Only 2.5 days of slamming is not nearly long enough to worry about clarifiers. All you need is chlorine and time.
Clarifier is a bandaid that gums up your filter & makes things look ok when they are not
Continue with slam
For a successful SLAM Process
you need to continue to MAINTAIN Slam level fc for your cya until you meet ALL 3 end of slam criteria-
You are done when:
CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
the water is clear.
(Crystal Clear w/no algae dead or alive)
*Check & scrub every nook & cranny where algae may hide (light niches, steps, drain covers, ladder handrails, skimmer throats/weirs, etc.)
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine)
*Backwash/clean filter when pressure rises 25%over clean pressure.