Cannot maintain FC in clear water

[doughboy]

I have used what I thought was an embarrassing volume of chlorine in the past month - until I read about other people using 100+ gallons. I've gone through 16 gallons of 12% and maybe 30-174 oz 6%. I feel like I'm wasting money, so I want advice before I proceed.

I winterize and have a solid cover. The pool was clear on opening and there seemed to be no problem initially. After a month or so I realized I was using more chlorine than last year. I read TFP so I know there are no gremlins stealing my chlorine - just sun and organics. The pool is covered most of the time, so it's not sun and it must be organics.

Using poolcalculator I figured 2-174 oz jugs would get me 15 FC shock level, so I shocked. I've got a DPD kit, so I can measure to 5ppm. I never measure shock levels. I've never had visible algae. I just trust poolcalculator and add the right volume. That chlorine was gone and I was still using high amounts. I shocked again (2-174 oz) maybe a couple of times. Still using lots of chlorine. I opted for high-end shock (4-174 oz). I did this a couple of times, brushed the sides several times, ran the cleaner often. Still high chlorine use.

I didn't have a CYA test, so I got a pool store test. My store is reputable, uses Taylor tests, and matches my tests for the ones I can do. The pool store said zero CYA. WTF? I know (or thought I knew) CYA doesn't go away. It should have been 30-40 based on fall closing readings. I didn't believe 0 CYA was possible, so I got a CYA test. I tested 0 CYA. Crud. I added several pounds of CYA and retested. CYA was at 30 and PH dropped a bit. Makes sense. While bringing CYA up I added a couple of gallons every day just to maintain FC.

Now that I had CYA I shocked again (4-174 oz). I don't have time to test FC every hour. The best I can do is twice/day. I tried to check 2X/day to maintain high levels. I can't test well over 5ppm, but I made sure I was over 5ppm and added (2-174oz) which should be +15ppm. I was trying to use the algae clearing procedure even though I don't see anything. I brushed a couple more times. I thoroughly power-washed and brushed my cover and the cover tracks to help get rid of anything that might be there.

Through all of this I measured CC levels at 1-2ppm at times, but never higher. I figured my 2-4 big jugs was enough to eliminate the CC.

I have not retested my CYA since bringing levels up because I assume it can't go anywhere, but I stumbled across the stories of CYA eating bacteria. Now I want to retest CYA to be certain.

I have seen red dots on the concrete coping that overhangs the fiberglass. I was told by a couple of people that it's probably bacteria, not algae and not a big concern. Brush it off, but don't worry. I've seen this off and on for the past 3 summers - never a lot just some dots here and there. After finding a couple of bacteria threads here, I wonder about the red stuff. I have seen it this spring, but not after all of my brushing and bleaching.

I'm stumped. Should I do the extreme chlorine demand bucket test? Should I test for ammonia on the bacteria theory?

Pool store commented the CH is a bit high and TDS. I know TDS (generally) doesn't matter based on reading TFP.

Current test
FC-5
CC-0
TC-5
PH-7.0
TA-120
CYA-30 (a couple weeks ago)
CH-350 (pool store)
TDS-3000 (pool store)

 

[JohnT]

What I'd try is holding at shock level for 3 or 4 days. You can test your shock levels with your kit by doing a dilution of 3 parts distilled water and 1 part pool water to get a reading of 1/4 of your actual chlorine level. Start it over the weekend so you can stay after it and test and add as necessary every 4 hours for the first several times. This will give you an indication of how rapidly the chlorine is consumed, and will also attack whatever is consuming your chlorine.

 

[frustratedpoolmom]

It does sound like you may have had the ammonia situation. You are doing the right thing, just keep shocking until the ammonia is oxidized and the FC holds.

I really think you would be pleased with an FAS-DPD test, to supplement your kit. Makes things alot easier. Both Taylor and TFTestkits.net sells the individual test for around $25.

