Slamming can't get FC any higher that 16

[glamaina]

Well the title pretty much says it all but I recently had an algea bloom do to my own neglect. So I started a slamming this morning. Brushed it all up and tried to raise the pool to mustard algea levels based on my cya level of 40. That target was 24 ppm.

I cannot get the fc above 16. Is there any reason anyone can think of other than faulty liquid shock?

Pool math says add 128 more ounces so I do that and check back a few hours later and the levels are identical to what they just were. I feel like I'm crazy.

 

[mknauss]

The chlorine is being consumed. Keep testing/dosing every couple hours.

Also -- you stated 'mustard algae'. That is a pretty specific form of algae that takes a specific process. It sounds like you have the normal blue-green algae.

Take care.

 

[glamaina]

I mention mustard algea because I've been trying to deal with what I assume to be mustard or yellow algea for a few seasons now. It's brownish and keeps reapearing in the crevasses of my floor. I go through periods where I convince myself that it isn't algea at all, maybe pollen or something else because I've slammed the pool several times in the past until no CC and no overnight loss. Still if I don't agitate the water for a few days this brown stuff starts to reappear. I tried vacuuming to waste, still reappears.

So this time now that I truly know I have algae of some sort as it was everywhere, I want to make certain and slam to mustard algae levels.

 

[mknauss]

OK -- then read this - Pool School - Mustard Algae

 

[Akathisia]

Are you sure about your pool water volume you are using in pool math? Have you entered the correct percentage for your bleach source? I recommend testing your FC 30 minutes to 60 minutes max later to see what the FC is. That way you can get a better feel for how much bleach to add.

 

[Richard320]

How about some test results? And how does the water itself look? We can deduce that there is algae on the walls, but is the water clear or cloudy?

If, for instance, you used to have CYA but now you don't, it could have broken down into ammonia, which will consume bleach about as fast as you can pour it in. Likewise, a murky green swamp will consume FC nearly that fast.

 

[glamaina]

pH 7.4
Cya 40 (been 40 for the last month)
fC 9ppm
CC <0.5

Water is Crystal clear. And was when I noticed the algea as well. No visible algae on the walls only the floor.

This morning fc was 15 and cc was 0. I dumped 2 gallons of 12.5% bleach before work. When I got home at 6 pm I tested it and I'm at 9ppm. Like I said water is clear so how can something be eating this much FC?

There is still cloudy stuff coming off the floor when I brush but much less.

 

[mknauss]

You are two days into a SLAM. Patience. You still have stuff on the floor of the pool, that is dead algae. That is being killed by the chlorine. Stay at it. If possible test/dose more often, it will shorten the length of the SLAM.

Take care.

 

[glamaina]

Yes gallons are correct and percentage is correct. I've been following the pool school rules for a few seasons and the chlorine calc has always been pretty accurate. I just added another gallon. I will check in an hour to see where I am at.