Need help with Shock Process

Aug 26, 2012
28
Liberty, Tx.
First let me say this is a great site! I have been reading for days and have learned a lot but feel I am as lost as day one. We left our Intex pool (20’ x 4’) alone all winter long and now it’s all green. We started by renting a pump and draining all the water except for about 3” of water (hose could not get the rest). Then we filled it back up and added a box of “green to blue” from Wal-Mart. That turned it from green to gray. We tested the water and everything was way off. We added 7lbs of ph minus and it lowered it down to 8.0. So we added another 7lbs and now it’s down to 7.5. Then we added 5lbs of shock to get the chlorine up with no luck. That’s when I started reading on this forum and entered my readings into the pool calculator.
TH=200
FC=0
pH=7.5
TA=80
CYA=0
I printed the page of everything it says but I think I need to kill the algae. Water is still a milky color. So I read defeating algae and how to shock your pool. Do I need to get my CYA up before I start the shock process? With my test readings it says to add 120oz of bleach. Is it okay to add that much bleach at one time? Also during the shock process how much bleach should I add every hour?
Any help would be greatly appreciated and needed.
Thanks
 
Welcome to TFP, literally the best forum on the internet.

As you've read, shocking your pool is a process that's very heavily dependent on your CYA level. You need to bring your CYA level (using a standalone stabilizer/conditioner) to 30. At a CYA level of 30, your shock level is 13, meaning you need to bring your FC up to 13 and hold it there. You have algae in the pool, so the instant the bleach hits the pool, it will start doing its work killing the algae. This means the FC will start to be used up immediately, and will need to be replenished. Practically speaking, you'll want to test and redose every hour or two at the beginning. The usage will slow down, and your "redose" rate will slow down to 3 or 4 times a day.

As long as you're targeting a shock level appropriate for your CYA level, yes, it's plenty safe.

Again, it's not a "how much bleach per hour" question, it's "how often do I need to test and dose to keep my FC above shock level".

Does that make sense?

Also, how are you testing? You're going to get bombarded with suggestions (starting with me) to get one of our recommended test kits so you can do this thing right.
 
Thanks guys for the help. Right now I am just using the test strips, but looking into ordering one of the 3 test kits. Which is the better to get that will last the longest? Also where is the sponsor page to order it from?

I am a little confused about the shock FC level. Is that just the FC from the test strip? If I get the FC up to 13 to kill the algae how will it get it back down to normal range? How many gallons of bleach should I tell my wife to pick up for the shock process? Don’t want to run out and have to start over.
 
rkersh409 said:
Thanks guys for the help. Right now I am just using the test strips, but looking into ordering one of the 3 test kits. Which is the better to get that will last the longest? Also where is the sponsor page to order it from?

I am a little confused about the shock FC level. Is that just the FC from the test strip? If I get the FC up to 13 to kill the algae how will it get it back down to normal range? How many gallons of bleach should I tell my wife to pick up for the shock process? Don’t want to run out and have to start over.
http://tftestkits.net/splash-page.html Since you're facing the shock process, you should spring for the XL version. It has more of the test reagents for the chlorine test.

The chlorine will get consumed at an amazing rate killing algae. Sunlight will also break it down. Don't worry about it dropping down to normal. It will do that.

Have you studied Pool School at all?

There's no way of predicting how much bleach it will take. It depends on how much sludge is in there and how conscientious you are about testing and replenishing it. The better you are about maintaining the level, the faster things will go.

Check out the bottom of page one in this thread. :shock:
 
Yes I have read the pool school many times. With your help I am now seeing the overall big picture.

On the pool calculator CYA it says I need 44oz by weight or 46oz by volume or 114oz of liquid. Are the first two if I use granules? Just want to make sure I have this correct.

Again thanks for the help, it’s well needed. I flunked chemistry in school :)
 
rkersh409 said:
Yes I have read the pool school many times. With your help I am now seeing the overall big picture.

On the pool calculator CYA it says I need 44oz by weight or 46oz by volume or 114oz of liquid. Are the first two if I use granules? Just want to make sure I have this correct.

Again thanks for the help, it’s well needed. I flunked chemistry in school :)
You have it correct. Not everyone has a postage or kitchen scale to weigh out the CYA granules, but almost everyone has measuring cups somewhere.
 
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