PoolMath says to use 3 gallons of 12.5% liquid pool shock for a SLAM, but the SLAM check list says I'll need at least 15 gallons or more for a 30,000 gallon pool. No FC showing, PH at 7.1, TA at 90, CYA at 30. Water is clean, but green; can't see the main drain, but bottom easily visible in shallow end. How to procede? Thanks. HarrisonJ
Water Chemistry
- Thread starter HarrisonJ
- Start date
The 3 gallons is just to start the SLAM. SLAM is an ongoing process that will take some time depending on how bad the water is. There’s no definitive way to know if it’ll take 5 gallons total or 15 gallons total. Don’t buy too much because it doesn’t last forever even when stored in a cool place.
- Jun 24, 2021
- 17,264
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
The 15 gallons is to purchase. After you add the 3 gallons to get to slam level, algae will consume some of that FC. After a couple hours and you test FC again, you will have to add more to get back to SLAM level FC. It is a process of testing and replacing FC to slam level multiple times until you meet the exit criteria.
After slam, if you have some left, you can use it for daily chlorination or take it back.
After slam, if you have some left, you can use it for daily chlorination or take it back.
Your pool will go through the better part of a gallon per day once it warms up with 30k gallons. I wouldn't worry about buying too many.
Thanks to Bperry, Poolstored, and Newdude. I wrote in more detail how this year's opening has proceeded, and my assumption:
After 33 years with out pool, I’m finally onto Trouble Free Pool. I started the SLAM process 10 days ago, but had added 3 quarts of Menards Algae X-Tra Algaecide the day before. The next day I shocked the 30,000 gallon pool with 4 gallons of 12.5% pool chlorine bringing the FC to about 15. Each morning for a few days following, FC was at 9. One gallon liquid chlorine brought it up to 12. I did that for 4 days, then started adding 2 gallons a day. I thought the CYA was about 30, but that was according to HACH Aquachek 7 strips. My Taylor K-2005 kit says it’s more like 60. Now the FC is 15 each morning, but I still can’t see the bottom in the deep (8 ft.) end, even though the water looks clean in the shallow end. I’m assuming I should just keep adding liquid chlorine to keep FC around 15-18, and trust the water will eventually clear? Thanks again. H.
After 33 years with out pool, I’m finally onto Trouble Free Pool. I started the SLAM process 10 days ago, but had added 3 quarts of Menards Algae X-Tra Algaecide the day before. The next day I shocked the 30,000 gallon pool with 4 gallons of 12.5% pool chlorine bringing the FC to about 15. Each morning for a few days following, FC was at 9. One gallon liquid chlorine brought it up to 12. I did that for 4 days, then started adding 2 gallons a day. I thought the CYA was about 30, but that was according to HACH Aquachek 7 strips. My Taylor K-2005 kit says it’s more like 60. Now the FC is 15 each morning, but I still can’t see the bottom in the deep (8 ft.) end, even though the water looks clean in the shallow end. I’m assuming I should just keep adding liquid chlorine to keep FC around 15-18, and trust the water will eventually clear? Thanks again. H.
Slam for 60 CYA is 24 FC. Bump it back to 24 whenever it dips, no more than every 2 hours. If its holding most of the FC 2 hours later, go to 3 hours until that holds well, then 4, 6, etc. It will tell you when it needs more, if you listen.
