Something chewing up my CL

[Ssouthar]

Hey everyone. I need your thoughts on this. Haven't posted here in a really long time. My chemistry has always been rock solid. I test every morning for temp, CL and PH and then do the full test once a month because the others hardly ever drift. About a month ago, I was having issues with the CL and having to dump 32oz in the pool every day and then it dawned on me (smacking forehead) that we had had some record rains here in the Sacramento, CA area and probably my CYA was low. Tested and sure enough, it had practically zeroed out from all draining and I had been doing. Added CYA and brought it back up to 50. I nomally have very close to CL 5.0 and add between 12 and 24 oz per day to keep it there. PH is almost always 7.6 but was 7.8 thid morning and added 6oz to knock it down. CYA is still 50. Last monthly test was just last week and My chemistry is currently CL 2.4 PH 7.8 (added acid just now to bring it in line. Temp is 77. The rest is as follows
TA 70
CH 390 - added 11 lbs of calcium chloride to bring it up from 340. Interestingly enough, this CL issue started a couple days later.
I dumped over 50 oz of CL 12.5 in there two mornings ago, forgot to test yesterday but it's now down to 2.4. I buy it from All Clear Pools which keeps a good stock of very fresh stuff so I dont' think that's it. Could it be my regents? I buy in bulk because I test so often but my CYA and CL regents are within date window. What the heck! I do have solar rings floating on the surface but had them all summer last year with zero chemistry issues so I fail to see how that could be it. I cleaned the filter months ago and everything seems fine there. In fact, I installed brand new Hayward cartridges at the time.
Any thoughts?? This just started about 4 days ago.

 

[mknauss]

Do an Overnight Chlorine Loss Test. Raise the FC to 5 ppm to do the test.

 

[Ssouthar]

Thanks! I’ll do the test and let you know. I’m assuming if it’s over 5 as the sun goes down, it shouldn’t matter as long as it’s the same the following morning before the sun hits the water. Correct? I’ve done this test before a couple years ago.

 

[Ssouthar]

Thanks! I’ll do the test and let you know. I’m assuming if it’s over 5 as the sun goes down, it shouldn’t matter as long as it’s the same the following morning before the sun hits the water. Correct? I’ve done this test before a couple years ago.

Hey Marty, I'm sorry I kept forgetting to do the test before bed. Finally set an alarm and got it done just after sunset. Repeated at 5:30 this morning and results were spot on the same. 4.4 and 4.4 I buy my reagents in bulk, particularly the DPD Titrating and DPD Powder. The Titrating is way out of date by 7 months and the others are still ok. If that's the culprit, I find it out that it would just drop off the cliff like that rather than slowly giving worse inacurate readings over time.

 

[mknauss]

Sounds like you do not have algae. Just manage your FC at target level based on your CYA level.

 

[PoolStored]

Hey Marty, I'm sorry I kept forgetting to do the test before bed. Finally set an alarm and got it done just after sunset. Repeated at 5:30 this morning and results were spot on the same. 4.4 and 4.4 I buy my reagents in bulk, particularly the DPD Titrating and DPD Powder. The Titrating is way out of date by 7 months and the others are still ok. If that's the culprit, I find it out that it would just drop off the cliff like that rather than slowly giving worse inacurate readings over time.

Start testing FC with 10ml of water. Each drop is .5 FC. Will really save you reagents...

 

[Ssouthar]

Start testing FC with 10ml of water. Each drop is .5 FC. Will really save you reagents...

Good point!!

 

[Ssouthar]

Hey Marty, I'm sorry I kept forgetting to do the test before bed. Finally set an alarm and got it done just after sunset. Repeated at 5:30 this morning and results were spot on the same. 4.4 and 4.4 I buy my reagents in bulk, particularly the DPD Titrating and DPD Powder. The Titrating is way out of date by 7 months and the others are still ok. If that's the culprit, I find it out that it would just drop off the cliff like that rather than slowly giving worse inacurate readings over time.

Ok thanks . I'll carry on then. I just go crazy over little things like a sudden CL level getting chewed up for no obvious reason. That's just me - perfectionist. LOL!