Why bring up CYA for initial SLAM?

[doncaruana]

I've got a saltwater pool and I'm just wondering why I need to bring up the CYA level before the initial SLAM (cover with drain panel, water is green from the winter). Understanding there will be loss during the day from sunlight, but there won't be at night, which is kind of the crucial test (OCLT) anyway. Seems like I could get things more under control during or before bringing up CYA (which is a slow process without liquid CYA, which is expensive).

I get it during the season, but at open, especially when it means putting 4 gallons of 12.5% bleach in, I don't quite follow the need. Educate me, please.

 

[Texas Splash]

I don't see your pool info in your signature, but let's say fro example you have a vinyl pool. If you had no CYA in the water, the chlorine added is exponentially strong and much too harsh for the liner. So it's not just about the FC exposed to the sunlight, it's also about controlling the chlorine itself. Also remember that in a SLAM, many pool owners get into the pool to perform maintenance (scrubbing, inspecting, etc). If there was no CYA, they could not do that. So having a minimum CYA of 30 is ideal, not only for basic buffering protection from the chlorine, but minimal CYA level requires a lower FC SLAM level.

 

[proavia]

Having a CYA level of around 30 will help prevent the FC from burning off in the sunlight within a few hours. Start granular CYA dissolving now. And start the SLAM Process based on the CYA level you plan to attain by that addition. No need to add liquid stabilizer (liquid gold) - use granular.

Do you have current test results? If you share your PoolMath logs we could see them there.

 

[Donldson]

I think you are severely underestimating just how much chlorine will burn off in the sunlight without any CYA. All of it. Within a few hours on a nice sunny day. And algae does love chlorine-free water to grow in.

So not only for the reasons Pat mentions, but also it will take longer and you will burn through more chlorine attempting to do it without CYA.

 

[mguzzy]

What is your current CYA and other chem levels.. then we can talk specifics

 

[doncaruana]

What is your current CYA and other chem levels.. then we can talk specifics

I just pulled the cover off - don't have levels yet. I know the drill in general. I expect to have no CYA and no chlorine in the pool, unfortunately. Usually takes a few days, hopefully not too bad this year. I'll probably runn in parallel (CYA and bleach at the same time) and not wait for CYA.

 

[mguzzy]

Oh yeah I got you.. you have to get some Cl in there before things get worse.. and throw some CYA in there to start protecting the CL from the sun. eventually it all comes together.

 

[doncaruana]

Well this is awesome...the barrel nut for the band on my cartridge filter just stripped. Fabulous. Ugh. Definitely need to get things rolling now, since I can't even fire up the SWG to help out nor get water flowing.