SLAMing with a DE filter - when/how often to backwash and clean filter grids?

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Added 1 gallon of 10% at 10AM.

7:50PM FC is 28.5. Hoping for some improvement in Day 4. I tried running the filter for an hour around 3PM, backwashed and recharged it with cellulose fiber. In the hour the pressure went from 20 to 30. Backwashed again and switched back to recirculate around 4PM.

At some point during SLAM will the water clear up on it's own so that I can see the bottom and vacuum the dead algae? Or will I have to vacuum blind (to waste) before the water clears up? I'm nervous to vacuum because I know there must be some leaves lurking on the floor of the pool.

Thank you so much everyone for your help! Without this site I would be hopeless!
 
That cloudiness IS dead algae. You can vacuum to filter or waste. Yes, it will clog the filter quick, but that's the penalty for the excellent filtration. If the water is grey-blue now and the chlorine thirst has slowed, you really have no choice but to vacuum it all up and start filtering it out.
 
Richard320 said:
That cloudiness IS dead algae. You can vacuum to filter or waste. Yes, it will clog the filter quick, but that's the penalty for the excellent filtration. If the water is grey-blue now and the chlorine thirst has slowed, you really have no choice but to vacuum it all up and start filtering it out.
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OK thank you Richard and Tim! I think the only option is vacuuming to waste and adding new water (and diluting the chlorine level). If I recharge the filter with cellulose fiber, that only buys me an hour before the pressure raises 10psi and I have to backwash/recharge it again. I can't replace it at that rate because it's just too expensive for the replacement cellulose fiber.

Day 4
7:30AM FC is 25. FC only dropped 3.5 in the past 12 hours. The water is a lighter shade of green/gray-ish. Not quite cloudy blue but not dark green.

I have to work today and won't be home until late, so vacuuming isn't an option. Best I can do today is keep the pool at SLAM level.
 
Separate question - but I was instructed by an admin to keep all questions in this one thread:

My pool has two pairs of skimmers/returns but only one pair works. Years ago we had someone come out and test the pressure on both lines and there was no pressure on one of them. The guy told us it would be very expensive to fix (over $1,000) and our pool is OK with just one skimmer and one return.

We keep the one skimmer/return plugged all year but dirt/debris does tend to collect in the non-functioning skimmer area.

Is there a way I can seal off the non-functioning skimmer area from the rest of the pool so that that water doesn't mix with the rest of the pool water? A plate of some sort?
 
Is there a way I can seal off the non-functioning skimmer area from the rest of the pool so that that water doesn't mix with the rest of the pool water? A plate of some sort?
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There sure are. I asked my best friend "Google" and quickly found several options like this one:
Skimmer Plug
 
Thank you to you (and your friend)! :D Sorry I am completely clueless with all of this. I'm learning so much here, I've been on this forum non-stop for days. Thank you Texas for helping out!

FC was 22 at 5:30PM, much bigger drop off than yesterday (I'm assuming because today was a sunny day). I'm going to add another gallon of 10% and check before bed.

Day 5
9:30AM FC was 23.5. Added another 1 gallon of 10%. Pool water looks about the same as on Day 2-3, but I haven't been able to vacuum so we're stuck for now. Hope to be able to do some serious work this weekend.
 
Day 7

We've had a breakthrough! We've changed from green water to cloudy blue! Although it's still very cloudy, I can almost see the bottom of the pool in the shallow end. I deep cleaned my DE filter yesterday. Prior to cleaning, the filter pressure was raising from 22 psi to 30 psi within 30 minutes of backwashing and recharging. After cleaning each of the grids, the manifold, and the entire inside of the DE filter, then recharging, the PSI stuck at 19 for hours and took nearly 24 hours to raise to 24 psi. It was the first time I could leave the filter on "filter" for an extended period during this SLAM process. I've had it locked on recirculate or vacuum the previous 6 days. I've vacuumed each of the past 3 days. I anticipate that the water will gradually start to clear up.

I have noticed some concerning shadows around the perimiter of the pool floor near the base of the wall in the shallow end. I really hope that this green swamp hasn't stained the vinyl liner. I'll get a better view in the coming days and will report back with progress.

Thank you so much for all of your help! The pool is definitely moving in the right direction. Here's are some photos showing the difference between last Sunday and this Sunday: 6_4_17.jpg05_28_17_0747.jpg
 

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Yes CYA was 60 when I started, but I've been vaccuming to waste and backwashing a good amount of water and replacing the water. I haven't tested CYA since the beginning of the SLAM. Is now a good time to test again? Or should I just wait until I get through the SLAM?
 
Week 2 of SLAM - still maintaining above a FC of 24. I lose about 4 FC overnight. Water is pretty clear and filter pressure has stabilized for 2 days at 21 psi. I add 2 gallons of chlorine per day - 1 in the AM, 1 in the PM.
 
DAY 12 of SLAM
FC was 22 last night at around 11:30PM. Water was clear and not much to vacuum. I can see clearly to the bottom of the pool! :D I thought I'd try OCLT, so I didn't add any more chlorine. I checked again at 6:30AM and FC was 21.5. We may have passed OCLT on the first try! It was a cold, night (in the 40's) so I'm going to try again tonight. I've also been using the K-2006 test with a 10 ml sample to conserve reagent testing drops. I'm going to increase the sample to 25 ml tonight to get a more precise reading.

Question: Is water temperature a factor at all in the OCLT test? I assume it's irrelevant, but just wanted to check to be sure because the temperature was cold last night.

We've made it to clear water and I can see the light at the end of the tunnel! THANK YOU everyone on this board for your help. Although I believe I've bleached the liner slightly (it's lighter than it was last year), I think the algae is gone (fingers crossed). I will stay on top of testing this year so I never have to do this again. If we pass OCLT tonight again, I'm going to let the FC drift down to the acceptable level according to the charts on this site.

Here are some photos of the progress:

2017_05_28.jpg
2017_05_29.jpg
2017_06_04.jpg
2017_06_08.jpg
 
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