Maybe I'm wrong but....


Jun 2, 2016
Hi everyone,
I've had my pool for almost 20 years and it's only in the past few that I'm learning about the chemistry. I have a 30k gallon, gunnite pool with a DE filter. I'm not sure if I'm correct in what I'm about to say so please correct me if I'm wrong and if I'm right it might just help someone.

The past three years I've been watching my CYA and trying to maintain an adequate level between 30-80. Towards that end I noticed that my pool shock is a dichlor and that raises the CYA so I've also purchased Calcium Hypo in powdered form. I would use the Cal Hypo to shock and raise the chlorine levels. Over time, I began to notice a greyish-white powder form on the bottom of the pool as sort of a ring around the pool. I also saw that my automatic vacuum would pick the stuff up and since my vacuum shoots water out the top it would mix whatever it didn't catch back into the water. I'd see a cloud that would dissipate as the day went on. For two years it seemed like the powder was always there. There were times I believed that it was algae that was dropping to the bottom of the pool except the stuff had the consistency of sand so I wasn't quite sure.

This year I opened my pool and the typical green went away in three days to be replaced by a very cloudy blue. I shocked with the Cal-Hypo and the water wasn't clearing up. After about a week I got fed up and had the pool store analyze my water just to see how my Taylor Test Kit was doing. Did I have old chemicals from last year affecting my readings? Was the cloudiness algae (although I can't imagine white algea)? After my first two backwashes and adding more DE the pressure stabilized where it should be (18-20). This told me that whatever was in the water was not being caught in the filter. Am I wrong? I seriously began to be concerned.

I began by balancing my PH and my Alkalinity and then adding liquid Chlorine (the 10% stuff) from Walmart. I added 9 gallons of the 10% stuff. The pool cleared began clearing. Questions I have: Was it the 10% chlorine that cleared the pool? Was it the filter finally getting the better of the stuff (although the pressure on the filter was stable)?

I believe that the use of the Cal-Hypo in powdered form caused the problem. It was a 70/30 active/inactive powder. Could it be that the inactive powder was not mixing into the water and falling to the bottom or remaining suspended in the water?

The last thing I can think of because I started to listen to the videos from TFP. I don't open my own pool and I know that since I have well water the company that opens my pool adds something to remove the iron. Could it be that there is a reaction between the chemicals?

So where am I? All of the above or none of the above or a mix of things?

Perhaps what happened to me will help someone else that has someone else open their pool and sees cloudy water not being trapped by their filter.

- denis


Mod Squad
LifeTime Supporter
Jul 10, 2012
Tallahassee, FL
The liquid chlorine is what cleared your pool. The powder stuff was adding CYA or CH depending on which one you were using at the time. It is not really good enough to clear a pool. Too much of CYA or CH is not a good thing. Have you tested your CH?

Please run and share your latest test results.