once and usually I just let the film be as it does clear up if she doesn't keep adding to it every day.

Richard

[waterbear]

(my current CYA reading at opening is 56) and suppose I don't have algae, do I still need to shock on a weekly basis? Is the need to shock determined by the level of CC? If yes, what's the upper limit of CC ?

How are you testing? Most CYA tests do not have the resolution to give a reading like 56 ppm. Even the $1000 colorimeter/turbidity meter we use at work is +10/-25 ppm for the CYA test.

[Water_man]

How are you testing? Most CYA tests do not have the resolution to give a reading like 56 ppm. Even the $1000 colorimeter/turbidity meter we use at work is +10/-25 ppm for the CYA test.

The colorimeter at the pool supplies store.
My Taylor kit is due any day now. Does it have a better res?

[waterbear]

Are thet usuing a colorimeter with either liquid reagents or dry reagents in a vial or are they using a strip reader with test strips?