From crystal clear perfection to cloudy - help!

May 24, 2018
75
NB, Canada
Hi all,

This is my first full summer with my pool. I had nailed the water balance and everything was going great. We had a ton of rain over the last 2 weeks, which led me to having to pump out some of the pool water to get it below the skimmer top a few times. I did keep checking FC and pH. FC would go up during rainy periods (SWG still running but no sun and no bathers) and I had to lower my SWG a bit a few times, but put it back to it's sweet spot once the weather cleared up. pH did not really move, even with all the rain (I run around 40ppm borates, so very stable pH now).

Anyway, with a lot of pool use in the last 4-5 days, I noticed that the pool was a little cloudy. I immediately checked and FC was down to 2ppm. I set my SWG to Super-Chlorinate (i.e. 100% for 24 hours) - in the past it would take no time to shoot the FC up. Not this time. I checked again 6-8 hours later and FC was still around 2. I dumped half a gallon of bleach to get it up there. Prior to putting the solar cover on the pool end of afternoon yesterday, FC was 5 (because of the bleach). When I checked this morning, it was down to 2 again. I dumped 1.5 gallons of bleach (which should add 10 FC according to pool math).

This morning's tests:

FC 2 (prior to adding bleach)
pH 7.4
TA 70
CH 300
CYA 50 (was 70 earlier this season, must've lost some during the pumping, although I can`t imagine I lost that much). I added some stabilizer this morning to hit my 75-80 CYA target.
BOR 40-ish
SALT 1600 (added 20 lbs this morning, should get me to 2000ppm)
TEMP 86


So, why is my water cloudy? Would the FC dropping to 2 cause this?

I've read that high levels of CH in high water temperatures can cause the CH to suspend in the water and cause cloudiness. Would that happen given my CH levels and temp?

My filter pressure is fine, not indicating it needs a cleaning. I do plan on cleaning it in the coming days once the stabilizer I added is fully dissolved.

I am having an issue with SWG though, which is probably why my FC dropped to 2. It seems like my flow sensor is not detecting flow when my pump is running at it's low speed (1100rpm), which is what it runs at all day. It worked fine up to yesterday. Perhaps my flow sensor is going bad or there is something restricting pressure in the line. It does detect flow when I increase pump speed to 1500rpm, which is what I've manually set it to for now.

Thoughts?
 
Cloudy water and your SWCG flow sensor indicating low flow point to algae and a filter that is getting plugged. Are you cleaning the filter when the pressure rises by 25% over clean pressure?

Adding the CYA was not the best move. Your SLAM FC will be higher. Follow the SLAM Process
 
Darn. Yes, it is not at the 25% mark yet. I had very successful SLAM in early June. Dissapointed to have to do it again. I will clean filter tonight when I get home and perform an OCLT to see what's up.

Yes, you're right, I didn't think I would need to SLAM again so will need a ton of bleach to keep things at shock level. Hopefully it will be a quick SLAM this time. Prime pool season!
 
No CC is not weird. CC is burned off pretty easily. CC is primarily generated from ammonia compound destruction by the chlorine. Most of that in pools is human caused.
 
Thanks. I did a test this morning at around 9AM. Pool was covered all day (solar cover). Did a test at 3:15PM and did not lose a single ppm of FC during this period (and did not add). Also CC 0. Perhaps premature but to not lose FC during 6+ hours of daytime is a pretty good indicator. Also, the pool seems to have cleared up. Photo to follow. It is not as sparkly as I got used to (unless it's in my head, but it is very clear in my eyes). Looks like filtration was the culprit which may have allowed initial stages of an Algae bloom to start when the low flow turned off the SWGC. Whatever it was, it appears like not much is living in the pool right now but will confirm overnight with OCLT. Pretty quick SLAM (less than a day)...
 
Passed OCLT with 0 FC loss overnight. Pool is clear. Thanks for the help, Marty. Quick and painless SLAM, now to let FC drift down. Not super comfortable with people swimming in 28FC (shock level) but I left the solar cover off today so hopefully the sun burns off a lot of it.
 

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