Question about SLAM

[mikefamig]

This is about my third year using the TFP method of sanitizing pool water and I have a question.

I've kept notes of my test results and each year I have had a similar experience each year. The pool opens with fairly clean water. I manually scoop out the dead worms from the bottom and run an Aquabot and hand skimmer net to remove the rest of the silt and debris. I start the system with a slam that takes weeks to get to a point that the free chlorine becomes stable for any length of time. I am using one to two gallons of chlorine/day and this keeps up for a couple of weeks when the water will finally hold a steady chlorine level and pass the OCLT.

This year I started the slam at 30ppm CYA and was maintaining a 16ppm FC level. Now I am at 50ppm CYA and maintaining a 20ppm FC level. I am adding a gallon or two od 12.5% chlorine per day to maintain the shock level. The pool is 16x32 inground and approx 18000 gallons of water.

The only thing that I can think is going on is that there is a lot of new bad stuff getting into the water. The pollen is terrible here in Connecticut right now and the pool is near a bunch of white pine trees and forsythia bushes. The water has been clear from a couple of days into the process. I did sadly find a chipmunk in the skimmer a few days ago that knocked the chlorine down by a bunch but I caught it quickly.

My question is whether anyone else here has taken so long to clean up the water on opening? Any ideas are welcome. After three years I still don't know what I can do differently. The water does eventually clean up but it takes a very long time and a lot of chlorine.

Mike.

 

[Texas Splash]

Mike, the duration of a SLAM Process varies from owner to owner. So much depends on the local conditions, severity of the algae, and effort of the owner via FC maintenance, pool cleaning, and inspecting. Our pools are about the same size, so I too would be concerned if it too two or more weeks to complete a SLAM, although I don't have to close each year. I suspect the following things are something you might consider if you haven't done so already:
1. Close as late as you can each winter, then open as early as you can each spring.
2. Deep clean the sand filter. If that hasn't been done for a season or two, it may help. Some do it every year as part of their opening routine.
3. Inspect, inspect, inspect. Many times what stalls a SLAM is that hidden jewel of algae. Either in hollow steps, ladders, behind the light (niche), or in the main drain.
4. Make sure your reagents are fresh.

From there it just takes time and consistency. Hopefully yours will wrap-up soon so you can enjoy the pool.

 

[mikefamig]

Mike, the duration of a SLAM Process varies from owner to owner. So much depends on the local conditions, severity of the algae, and effort of the owner via FC maintenance, pool cleaning, and inspecting. Our pools are about the same size, so I too would be concerned if it too two or more weeks to complete a SLAM, although I don't have to close each year. I suspect the following things are something you might consider if you haven't done so already:
1. Close as late as you can each winter, then open as early as you can each spring.
2. Deep clean the sand filter. If that hasn't been done for a season or two, it may help. Some do it every year as part of their opening routine.
3. Inspect, inspect, inspect. Many times what stalls a SLAM is that hidden jewel of algae. Either in hollow steps, ladders, behind the light (niche), or in the main drain.
4. Make sure your reagents are fresh.

From there it just takes time and consistency. Hopefully yours will wrap-up soon so you can enjoy the pool.

I did deep clean the filter when I opened and the reagents are new. The pool is a simple rectangle and the ladders are removed. We let the FC level slip a little once or twice but have been good about keeping it above shock level. I would feel better if I could hear that others in my area have the same thing going on in their pools. I have no idea what I am doing wrong and in the past couple of years it has done the same thing and eventually cleaned up.

 

[mikefamig]

I want to add that my winter cover is a Loop Loc safety cover that is a sieve. Everything goes through it and into the water in the off season. I understand that a solid cover keeps the water cleaner and maybe this is causing the long SLAM.

Mike.

 

[Texas Splash]

I want to add that my winter cover is a Loop Loc safety cover that is a sieve. Everything goes through it and into the water in the off season. I understand that a solid cover keeps the water cleaner and maybe this is causing the long SLAM.

That certainly doesn't help, and you lose some of the protection benefits of a solid cover for sure. I suspect you are blooming later than us down south, but out heavy pollen season always causes quite a stir. But from everything you describe with accurate, consistent testing and inspection of the pool itself, I think you're on the right track. About the only thing that may help you in this scenario is the close late/open early scenario just to try and cut-down on the length of time the pool is closed. Come Sept/Oct, get back with us on your closing techniques just to see if there's anything else chemically that may help delay the onset of algae in 2021.

 

[mikefamig]

For the sake of accuracy and so as not to mislead anyone else having a hard time cleaning up their pool water I need to make a correction to my original post.

It was May 23rd when I began the slam so it is not two weeks. It seems like a lifetime but it has been 10 days so far and hopefully I'm near the end. This procedure requires a lot of patience and faith in the science behind it.

Mike.

 

[mikefamig]

That certainly doesn't help, and you lose some of the protection benefits of a solid cover for sure. I suspect you are blooming later than us down south, but out heavy pollen season always causes quite a stir. But from everything you describe with accurate, consistent testing and inspection of the pool itself, I think you're on the right track. About the only thing that may help you in this scenario is the close late/open early scenario just to try and cut-down on the length of time the pool is closed. Come Sept/Oct, get back with us on your closing techniques just to see if there's anything else chemically that may help delay the onset of algae in 2021.

Good point about the closing technique. I didn't use any algaecide last closing, I just shocked it good and put the cover on.

Mike.

 

[mikefamig]

HJow much does PH affect the SLAM? It was good when I started the SLAM but I added about 5 lbs of baking soda mid SLAM when I noticed that my TA was only 60.

Mike.