Please Help / Advise

[prh129]

The text below is from "Water Chemistry for Swimming Pools" that is linked in one of the threads in the "using chlorine" section. My understanding is that shocking = superchlorinating and if you succesfully shock then CC should go to 0. From the text below, it says to do that FC needs to be 10x of CC which would be 70 ppm in your case which sounds way too high. I don't have the experience to suggest what you should do so I won't.

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Breakpoint Chlorination is the process by which combined chlorine and some organics are "burned out" of the pool by addition of large amounts of chlorine. The reaction of chlorine with ammonia to form chloramines occurs in several stages with free chlorine consumed at each stage. If enough chlorine is added to the water the total chlorine residual will rise to a point that forces the reaction of chlorine with ammonia to go rapidly to completion. Compounds of nitrogen and chlorine are released from the water and the apparent residual chlorine decreases. The point at which the chlorine residual suddenly drops is called the breakpoint. When enough chlorine is added to pass the breakpoint, combined chlorine compounds disappear, eye irritation potential and chlorine odors disappear, and the chlorine remaining in the water is all in the free state.
Superchlorination: In order to prevent buildup of chloramines in the pool it is necessary to periodically add large amounts of new chlorine in an effort to pass the breakpoint. Public swimming pools should be supechlorinated about once a week. The amount of chlorine needed to reach the breakpoint will vary depending on the amount of organic material introduced by bathers and on the level of free chlorine maintained in the pool. If the amount of combined chlorine is known then the amount of new chlorine needed is ten times the amount of combined chlorine. When combined chlorine residual is not known, superchlorination is accomplished by adding 10 ppm of new chlorine to the pool. Ordinarily calcium hypochlorite at a dose of at least 1 lb. per 10,000 gallons is used for superchlorination. The chart below shows the amounts of various chlorine compounds which can be used to introduce 10 ppm of chlorine to the pool.
Chart No. 9 - Superchlorination
(Amount Needed to Introduce 10 ppm)
Type of chlorine GALLONS IN POOL
15,000 20,000 25, 000 50,000
Sodium Hypo 1 1/4 gal. 1 2/3 gal. 2 gal. 4 gal.
Lithium Hypo 3 1/2 lbs. 4 3/4 lbs. 6 lbs. 12 lbs
Dichlor 2 lbs. 2 2/3 lbs. 3 1/3 lbs. 6 3/4 lbs.
Calcium Hypo 2 lbs. 2 1/2 lbs. 3 1/4 lbs. 6 1/2 lbs.

[meajma]

Thanks for that prh, it's clear that I have much to learn. I'll take it slow and will try to get my FC up, I'll probably need to wait until I get my new kit as the readings seem suspect to a few folks here.

Thanks again,

Mark

[meajma]

So here's what I did last night..

I recorded my readings in a previous note.. the FC was only at 5 and I had a CC reading of 7. Yikes..

So, I took the Tri-Chlor pucks out of my feeder and rinsed everything out very well..

I purchased two 5 gal barrels of 12.5% sodium hypochlorite.

I poured ~ 1 gal directly into the skimmer, and then poured ~2.5 more gallons around the perimeter of the pool. I swashed it all around and waited ~ 1 hour.

Took another FC reading and had to put in 30 drops to make it turn clear.. so that made sense to me.. I had raised my FC up to ~15ppm.

BUT.. all those drops depleted my R0871 solution..so I can't test again until I get my 234 kit.

When I went to get the liquid chlorine last night at Naamco, I saw a cheapo test kit although the scale for chlorine only went up to 3 ppm, and even though it only cost $5, I didn't bother getting it.

Anyway, thanks alot for all your help. The pool looked pretty much the same this morning.. not bad at all, just still a little cloudy in the 8' end.

[DavidD]

Bummer on the R0871. Hate to stop now so If it were me, Id got back to the pool store with a sample and let them test. Be sure to take the sample directly there and keep it in the shade. If they sell Taylor chemicals, you may get lucky (extremely lucky) and they have R0871. It appears you have the "biofilm" problem Ben mentioned (see Waterbears post above). Problem is, without a good test method and 0 CYA and no way to test I don't know exactly how to advise. You must keep the FC between 10 and 15 in order to beat this. Yo Yoing won't do anything but feed the bio and cost you money. You are going to be using up chlorine FAST with the "bio" and the UV. You should probably buy the chepo kit if you can't get R0871 and use "Carl's patented shot glass method" of testing which is basically diluting the samples with distilled water to make a tester that was intended to test up to 5ppm to test higher. Use a 1 part pool water to 3 parts distilled water and see what happens. If the test reads 4 you have 16ppm. Only problem is that most of these only test for TC and cannot determine FC or CC which is really what you need. Hope the pool store is close....

[meajma]

Yeah, bummer...

But, I just called another local pool store and they do free testing so I'll at least be able to get some results until my 234 arrives. I'm sure that they'll also try to sell me everything in their store but that's the way it goes when ye let things slide..

I'll keep the FC up there and post any progress or questions.. speaking of questions..

IF I keep the FC up there.. what am I expected to see.. ? Will it be that my CC decreases until it gets to 0.5 or somewhere around there..?

Anything else that I should notice or pay close attention to..?

Thanks again ya'll !

Mark

[aylad]

With a vinyl liner and 0 CYA, if you'll just up your chlorine to 12-15 ppm, re-test and add whatever amount is necessary to come back up to the 12-15 level 2-3 times daily, keep your pump running, then you should start to see your cc coming down. When it comes down to zero, then let your cl drift back down and add your CYA.

You can use trichlor pucks in your feeder if you add your liquid chlorine into the pool itself instead of the skimmer---once it's mixed with water, then you shouldn't have a problem. I add my bleach into the return stream with my feeder running on a regular basis.

Janet