Sand filters are the slowest to clear so patience is key. Keep with slam &
Do ALL the things

*Check & scrub every nook & cranny where algae may hide {light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.
*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.
You are done when:

CC is 0.5 or lower;

You pass an
Overnight Chlorine Loss Test
AND

The water is clear.
(Crystal Clear w/no algae dead or alive)
To help the sand filter grab more of the smaller particles you can add a little
pool grade DE when you’re around to babysit & backwash as it makes the pressure rise quickly.
A clean pool filter will increase the efficiency of your pool! ... your filter are to backwash it, clean the manifolds and grids, and add new DE.
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