How long to complete a SLAM and OFCT

[Mike in CA]

Hello,

I am a 2nd year pool owner and have been reading the site for a year and just now realizing how much great info there is on here.

Last year I spent the year bouncing up and down on my FC levels, so this year I learned about the SLAM and OFCT.

So after having 3 dogs and 10 people in the pool on 4th of July I again started my chlorine/shock/test approach and as you can expect I did not have good results. So I learned more and now I am into my 3rd day of a SLAM and OFCT cycle. I just cannot get the FC to hold overnight. I am loosing about 5ppm so each day I check the pool several times and add liquid Chlorine to bring the level up to the right shock level (using the CYA Table) but it just keeps dropping.

Sorry but I do not have all my numbers, but here is a good idea.

Pool, 18,500 gals.
2nd year Pebble tech finish
in sun 50-60% of the day
I usually use a solar cover but have had it off during the testing.

CYA 30
Trying to hold FC at 12ppm per cya chart

I can get all the other numbers but when I had the pool store check them they were OK.

We have had some small spots of algae that we could only see when swimming with gogles.

I have been brushing the pool daily.

Would just like to know how long the SLAM and OFCT should take? several days? a week? should I add more chlorine over the 12ppm mark?

Also, my wife is wonder if our solar cover is part of the problem. There is what looks like some algae on the edges of the cover, will this keep contributing to the problem?

Looking ahead to a much better summer,

Mike

 

[Richard320]

Three days is a little early to be expecting results. It didn't get messed up in three days, it will take more than that to clear it, too.

I certainly hope you're doing your own FC testsing, and not letting "the pool store check them they were OK."

Anything that might harbor algae - covers, toys, ladders, they all need to be exposed to the high FC levels during the slam process.

 

[Bama Rambler]

Which test kit do you have?
It's pretty hard to say how long it'll take. It's different for every situation.

When running the OCLT, You are testing after dark and about an hour after the last chlorine addition & again before the sun rises aren't you?

 

[Isaac-1]

There is a lot of variation, but for most minor outbreaks like you describe around a week is fairly normal. A lot has to do with how consistent you are maintaining shock level, and doing your brushing. For some people, particularly those that don't stay on top of their FC levels and brushing it can take multiple weeks. The good thing is once cleared it should stay clear as long as you stay on top of keeping the water balanced through regular testing and correct dosing.

Ike

 

[Mike in CA]

Hello and thank you for the 2 quick replies.

I do have one of the FAS test kits and I am using that for my FC.

I will do a complete water check this evening and see if there are any other areas out of normal.

Up to this point I think I have used 6 gls of chlorine (from Walmart) and a couple of bags of shock I had laying around.

It sounds like I am moving in the right direction and I thank you for the comments. Now that I know a bit more of what to expect I will get another 4~6 gallons of chlorine and continue the testing.

My pool does not get any sun until 10 AM or so, and then it is out of the sun around 6PM, so I have been doing the checking outside of those times.

I am not in a rush, just would like to have the pool in good shape by this coming Monday.

I will continue the SLAM and will update this post with all the other water tests tonight,

Mike