This has been a weird one the past few days. Our pool is just under 10k gallons. It is a combination pool/spa where the hot tub has a spillway even with the pool water. Under normal operation in the summer for the past three years I occasionally have to use a little acid to bring the ph down because general use, off-gassing, etc. just builds the ph up slowly.
A few weeks back we had a storm drop a branch on the pool plumbing while we were out of town. So no filter was running, etc. at all, for about one week. We had my mom run the pool robot and add in a little liquid bleach each day and all seemed OK when we got everything back up and running. For the next several weeks, no issues at all. I use regular bleach for the pool. Rarely ever use pucks except at the start of the year to get the CYA up to the right level.
Fast forward to 2 days ago. There has been a lot of rain and storms in Charlotte, so I admit I was not the best at keeping everything super clean and chemicals right but when I went out after the latest storm both skimmers were chock full of leaves and the water in the pool was very cloudy. Almost a milky white. I look closer and it does look like water mold growing in there with slimy white tendrils. I get everything cleaned out of the skimmers and skim the pool with my leaf rake, get the robot going, etc. Check the chemicals again to be sure I'm good and all of a sudden my PH is super low and I am showing no free chlorine. OK I think. That's on me. I'll shock the pool and let the PH come back up (it was at 6.3) as I work on this. I put two entire gallons of 10 percent liquid shock in the pool, and ensured everything else was right (I did have low calcium hardness and the alkalinity was slightly low, at about 50, and CYA was almost gone. Only showing 5ppm on stabilizer. I brought those up and let the pump run) The pump runs 24/7 so the next day the pool actually already looked a million times better.
I tested it again and PH is still right on 6.3 and I'm showing 0 free chlorine less that 12 hours later. Hmmm... So I actually use some soda ash to adjust the PH now and later that night it's up to 7.2. Seems like we're heading in the right direction. So PH 7.2, Alkalinity was at 135, so slightly high but not out of bounds. Two more gallons of 10 percent pool shock go in. Next morning I check again and the PH is 7.1 so holding steady but again, no free chlorine and total chlorine is only showing about 4.5 ppm at that point. I take a sample to the pool store to see if they read the same thing I do. They show slightly higher free chlorine but almost everything else matches my test.
Decided at that point to see what this morning brings. So this morning I test again the PH has crashed back down to 6.3 again. No free chlorine at all and total chlorine is only showing about 1.5 ppm. This was after using soda ash to bring the PH up the day before and having shocked the pool twice in two days.
What am I missing here?
The water actually looks pretty good. It's clear. There are handful of leaves in the pool as speak but nothing else. No other signs of stains, algae, anything. When I brush the walls and floor I'm not stirring anything up. The robot cleaner isn't either. Visually it looks good but for some reason my PH keeps crashing down to very acidic levels and just a few hours after shocking the pool with a heavy dose of chlorine, I'm essentially showing no free chlorine and really not even that much total chlorine.
Am I missing something with chemical balance here? Or is it possible I really just had that much organic material for chlorine to deal with over these past couple of days and it will even out over the weekend?
A few weeks back we had a storm drop a branch on the pool plumbing while we were out of town. So no filter was running, etc. at all, for about one week. We had my mom run the pool robot and add in a little liquid bleach each day and all seemed OK when we got everything back up and running. For the next several weeks, no issues at all. I use regular bleach for the pool. Rarely ever use pucks except at the start of the year to get the CYA up to the right level.
Fast forward to 2 days ago. There has been a lot of rain and storms in Charlotte, so I admit I was not the best at keeping everything super clean and chemicals right but when I went out after the latest storm both skimmers were chock full of leaves and the water in the pool was very cloudy. Almost a milky white. I look closer and it does look like water mold growing in there with slimy white tendrils. I get everything cleaned out of the skimmers and skim the pool with my leaf rake, get the robot going, etc. Check the chemicals again to be sure I'm good and all of a sudden my PH is super low and I am showing no free chlorine. OK I think. That's on me. I'll shock the pool and let the PH come back up (it was at 6.3) as I work on this. I put two entire gallons of 10 percent liquid shock in the pool, and ensured everything else was right (I did have low calcium hardness and the alkalinity was slightly low, at about 50, and CYA was almost gone. Only showing 5ppm on stabilizer. I brought those up and let the pump run) The pump runs 24/7 so the next day the pool actually already looked a million times better.
I tested it again and PH is still right on 6.3 and I'm showing 0 free chlorine less that 12 hours later. Hmmm... So I actually use some soda ash to adjust the PH now and later that night it's up to 7.2. Seems like we're heading in the right direction. So PH 7.2, Alkalinity was at 135, so slightly high but not out of bounds. Two more gallons of 10 percent pool shock go in. Next morning I check again and the PH is 7.1 so holding steady but again, no free chlorine and total chlorine is only showing about 4.5 ppm at that point. I take a sample to the pool store to see if they read the same thing I do. They show slightly higher free chlorine but almost everything else matches my test.
Decided at that point to see what this morning brings. So this morning I test again the PH has crashed back down to 6.3 again. No free chlorine at all and total chlorine is only showing about 1.5 ppm. This was after using soda ash to bring the PH up the day before and having shocked the pool twice in two days.
What am I missing here?
The water actually looks pretty good. It's clear. There are handful of leaves in the pool as speak but nothing else. No other signs of stains, algae, anything. When I brush the walls and floor I'm not stirring anything up. The robot cleaner isn't either. Visually it looks good but for some reason my PH keeps crashing down to very acidic levels and just a few hours after shocking the pool with a heavy dose of chlorine, I'm essentially showing no free chlorine and really not even that much total chlorine.
Am I missing something with chemical balance here? Or is it possible I really just had that much organic material for chlorine to deal with over these past couple of days and it will even out over the weekend?
