Water Green, Not Consuming FC, No CC


New member
Apr 22, 2017
Macon, GA
I purchased a home with a 20x40 vinyl inground pool last year and by using this site I was able to get the pool up and running and maintain it myself. However, this year I am not off to a good start. I removed the cover on Monday (Apr 17). The water itself was crystal clear but there was a layer of green on the bottom with a small amount of leaves. I started the pump and scrubbed the entire pool and got all the leaves out. As expected the water turned cloudy and green. I ran the pump for 24 hrs and took initial readings. Unfortunately I only measured CYA, FC, and PH. The results were as follows

CYA = 0
FC = 0
PH = 7.2

I figured I would bring the FC up to 5ppm and at the same time add enough stabilizer to raise the CYA to 30ppm. I used the PoolMath calculator and added bleach (10%) and CYA. The CYA was added via a pantyhose in the skimmer. Since Tuesday (Apr 18) I have checked the FC, CYA, and CC daily. I checked the FC and CC every hour and the CYA once a day. I adjusted the FC to the recommended shock level as I measured an increase in CYA.

From Tuesday (Apr 18) to today (Apr 22) I have had virtually no loss in FC overnight or during the day. No change in color when adding R-003 to check CC. The only time I have had to add chlorine is when I have measured a change in the CYA and needed to raise to the proper shock level.

At this point I have a CYA close to 50 which is odd because I used the PoolMath calculator to add just enough to bring it from 0 to 30.

I have also noticed that when adding the recommended amount of 10% bleach to bring it to my target it seems when I measure the FC it is 4-5 ppm higher than the target an or so later. Pool has shallow end of 3ft and a deep end of 8ft and I have been using 33,000 gallons as my volume.

I am not sure why the pool would still be green but consuming no FC and producing no CC.

I have been using the TF100 test kit.

After the first day I backwashed the filter and it was totally green. Since then I have seen no rise in pressure. I replaced the sand and laterals last year as well as the bearing and impeller in the pump. I did pop the 6 way valve off this morning to see what it looked like and the sand appeared clean with some nickel shaped leaf pieces on top. Other than that nothing. The four returns have good output.

I have been brushing everyday.

Here are some pictures.
Monday April 17

Wednesday April 19

Saturday April 22


Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Hello and welcome to TFP! :wave: Well, you have a couple very good things going for you right now. You have a TF-100 and your pool is holding CYA (50). :goodjob: As for the green and progress on cleaning the pool, you probably know a "SLAM" is in order (link below). So let's recap a few basics:
- Adjust pH to 7.2; lower with muriatic acid if necessary.
- Don't add anymore stabilizer.
- Increase FC to the SLAM/shock level of "20" per the Chlorine/CYA Chart (link below)

Review the SLAM page at least once daily to refresh your memory on what needs to be done. We can never overestimate brushing. Take a picture each day to monitor your water progress. And most importantly ... be patient. A pool didn't turn green overnight, so it takes a few days or so to revert back. But if you follow the SLAM page carefully, it will be TFP clear before you know it.

Let us know if you have anymore questions.