Need Help Shocking My Pool Please

  • Last Post 10 June 2021
TJ1001 posted this 30 May 2021

I am new to doing the chemicals myself. I had a busted pipe for few months so the pool turned green, finally that is fixed so I began working on the green issue. I have vacuumed a few times. Pump is running. I tried to shock but doesn't seem to be working.

Levels BEFORE shock = Free Ch = .5, Alk 50, PH 7.2

Levels 12 hours AFTER shock ( 4lbs added) Free Ch = 10, alk 40, ph 6.8, stabalizer = 100

Today's reading ( 2 days later) = Free Ch = 3, Alk = 40, PH 6.8m Stab = 30-50

I have vacuumed and cleaned filter cartridges with water hose last night, they were basically black and full of mud and green yuck. That should help, but thinking I need to shock again since water is not that different, never got cloudy still just green. Do I have to add anything else or just keeping shocking?

Any advice is appreciated, apologies if I added to wrong spot or there is other post that answer, I am new to forum stuff, but I have read thru a bunch of post and have no doubt this group can probably get me going in the right direction -- thanks 




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TJ1001 posted this 31 May 2021

Update to this post, Above shock was done last week, then Saturday I cleaned  the filters, still very dark green water color, so shocked again on Sunday with 12 lbs of shock. 

Monday post 2nd bigger shock - PH 7.8; FC 10 + ( strips only go to 10); TA 40; S 30-50. 

Going to try and maintain a high chlorine level for few more days and keep the pump running to try and go blue. It is raining again today, so that is not helping. thanks. If anyone has any other ideas, do let me know, thanks

JCMC70 posted this 31 May 2021

Hi Tj1001


I think I can help you with your issue, but I’m gonna need more information. 

A little background on me:

My pool was installed in 1987, so I have 34 years of pool maintenance. I’ve gone through everything from opening my pool with water so dark green it was almost black to bouts with green algae, a small pink algae bloom and 1 nasty bout with mustard algae. 

Years ago I went to maintaining my pool with nothing more than chlorine, baking soda, borax and muriatic acid. Since then my pool is crystal clear within 5-7 days of opening it and says clear for the swim season. 

That said, the main things I need to know are:

  1. What kind of pool do you have? Vinyl, gunite/plaster, concrete, fiberglass.
  2. How many gallons of water does your pool hold?
  3. What kind of chlorine do you use for normal chlorination of the pool?
  4. What kind of shock have you been using?

And a couple of observations:

  1. In your post you said that the test strips only go to 10 ppm chlorine. With all respect, test strips are notoriously untrustworthy...worthless. If you are serious about maintaining the chemicals in your pool, the first thing you need is a good test kit. 

There are 2 that are recommended. The Taylor K-2006 and the TF-100. Both kits test for chlorine using the FAS/DPD method. FAS/DPD lets you test for high levels of chlorine(up to 50ppm). 

I use the Taylor kit but both kits use Taylor reagents. Price ranges for both are $70-$90, but I saw a Taylor K-2006 on eBay for about $65.00

  1. In one post you said the stabilizer level is 100 and 12 hours later it was 30-50.

How did you get it to drop by 50-70ppm?


Please answer my questions, get me a recent set of readings for free chlorine FC, PH, total alkalinity TA and stabilizer CYA.

And order a good test kit. 

We will take it from there. 



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Service posted this 03 June 2021

I totally agree with J on the test strips not being that great, I second the TF-100 Test Kit I use it on my pool. I especially like the powder and dropper method of testing your chlorine as it allows you to get precise measurements on your chlorine especially if you are going higher on your chlorine (i.e. above 10 PPM).

Thank You


TJ1001 posted this 08 June 2021

Thanks for the responses. Very thankful for the advice.

Update: It has been raining here, which does NOT help matters. My polaris cleaner is on the fritz now too. I have taken it out cleaned it, realized he lost his tail, found it put. back on, but he lost again in less than an hour. I have now zip-tied back on and adjusted the screw so the tail goes slower ( found that on a video on this site, thank you). He seems to be moving now, but the back wheels won't stay on the bottom so he gets stuck on a corner, that is a separate issue, but would help my overall situation if I could get the bottom cleaner I think. I ordered a proper test kit, thanks for the recommendations. 

I have inground pool, best calcs I can come up with is about 16k gallons. I think it is regular plaster. I have DE cartridge filters, which are incredibly old and need replaced, that is ordered too, but was hoping to get it clean with the old ones. 

I have been using 56% active ingredients shock from Walmart ( red writing on the bag, can't remember the name). I bought the pool blast shock from Inyo just arrived, so this round will be done with the new kit and new shock. Hoping that helps. Other question on the stabilizer levels bouncing, I did add some baking soda at one point trying to raise my Alk. but also those two numbers are right next to each other on the strip. It says 30-50 ad next color is50-100, so might not be as different as we think. New test kit not in yet.

