A few questions for new pool owner

[Calgone18]

Hi,
I am a new pool owner. I have a salt water pool that is about 17000 gallons. The pool has been opened and chlorine is at zero as no chemicals have been added yet. Cyanuric acid is also at zero and pH is at 7.2. I used the pool math calculator and it says that to SLAM the pool I need about a gallon and 1/2 of liquid chlorine 12.5% to get me to a chlorine level of 10. Does that seem accurate? Also my pool guy has the pump set to 23 hours a day. Is that necessary or can I run a little less? Also can someone explain how to backwash a filter to me? I have a rather new Hayward DE filter. Thanks
James

 

[Texas Splash]

Welcome to TFP! So the pool was just opened meaning it already had standing water from last year correct? If so, the first question we ask is how does the water look? Is it crystal clear with no signs of algae? If not, then simply increase the CYA to 30 (for now) and increase the FC to about 5-7. Let it mix well all day and test the FC again later today to see how it's holding. If you lose a lot of FC, increase it again back to 5-7 and consider doing an Overnight Chlorine Loss Test to see if a SLAM Process is needed. Only after you know there is no algae should you increase the CYA to 70 for a salt pool. (Don't forget to update your signature).

Now if you already know a SLAM Process is needed, you'll add stabilizer for a CYA goal of 30 and increase the FC to "12" (SLAM level) and maintain that FC of 12 until you pass all 3 SLAM criteria. Test the FC as much as needed early-on to ensure the FC is holding well at 12. Consistency is key. Let us know if you have any questions. Good luck!