 

[doughboy]

Two votes for "keep dumping in chlorine" ... so that's probably how I'll be spending my father's day weekend.

FC 0.5
CC 2.0
PH 7.2 (aerating since last test)
TA 120
CY 20 (dropped 10 in a couple of weeks)

 

[Butterfly]

Hey doughboy, make that three (3) votes!

Also, that FAS-DPD test would help you tremendously.

Good luck and get another bottle of POP.

 

[JohnT]

FC 0.5
CC 2.0
PH 7.2 (aerating since last test)
TA 120
CY 20 (dropped 10 in a couple of weeks)

If you do have something in the pool, anytime the chlorine drops down to 0.5, you've wasted all the rest of the chlorine put in previously. It's important not to let the chlorine drop below the suggested minimum in the Chlorine/CYA chart in Pool School. Even a few hours of low chlorine can set you back quite a bit.

 

[doughboy]

I continue to struggle with inability to hold CYA and FC. Since the last post I added CYA that should have been +30. That would take me to 50. I was aiming high since it was falling. I checked CYA today and it's about 30. It's still clear, but the chlorine levels are volatile to say the least.

I understand how the FAS-DPD test would help in this situation. I have tried diluting my sample with a DPD test to measure over 5, but I have little confidence in the results. Without the FAS-DPD I cannot hope to accurately maintain shock level.

I've got the FAS-DPD test on order. I've got an ample supply of chlorine and 4 pounds of CYA.

 

[Butterfly]

I suggest you check the % cyanuric acid in your CYA jug/bucket.

We have seen a couple reports of some being only 50% CYA.

Glad you ordered the FAS-DPD test.

Are you using a cover? If yes, leave cover off during the day to help burn off CC's.

Hope this helps.

 

[doughboy]

This season I opened with granular CYA from Leslie's, then I added a gallon of liquid for expediency. What I have on hand now is HTH CYA from WalMArt, which is 99% CYA.

I do have a cover. When I working on it, like this weekend I leave it open all day. Other days I toss in a gallon or two/day and hope for the best.

I've got a couple days off this week. As soon as I get the FAS-DPD I'm going to put this to bed and stop wasting money. Unreal.

BTW, It's still clear?!?

 

[doughboy]

I'm still working on this, but now I have the FAS-DPD test. I do feel properly equipped to shock the pool.

Sunday I maintained the pool at shock level (14-15 ppm). Monday I overslept, so didn't get an AM reading. Monday evening I was at 1.5. I ran it back up and kept it up Monday evening covering it about 10PM at 14. Tuesday morning @ 6:30 it was at 3, so lost 11 ppm overnight. I added 3 gallons of 6%, which should have put me @ 19. Tuesday evening @ 6pm I am down to 2.

Starting Sunday evening I dissolved CYA. I used a skimmer sock tied off and suspended over the skimmer basket. This worked great dissolved 4 lbs in 36 hours. I overshot my target a bit raising CYA to 60, but that's still okay.

I ran the pool vac on Sunday and scrubbed walls. I scrubbed walls again tonight.

I'm adding 3.5 gallons of 6% right now, which should get me to 20. I'll make sure it's about 20 when I close it tonight and test in the morning. I'm raising my target a bit due to the CYA increase.

Still no visible sign of organics. Water is clear. Sand filter is not showing a big pressure increase. I backwash 1/week. Curious. Staying the course and working on my P.O.P.

CYA 65
PH 7.0 (dropped with CYA addition)
TA 120
CL
Monday
- 14 @ 10pm
Tuesday
- 3 @ 630am (add 3 gal)
- 19 @ 630am
- 2 @ 6pm (add 3.5 gal)

 

[reebok]

it would have been easier to leave your cya at 30 and raise if you felt like it when you're done shocking, but glad to hear you have the fas-dpd test now. stay on top of it and the algae that's waiting to bloom in your water will be killed in its tracks. if you can check/add multiple times per day, so much the better.