Adding BBB

[Water_man]

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?

The store tech pipetted the water samples into sealed rectangular shaped vials that must have contained reagents (I'm not sure if they were liquid or dry) and then she took the reading off the colorimeter.

[Water_man]

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

Thank you, Richard. Unfortunately, I haven't found yet on the board a sticky that deals with these questions.
Here's are some further questions:
1. Suppose the CC is > 0.5 and there's no algae condition. Do I still need to use the "Ben's Table" , or should I use the 10x CC rule? I'm asking because with my CYA level of 56 , the 20 ppm FC level off the Table seems high. How long would it take for the FC to dissipiate and thus enabling a safe for swimming level of FC?

2. If CYA is stable, as I've read here, and since it protects FC from UV, then how come it is still mentioned here in many places that one should shock in the evening, otherwise the FC will be quickly destroyed by the Sun's UV?

3. I'm sure that no such thing as "average bather load" is accurately defined, and that other bio-enviromental factors are involved, but, what frequency can I expect of FC addition in order to mainatin my normal FC level? Is it daily, or twice a week, or what?

4. What's the best thing to do when one goes on a 1- 2 week vacation and the pool is left unattended?
Shock before you leave? Add trichlor tablets?

Please let me know if a FAQ answering all these questions and other, related ones is posted here or elsewhere. If not, I'm sure it would be very helpful and would save a lot of time and bandwidth.

[waterbear]

The store tech pipetted the water samples into sealed rectangular shaped vials that must have contained reagents (I'm not sure if they were liquid or dry) and then she took the reading off the colorimeter.

Ok, That would be a LaMotte Waterlink or Waterlink Express. It's a pretty good system. We use the same at work. I will warn you that the TA test often reads low and so does the calcium hardness. It has to do with the limitations of the meter so if your Taylor test reads higher on these believe it.

[Water_man]

My Taylor kit is supposed to arrive any day now.
Is the test's chem based on titration? Does it offer an accurate reading?

[waterbear]

My Taylor kit is supposed to arrive any day now.
Is the test's chem based on titration? Does it offer an accurate reading?

which Taylor kit did you get? Hiopefully you got a K-2006 and not a K-2005.

[Water_man]

which Taylor kit did you get? Hiopefully you got a K-2006 and not a K-2005.

K-2006. I'm a quick learner

[chem geek]

My responses below in bold.

1. Suppose the CC is > 0.5 and there's no algae condition. Do I still need to use the "Ben's Table" , or should I use the 10x CC rule? I'm asking because with my CYA level of 56 , the 20 ppm FC level off the Table seems high. How long would it take for the FC to dissipiate and thus enabling a safe for swimming level of FC?

If the CC is only a little high -- say 1 ppm or so -- then I'd just wait for the next day to see if sunlight helps get rid of it along with time from exposure to normal chlorine levels. If it's really high, then that's unusual and a shock level could be tried, but it could be persistent chlorine that virtually nothing but dilution will get rid of -- that's rare except in some indoor pools. I don't think the 10x rule is useful for CC, period.

2. If CYA is stable, as I've read here, and since it protects FC from UV, then how come it is still mentioned here in many places that one should shock in the evening, otherwise the FC will be quickly destroyed by the Sun's UV?

Quickly is a relative term. You are right that it isn't so quick and you can shock in the morning if you want to, but if sunlight cuts down chlorine over the day by, say, a third, then a third of a high FC shock-level number is quite a lot. If you shock at night, then you get the entire night at that high level compared to the daytime where only part of the day is at that high level and some of the day is at a lower level. It's not a huge deal -- just an optimization.

3. I'm sure that no such thing as "average bather load" is accurately defined, and that other bio-enviromental factors are involved, but, what frequency can I expect of FC addition in order to mainatin my normal FC level? Is it daily, or twice a week, or what?

That depends on the CYA level since sunlight is the biggest factor, generally more so than bather load unless you've got many people using the pool (not just 1-3). Dupont defines high bather load at < 1000 gal/bather/day, medium bather load at 1000-5000 gal/bather/day, and low bather load at >5000 gal/bather/day. This assumes some unknown amount of time, probably between 30 minutes and an hour of a bather in the water "per day". For manual dosing, one usually needs to add chlorine every day or two depending on CYA level and sunlight exposure. With a pool cover, one can usually add chlorine twice a week (that's my situation).

4. What's the best thing to do when one goes on a 1- 2 week vacation and the pool is left unattended?
Shock before you leave? Add trichlor tablets?

You can automate "liquid" chlorine dosing by using The Liquidator talked about in this thread which may last 2 weeks if there's no bather load. Otherwise, you either need to get someone to add the chlorine manually or you can use Trichlor tabs/pucks, but even with tabs/pucks the chlorine will likely only last about a week or week and a half -- probably not 2 weeks. Also, Trichlor is very acidic so you'll want to start out with the pH a bit higher. You can shock and after the chlorine drops some (over one day), then add a full dose of PolyQuat 60 algaecide similar to what is done on closing. Probably the best thing (other than having someone add chlorine) is having a pool cover that is opaque to sunlight as that can cut down the chlorine usage to 0.5 ppm per day or so.

Please let me know if a FAQ answering all these questions and other, related ones is posted here or elsewhere. If not, I'm sure it would be very helpful and would save a lot of time and bandwidth.

I don't think this info is in one place that I can find, but it is in various posts.

Hope that helps.

Richard

[Water_man]

My responses below in bold.



Hope that helps.

Richard

Thank you again, Richard, for this detailed response.
I understand that it's beyond the scope of this part of the forum, but I'd be interested to see the chemical details of the correlation between CYA level and the amount of FC needed to shock. You mentioned before a paper presented long time ago. Has anything been published so far on line?

Also, it's not easy to understand why such a high level of FC is needed to break 0.5 - 1 ppm CC in an alagae-free shock treatment. In my case it's 19.8 FC (CYA =50), taken from the table you posted at troublefreepools.com. Is it because of the fact that in the presence of CYA, "free" HOCl doesn't exist, but it's rather bound to CYA?
If we need to move on to the China Shop for this purpose, please let me know.

[chem geek]

Continuing in the China Shop in this thread.

[Water_man]

Hope this is helpful.

Got my Taylor k-2006 kit today! Impressive and worth the price! (got it from SPS -Swimming Pool Supply Company -good price and prompt shipping).
The pool (actually the "swamp") was opened last Friday.
Now it's sparkling blue, after performing the "usual" green pool routine (*) and lots of POPP.

Here are the numbers:

CYA 60
FC 7.5
CC < 0.5
TA 140
pH 7.9
CH 170

I followed your advice and started to take care of the pH and alkalinity. Since I have in stock "dry acid" I added half the calculated amount needed to bring it to pH 7.6.
I used 1 lb. One thing I learned here - slow down with adding chemicals!
I wonder where can I get muriatic acid. Home Depot doesn't carry it. Hydrochloric Acid (the actual compound) is cheap - I wonder if chemical supply houses sell it to residential end users.

(*) the "green pool routine" I used : shocked to 20 ppm first day and on day three, frequent backwashes, brushing, vacuuming, floc, robot cleaner.

It goes without saying that with 60 ppm CYA this pool won't see chlor tabs any more!

Any other suggestions?