Sudden Cloudy Water

May 26, 2011
82
I was testing my new PVC fountain to see if I could cool the water overnight and came home to a cloudy pool. Tested my water and got this:
FC 2
Ph 7.5
CC 0
TA 90
CYA 70

I added chlorine to get to FC 8. Any ideas what happened? Filter issue maybe? Thought I would ask before taking the filter apart
 
I'm by no means a pro, but it sounds like the start of an algae bloom. FC looks to be a bit low for that CYA level. Let's see what the real pros have to say.
 
thabeezer said:
FC 2
Ph 7.5
CC 0
TA 90
CYA 70

The root cause for the cloudy pool is likely not your filter but the low FC of 2 for a CYA of 70. The cloudiness you are seeing is very likely algae assembling in preparation for a blooming party. At a CYA of 70, you want to keep FC between 5 and 10 ppm at all times. Would suggest doing a partial drain & refill of about 30-40% to get your CYA down to between 40 -50 ppm. This will require less chlorine for shocking and ongoing maintenance. After refilling, then run a series of tests to determine your new CYA and whether you need to go through the Shock Process (likely).
 

Enjoying this content?

Support TFP with a donation.

Give Support
should be easy to get the FC level up easily. Just use pool calc and follow closely. Going to take a bit to get to shock level and keep it there, but should stop/kill any organic from exploding. Keep in touch!!!!!
 
I've been thinking about this a little bit. I have been using BBB for 2 years and never had a single problem. I test my water on Tuesday and Friday during swim season which has already started. I was in the pool the day before it turned cloudy and it was clear.

Is it possible that my aerator did something to the water for the algae bloom to get started? This is the most rain we have had since I have had the pool could that contribute to it?
 
Is it possible that my aerator did something to the water for the algae bloom to get started? This is the most rain we have had since I have had the pool could that contribute to it?
I doubt it. I think this is the culprit:
I test my water on Tuesday and Friday during swim season which has already started. I was in the pool the day before it turned cloudy and it was clear
Daily testing is recommended. Twice weekly, esp during swim season, is a real long shot.
 
I think that 1) your low FC/CYA ratio meant you were on the edge of algae growth in the pool and 2) testing the PVC fountain put things over the edge possibly due to algae in the PVC pipe that got flushed into the pool further lowering the chlorine level and allowing the algae to grow faster than chlorine could kill it.

I only test and add chlorine twice a week in my pool, but that's because I have a mostly opaque safety cover and therefore have a low 1 ppm FC per day chlorine usage even with the pool used every day. Without such a cover and with 2 ppm FC or more daily chlorine usage, I would think that one couldn't go more than a couple of days without adding more chlorine. If usage is very stable, then one might test less frequently though there's always the risk that something happens and you don't know about it because you skipped a test.
 
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.