how often to SHOCK ?

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i think the test kit should be modified somewhat:
if its an indoor pool with no sun, no dirty air (filtered air as is in some aquatic centres), a clean pool deck, low or no bather loads, yeah you could keep FC's down to IDEAL recommended levels ( 1.5 to 2 ppm as its depicted on the kits).
The big mistake is ' its physically impossible to do that for an outdoor pool ( that would be my mistake) to keep those levels (FC"S) low like that.
its, as mentioned, pretty much, a feel for what you see the pool door ' outdoors'. if there is alot of wind or dirt or rain, or a lot of sun with not enough CYA then yeah it would become a sudden problem .
the end result is that you would have to increase the FC's to a level that doesnt seem to cause cloudy water ( factoring in of course the CYA levels from the pool calculator).
 
Forget the 1.5 to 2 ppm FC or any other FC amount recommended on standard test kits. They do not understand the chlorine/CYA relationship. You should be following the Chlorine / CYA Chart in the Pool School. Also, if you don't have enough CYA in the water then in an outdoor pool the FC will drop too quickly from breakdown from sunlight. Usually an outdoor pool needs at least 30 ppm CYA, some need 50 ppm CYA, and in very hot sunny areas even more may be needed to minimize chlorine loss, though it gets risky at higher CYA levels IF one lets the FC get too low.

As for the "ideal" FC levels mentioned on test kits, even in low bather load pools with no blown-in dirt, those levels will still not be enough unless the CYA level is quite low because algae will be able to grow faster than chlorine can kill it. It is the FC/CYA ratio that is important. Forget about the absolute FC level by itself. You need enough CYA to lessen the loss of FC from sunlight and then at the CYA level this determines the minimum FC you need at all times so you normally shoot for a higher level to start with so that you end up at or above the minimum the next time you dose with chlorine.

If you have a lot of water dilution, you can get away with using some Trichlor tabs and then supplement with chlorinating liquid -- it is very rare to be able to use Trichlor tabs alone since usually there isn't enough water dilution to keep the CYA from climbing too quickly.
 
Those indoor pools you refer to with 1 to 3 FC recommended USUALLY don't have any cya in them because it isn't required. 3 FC with NO CYA is fairly potent and you can liken that level to an FC of say 6 to 8 with cya at 40 to 50 in an outdoor pool.
 
woodyp said:
Those indoor pools you refer to with 1 to 3 FC recommended USUALLY don't have any cya in them because it isn't required. 3 FC with NO CYA is fairly potent and you can liken that level to an FC of say 6 to 8 with cya at 40 to 50 in an outdoor pool.
Click to expand...

It is actually worse than that. See the chart here: http://richardfalk.home.comcast.net/~ri ... l/HOCl.htm

With 0 CYA and a FC of 2ppm, the active chlorine level is around 1ppm
With CYA only 30ppm, to have the same active chlorine level would be a FC over 20ppm
With 30ppm CYA, and our recommended FC level of ~4ppm, the active chlorine level is 0.06ppm ... that is 16 times lower than the unstabilized pool ... and thus 16 times LESS HARSH.

This is why we recommend CYA in even indoor pools. Not for the protection from the sun, but for the chlorine buffering effect.
 
3 days into slamming, the water is slowly getting back to clear..Im not worried about that.
When the slamming is over, instead of sticking with the 1.5 to 2 as the 'ideal' cL level, i think i will take the advise of the TFP monitors.
-i will keep the level just high enough so that the clarity is kept...of course, factoring the CYA from the pool calculator.
i guess the only way to prevent the pool from wobbling out of control ( foggy water) is to watch it twice a day.
the pool light at night really does a good job as any signs of cloudiness looks like fog around a car headlight...
any suggestions or tips to add in ???
 
Clarity is secondary, sanitary is your primary goal. Keep the FC correct to keep the pool sanitary and algae free, and clarity will happen.

But use the formulas. Don't base your FC on whether or not the water is clear.
 
