Slam works period. Once you have the variables dialed in like pool volume, pool math entries, chlorine strength and following the slam process to the letter.
Yes definitely making harder. Last year was easy peasy. I will test after work today and post results. Ben had a good point about pool volume. Place I got pool says ~25400. Pool calculator online has it ~29k. 18x36 IG, 4' shallow 8' deep. BTW all you guys are awesome.With all due respect you seem to be making this harder than it needs to be.
Let's start over by posting your current test results then tell us how much & the percentage of chlorine you added. 15 minutes later tell us the new FC level.