Ok today's reading ( same strips) 

PH 7.2, FC, 10 +, Alk 40, Stab 30-50. Color is teal green. Bottom is darker, need brushing to stir it up before I shock again ( I think) 

Side questions: I tried vacuum manually to get the bottom cloudy stuff up, but seems like it just sends it straight to my big filter and clogs up so quickly. Is there a way to vacuum out to the yard? I can't see how putting all that back in my system is helping? Feels like a loosing battle. thanks guys! sorry for long post .



TJ1001 posted this 08 June 2021

OH - and normally I use cholorine tabs in a floater for regular use and if needed ( raining) I will toss in some granules in the skimmer or just in the pool. I don't add anything else, ever. I did not even have a test kit until this time around. I have kept my pool blue for 2 yrs using only chorline. It has gone green few times, but I never close it down. THis year we had snow and it iced over, have been trying for 2 months to get it blue. Feeling over my head, lol

JCMC70 posted this 08 June 2021


Let me address your questions and then we'll come up with an attack plan. 

"Side questions: I tried vacuum manually to get the bottom cloudy stuff up, but seems like it just sends it straight to my big filter and clogs up so quickly. Is there a way to vacuum out to the yard? I can't see how putting all that back in my system is helping? Feels like a loosing battle"

If you have a setting on the dial valve on top of the filter labeled "waste" or "drain" then yes, you could theoretically vacuum the pool and have the water bypass the filter. There is one major drawback to that (and some minor ones). The major drawback is unless you have a main drain in the pool, the water level would fall too low for the skimmer to pull water into the pump and filter. I know it's gonna be a hassle and a lot of work, but the least expensive option is to vacuum to the filter and backwash when the pressure tells you to. 

"and if needed ( raining) I will toss in some granules in the skimmer or just in the pool"

You should ever put chlorine granules in the skimmer or directly into the pool. Tossing them directly into the pool could damage/fade the plaster. Always dissolve the granules in a bucket of water and pour that into the pool in front of a return. 

This would be my attack plan going forward:

You have a lot of algae and maybe other organics in the pool. So it needs to be super chlorinated. And that super chlorination needs to be maintained. Ideally the pump should run continuously throughout this process. Realistically, the pump may not be able to run through the night without making the pressure in the filter so high it needs to be backwashed. You will have to make that determination. 

Before you get the new kit: 

We will use the chlorine reading the test strips give you.

The shock level for a 16k pool is 16 ppm. So take a new chlorine reading and subtract the number you get from 16. That's how much you will need to raise the chlorine level in the water.
3oz of 68% cal-hypo should raise the chlorine level of 16000 gal of water by 1 ppm. So take the number you got when you subtracted the chlorine reading from 16 and multiply that number by 3. That will give you the total ounces of shock needed to bring the chlorine level to 16 ppm(remember to dissolve the shock before adding it to the pool).

Then let the filter run but be sure to backwash it when the pressure reaches that point. At the end of 3 to 4 hours take another chlorine reading. Subtract that number from 16 and repeat the process outlined above. You need to do this every 3-4 hours (if possible) until you go to bed. In the evening before the sun goes down, take the final chlorine reading for the day and bring the level up to 16 ppm. If the filter will go without needing to be backwashed during bedtime, let it run. Otherwise let it run until your ready for bed and shut the pump down. Start it up in the morning with a new chlorine reading.

At least once a day you should vacuum the pool. Brush the pool bottom and walls once a day, preferably in the evening so whatever is suspended will have a chance to fallout before the next vacuum.

As the algae and contaminates are killed, you notice that the amount of chlorine you need to add to keep the level at 16 ppm is less and less. And the daily vacuuming will clear the water.

When the pool holds the chlorine level overnight (within.5 - 1 ppm) and the water is clear and the combined chlorine level is 1 ppm or less, you are done.

After you get the new kit: 

Use the 10ml sample to test for chlorine. This will give you readings in increments of .5 ppm and that's all we need.

I would also look for a replacement bottle of the R-0871 titrating agent cause you will probably use a lot.

After the pool is clear we will look at the other things like total alkalinity, stabilizer and because the pool is plaster the calcium hardness is crucial.

Let me know if you have any questions.


TJ1001 posted this 08 June 2021

Perfect, thanks for all the detail. I am going to get to work. I'll follow up in few days or if something goes wrong, lol. 

TJ1001 posted this 09 June 2021

ok, well tonight was a disaster. I went out to check on it, the pump was running, was trying to fix my Polaris earlier today, so was testing it out. The skimmer popped off and the pressure was high on the filter, so I took it apart and cleaned it. Cleaned the skimmers, they were covered in algae ( which is a first, the pool is cleaner now than it has been in 2 months, and this is the first time algae has made it to the skimmers, but ok, I guess it is better to come out somehow).

I put it back together, but the filter is leaking a little from the middle, perhaps I cannot tighten it enough. Pressure is staying at 40 and the basket on the pump with a clear lid won't get full. I did add water to the system before I turned it back on and let the air out of the top, but I think I am missing something... 

Any advice? I will try again tomorrow, thanks 


JCMC70 posted this 10 June 2021

How many skimmers does the pool have?

what is the normal filter pressure when the filter is clean?

Is there a two way valve that the plumbing coming from the skimmers connects to before the water goes to the pump?