I agree on that.. i think what happened is that my CYA being really low at 7 ppm and the sun being 80 degrees straight up ( where at the 22 degree latitude). And wind continuously blowing dust into the pool ( you can see it on the surface of the water). The Cl cant keep up with the dirt demand.
i'll have to raise the CYA to 30 ~ 50 as per pool calculator and raise the FC's just to make sure the chlorine can oxidize the stuff being blown in
 

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hypothetically, if the sun never shined over the pool, could i get away with 1.5 or 2 ppm @ 0 CYA levels for an outdoor pool?
as in the pool calculator, the higher the CYA levels are the higher the FC's have to be and,
too little a CYA with the sun suddenly directly above all of the FC's dipping below 1.5 can spell disaster, is that right?
 
Answers in Red below.

dolphin said:
hypothetically, if the sun never shined over the pool, could i get away with 1.5 or 2 ppm @ 0 CYA levels for an outdoor pool?

Yes. BUT ... the active chlorine level will be very harsh resulting in dry skin, frizzy hair, and faded swim suits. It is much more comfortable to be in a pool with 30ppm CYA and 3-4ppm of FC.

as in the pool calculator, the higher the CYA levels are the higher the FC's have to be and,
too little a CYA with the sun suddenly directly above all of the FC's dipping below 1.5 can spell disaster, is that right?

Yes. The CYA protects the FC from the sun. With 0 CYA, you will lose 50% of the FC every hour with the high sun. And thus the FC will quickly drop too low and be gone and let stuff start growing. With higher CYA levels, the required FC level is higher ... BUT ... you do not loose as much to the sun so the amount of chlorine you have to ADD to the pool each day is actually LESS than if you had lower CYA.

For you I would recommend taking the CYA up to around 50ppm and then keeping the FC above 4ppm at all times. Every day boost the FC up to around 7ppm and by the next day it should still be above 4ppm and then boost back to 7ppm.
Click to expand...
 
yeah i like that idea..i was looking for a recipe like that... going with your method what i'll do i'll increase the Trichlor erosiion amount so that the ppm is a 4 or 5 untill the CYA settles in at 50 . boost the FC level back up to 7 just after sun stops casting over the pool.
i'll loose more FC's until the CYA reaches its level of 50 but to compensate, i'll make more Triclor erode even more .
is that somewhat of a recipe?
 
what i find problematic, is that most test kits ( the quick test kits ) only test around the ideal mark ( which is ok for the most part or an indoor pool) if i use the fas DPD kit it can get pretty expensive conducting several test daily.
with the cheap kit i mentioned, i usually gestimate the intensity of the color beyond the bright yellow ( around 3 ppm max with these kits ).
above that, a thin brown layer develops, that tells me the FC level is above 4.
i use that Pentair Cl on one side and the pH on the other side ( a palm sized kit ) the one where you just add 5 drops to either cylinders
 
i will shoot for the numbers you just mentioned.. ill have to take a reading just before the sun hits, then in the middle or peak sun altitude, and finally at test right after the last rays of sun shines on the pool - to see what the cause and effects are or to adjust the recipe or dosage
 
Once you get a feel for the usage, you should only have to test once a day (ideally late afternoon / early evening), then use that result in PoolMath to tell you how much bleach to add to get back to the target. Then you should be fine till the next evening.

The FAS-DPD test is the only one that gives you accurate results. But you may eventually get good enough to make sure the test stays a deep yellow and just use the FAS-DPD a little less often.

Like I said before, once the CYA is in the water the chlorine is greatly buffered, so even if you got the FC higher than intended, no one would know and it would still be less intense than with no CYA.
 
yeah thats essentially - exactly what i had to do; compare the 2 FAS DPD kit alongside the simple cheaper test kit and familiar with the level of yellow.
Basically, the error here was letting the FC's get too low this then eventually led to cloudy water and some algae settling on the steps.
Fortunatly, a simple sweeping and vacuuming and brushing made short order of that.
The Slamming also made quick work on that as well.
Its the 3 rd day and the water is almost clear, you have to look pretty hard to see the fogginess of the water.
my old brush, the bristles were so brittle that they kept breaking off into the pool, so the lack of brushing also led to the situation.
The moment i started slamming i had to go out and buy a new brush. pool surfaces really do look great!
This time, when i'm done with the brush, i give it a rinse and soak it in a bucket with backing soda hoping itll keep the bristles from becoming brittle.
Next week Monday, if the Slamming is over, ill shoot some numbers and we can compare notes if you like
 
The SLAM levels for chlorine are not high enough to degrade the brush and baking soda will not change anything. Sitting in the sun will cause more damage than any of the chemical concentrations.
 

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