I didn't have this issue last year because by the time I found you guys I had already put like 11tybillion pounds of shock in the pool, and cya didn't have to be adjusted. This year it is at 0, and I have to SLAM. I noticed that I'm supposed to run the pump for 24 hours, and I can't do that because the pump basket clogs up within an hour of running, and it also says not to backwash, which means I can't vacuum to waste, right? So what do I do here?!?
Slow down... breathe....
For starters, if the pool is a green sludgy mess and all your CYA disappeared, it may have broken down over the winter into Ammonia. More on that later.
Second, if you do add CYA using the sock method we recommend, you can backwash to your heart's content because the granules
aren't in the filter to get flushed away.
Third, vacuum to waste takes the filter right out of the system. The water enters the pump, hits the multiport valve, and gets sent out the backwash pipe/hose. If the pump basket loads up, it's not a big deal to knock it clean. Or buy a leaf canister that sits inline in the vacuum hose and catches that stuff before it gets to the pump. You don't have to worry about clogging a pipe underground that way, either.
Back to Ammonia....
1. Begin a SLAM and dose FC up to SLAM level. Do not add additional CYA at this point. With zero CYA, SLAM level is 10 FC. Make a lap around the pool with the brush to get it all mixed really well.
2. Retest FC at 10-minute intervals.
a. If FC loss is greater than 50%,
Hold on right here. Post the FC & CC results in this thread. Someone can tell you if it looks like Ammonia or not, and if it's going to be more cost-effective to drain and refill than to treat it. If you DO have Ammonia, I'd lean towards draining, since you will be losing so much water already vacuuming to waste. It will take massive amounts of bleach to neutralize Ammonia.
We now return to the cut-n-paste Ammonia Treatment. add FC to bring back up to SLAM level and continue retesting FC @ 10-minute intervals.
b. IF FC loss is 50% or less, add FC to bring back up to SLAM level. Go to Step 3.
3. If CYA is below 30 ppm, add enough CYA to bring level up to 30 ppm.
4. Continue SLAM as directed in the SLAM article until the SLAM Criteria of Done are met. Test as directed in the SLAM article - no longer need to test FC at 10 minute increments at this point.