Opening pool, 18 days into SLAM, considering but nervous about adding DE

canjones

Well-known member
Aug 27, 2016
107
Duncanville, TX
I have been in SLAM mode since the end of Spring Break. I wasted a few days because my CYA was low. Now that I have that under control I am still dealing with cloudy water. I was thinking about adding DE to my filter but I have never done that before. I read the directions on TFP. But a post on Amazon about using DE in a sand filter made me nervous. Also, I really don't want to buy that huge expensive bag in the pool store so I would like some recommendations. I posted pics of DE I was considering.

My test results this afternoon
FC 15 (added chlorine to raise to 18)
CC 2
CYA 50
 

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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,405
Laughlin, NV
Nothing to be nervous about. You need to be able to babysit the filter when you do it. Add a 1/2 cup at a time and stop when you see 1 psi rise. Then check the filter every 10-15 minutes and backwash when the pressure rises to 20% over clean pressure.

Your SLAM level FC is 20 ppm with a CYA of 50.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
41,361
Tallahassee, FL
Marty is so right! It is no big deal so long as you can babysit it the first few times you add it. Once you know how much YOUR filter likes it will be a breeze to use and your water will clear up even faster!!

Kim:kim:
 

canjones

Well-known member
Aug 27, 2016
107
Duncanville, TX
Nothing to be nervous about. You need to be able to babysit the filter when you do it. Add a 1/2 cup at a time and stop when you see 1 psi rise. Then check the filter every 10-15 minutes and backwash when the pressure rises to 20% over clean pressure.

Your SLAM level FC is 20 ppm with a CYA of 50.
I have noticed that something is going on with the Pool Math App. It has been saying that SLAM is 18 with CYA 50. I went in and cleared everything and now it says to SLAM at 20. So, now another week wasted!
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,405
Laughlin, NV
I have noticed that something is going on with the Pool Math App. It has been saying that SLAM is 18 with CYA 50. I went in and cleared everything and now it says to SLAM at 20. So, now another week wasted!
That is odd about the app. I test things on it continually and have not seen that.

No waste. Just takes a bit longer at a lower FC. Start using the 20 ppm FC and things are all good.
 
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Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,470
Bedford, TX
Jones,

You should SLAM when the cost of bleach is less than water... I live in the DFW area and can fill my 17K pool for about $50 bucks... If I didn't see a drastic difference in the first couple of days, I would be draining it and starting over...

Jim R.
 

canjones

Well-known member
Aug 27, 2016
107
Duncanville, TX
Jones,

You should SLAM when the cost of bleach is less than water... I live in the DFW area and can fill my 17K pool for about $50 bucks... If I didn't see a drastic difference in the first couple of days, I would be draining it and starting over...

Jim R.
Interesting. I never thought about that. Tell me more. So it's okay for me to drain with a vinyl lining? I would have to use my water hose to siphon.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
41,361
Tallahassee, FL
DE-I get it from Lowes. I still have most of the box I bought long ago but it does not take up much room so no biggy for me to have it around.

Kim:kim:
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,470
Bedford, TX
Jones,

I really do not know much about above ground pools, but assume it was empty when you filled it up the first time... :)

And depending on what is going on you might not need to drain it all.. I went back and looked and your CYA is only 50, so your SLAM should not be this hard.. How sure are you that your CYA is actually 50?

Are you just dumping in chlorine once a day or are you maintaining a shock FC all the time?

@mknauss ... any reason not to drain and start over? Or maybe drain 75%??

Thanks,

Jim R.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,405
Laughlin, NV
No real reason I see for not draining if that is desired. You would need to leave 18 inches or so of water in the pool to keep the liner from shifting.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,470
Bedford, TX
Jones,

Once you fill it back up you will still have to finish your SLAM, but that should be very quick and shouldn't take a lot of chlorine..

Jim R.
 
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cfherrman

TFP Guide
May 10, 2017
2,377
Hays, Kansas
I used the hth de filter aid from Walmart. My pump is small so I do have to babysit it and I only use it on the weekends. In a slam you will need to be around for it.