Issues SLAMing

[mrCide]

I'm in SE Florida and have been doing TFP method for about a year and a half. Over the last spring either due to bad circulation or not staying on top of FC I had some algae start on the floor and corners of the pool steps (and along the auto cleaner hose). 15k pool with about 45 CYA

This last week I've been attempting to SLAM to clear the algae. During the week I could only add chlorine in the morning and evening. It would at 5FC or so at 6pm every day and I'd bring it to 16-17, double check/add if necessary around 8pm. After a few days and brushing the spots are gone, but I kept doing this all week since I kept having FC loss in the morning. CC during these tests was either non existent or .5 or less. Pump has been on 24/7 during this.

The weekend I went ahead and added chlorine throughout the day, last night bringing it to 19 FC. This morning I was at 15FC. 4FC loss overnight seems rather high considering everything mentioned. Water never actually got cloudy and I've cleaned the filter as well, the only thing I can think of is that the water is just too warm to hold it overnight (it is rather warm even early morning), but I don't see that mentioned anywhere.

Any thoughts?

FC - varies, 5-19
CC - <.5
PH - 8
TA - 80
CH - 285-300
CYA - 45

TF100 kit

 

[Chris19D]

Hello mrCide. Could you please post a full set of your results and let the experts know what test kit you're using?

FC -
CC -
PH -
TA -
CH -
CYA -

 

[Jezza]

A loss of 4 FC is not uncommon when you are in the middle of a SLAM. Algae does love warm water and your OCLT indicates that you haven't gotten on top of it yet so it will continue to consume your chlorine.

We round up CYA to the nearest '10' so you should be SLAMming as thought it were 50 CYA which would make it a 20 FC SLAM level.

 

[Richard320]

There's still something in there.

Check all the hiding places beneath steps and lights, beneath ladder rungs, even in the skimmer throat. And if there's a bunch of debris in the baskets or the filter, it's still there stealing FC even if it's not actually in the pool. It probably wouldn;t hurt to give the cleaner a look and a brushing, too.

 

[Donldson]

Warm water does not cause that kind of overnight loss, 4 ppm is significant. Clear or not there is something in there still reacting to the chlorine and ending the SLAM is just going to give it the chance to grow.

This is the part where you want to check all the nooks and crannies where algae can hide. Brush or vacuum every inch of the pool, check ladders for spots of algae, remove a light if you have it, anywhere that might not be getting enough circulation. Just remember that even if you don't find much that algae is microscopic, clear water does not mean it isn't there. Oh, you should also round your CYA up to 50 so dose to 20 FC. I don't think that was a problem but should help it not dip as low.

You are handling this right, this is just the hard part near the end of the SLAM where you have to trust the test results and not your eyes. Keep at it, especially with warm water you want to make sure you finish the job correctly and avoid doing it again in a couple weeks.

 

[mrCide]

Thanks for all the feedback.

I did clean all the hoses and the cleaner (Poolvergnuegen), as well as the LCF and all baskets. Went around the pool with a brush and went at the stares/steps/light, too. Funny that before last night the drop was 1-2 FC overnight, and last night was 4 when I had more FC before sleeping. Just bizarre. I had the drain valve closed since I had the vacuum and skimmer going, so I opened that up some a few days ago to get water circulating on the bottom and through the drain in case there's something in there.

Guess I'll just keep at it and try to maintain at 20.