Algae and Filter is Offline

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Boy, the FC really drops fast! Since this morning I've put in 17.5 gallons of bleach. Is that normal?

My readings at 12:30 were:
FC 18
CC 1.0

Per Pool Math, I added 2 gallons (a little more than suggested).

By 3:30, it had dropped:
FC 14
CC 0

Added 4 gallons & brushed.

At 4:30pm:
FC 23.5
CC .5

My target is FC 20. Hopefully it will level off before its too dark.

Question: Those bubbles forming on the surface...that's the bleach killing the algae, right?

Thanks everyone for your awesome input!
 
Eric, can you confirm please what type and percentage bleach you are using? On the Poolmath Calculator, when I enter your last test and 4-gal additions between 3:30 and 4:30, the 4 gallons should take the FC from 14 to 21 if it was 8.25% bleach. 10% bleach would take it to about 22, but you recorded 23.5. So I was curious. The bubbling is also interesting. Is the bleach regular (plain) and not anything added like scented or splashless?
 
Hi, I have been using 8.25% bleach from Target (Up & Up, for $3/gallon) with dates around "16 090". It says "concentrated"; I saw the lavendar and splashless jugs but didn't get those.

My yesterday 4:30pm FC held at 23.5 in the evening. I poured in a gallon last night because I didn't want it to drop below 20 overnight, and had a reading of 23.5 this morning. CC at 0.

The bubbling appears mostly when I brush. There's maybe a few dozen across the surface, more in the shallow end where I have poor circulation. Bubbles stay for a couple hours. When I skim them, they're clear and a little foamy in the net.

I have been at shock level about 24 hours now, with one or two brief dips. I no longer have the green cloud stirring up when I brush (2x since yesterday AM) and really cannot see any more signs of algae. However, the water is cloudy and I certainly cannot see the main drain at 10 feet. I backwashed/rinsed last night.

So, do I just hang tight and wait for the filter to do its thing? (I haven't deep cleaned it, but looked in it recently and the top looked like new.) Thanks!
 
Yes Eric, keep pressing-on with what you are doing. As for the bubbling .... that has me curious still. Once your SLAM is complete and you can see into the pool really well, we might look closely at your CH (calcium) levels. But we can discuss that after the SLAM. Keep at it!
 
That could be part of the bubbling/foaming issue.... "maybe". Either way, your CH is very low for a plaster pool. You'll want to increase it as follows:
Calcium hardness can be raised with calcium chloride or calcium chloride dihydrate. They are available in some areas as Peladow, Dowflake, Tetra Flake, or Tetra 94, often sold as a deicer by hardware stores, and some big box stores, in colder climates. Pool stores will carry either calcium chloride or calcium chloride dihydrate under a variety of names, including Hardness Plus, Balance Pak 300, Calcium Hardness Increaser, etc. Calcium products should be spread across the surface of the deep end of the pool.
Click to expand...

Your minimum CH level is 250 ppm
 
Thanks Pat. According to PoolMath, I would need to add 69lbs or 92lbs of either item. That's alot of stuff! I'll check the hardware stores in town, because this will be in the pool section (no one retails deicer here...I think).
Also, I have been told twice in the last few months that no one here (Hawaii) bothers with CH in their pools. I don't know why.
Finally, will large amounts of calcium chloride or calcium chloride dihydrate affect any other levels, because that is a huge jump (150%) from 100 to 250?
 
No raising CH will not impact other levels. Yeah, probably no deicer available in Hawaii. LOL! I don't know why nobody would measure or adjust CH there. With CH that low you are at risk of your pool dissolving CH from your plaster and etching/pitting it leading to premature failure.
 
Does anyone happen to know the margin of error on the 5ml version of the chlorine test?

It will be a few days before my R-0871 resupply arrives and I'm testing 4-5 times a day. My target is FC of 20.

I'm starting day 4 of my SLAM, and things are better (no more green stuff...adding much less bleach) but far from done. It is still cloudy. My robo-vac at 10' depth is just a dark blob. FC fell below 20 a couple times, but only for a few hours I think and never below 16. Did that set me back??

I brush thoroughly 2x/day, have vacuumed twice, and backwashed/rinsed twice, after each adding about a cup of DE to skimmer. No more green cloud when brushing, though there is a faint grey cloud when brushing (wouldn't notice without looking closely).

Is there anything else, or do I just need to be more patient? (Bummed...because we have guests coming over tomorrow)
 

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I can make out the main drain. Does that count?
FC is actually over my slam level (25, instead of 20...overcompensated last night). If I get in the water, will my skin peel off? Or, do I just plan on my red shorts going pink?
 
Seeing the main drain is good. As for the FC, I wouldn't wear my finest swimwear that's for sure. But swimmers might experience some irritation as well. All I can say is by TFP guidelines, if you're over your SLAM level, you shouldn't be in the water. :)
 
I have a couple questions on this Day 7 of my SLAM. First, some background...I did my first OCLT last night:

Sunday, 7:30pm (late dusk)
FC 21.5 (Shock target of 20)
CC 0

Monday, 5:30am (barely dawn)
FC 21.5 (whoop!!)
CC 0 (whoop!!)

But...still murky! Ugh! I go back at 9:00am, FC holding well @ 21.0 (UV burn-off? Partly sunny) & CC @ 0. A cup of DE has been in since the afternoon prior.

I have a little more time at 9:00am, so I do a long backwash/rinse, then set to recirc and pop the lid off the filter (valve is side mount, so no plumbing on lid). I unscrew plug to drain down some, rubber-band a baggie on the top lateral, and stick my hand down into the sand. I expect to feel crud, but, only pure sand do I feel. I wiggle my fingers around the rim of sand, move some around in the middle. No crud. I put the garden hose in, dipping into the sand in the middle and edges, water begins to overflow. Expecting to see crud come out, it is just nice clear water. I do the hose thing couple more minutes, dipping down and around, and no change, only clean water coming out. I'm running short on time and decide staying on the task won't give me any better results, so I button everything back up, do a long backwash/filter, and decide I need to query the Forum. There was maybe a 1 psi decrease from the prior post-backwash psi, so maybe it made some difference with the hose in the filter.

Question 1: Is the murkiness dead algae?

My filter sand seems clean, and I have been putting DE into skimmer (with socks on the baskets) following every backwash/rinse for the last several days with pump going 24/7 this entire SLAM. My shallow to about 7' is clear as I can see a couple gravel I missed the day prior. But, I can see the main drain's vents only with the pump off (i.e., no ripples from waterfall return). Otherwise, with waterfall spilling in, I can see only a white item (because I know where to look). Hopefully there will be an improvement tomorrow.


Now, my second issue. Since I didn't pass all 3 criteria, at 2:00pm I checked levels:
FC 17
CC 0
CYA 50

I pour in 2 gallons of 8.25% to get back to FC of 20. But now I'm calculating in my head: FC dropped by 4 ppm in 5 hours on a cloudy morning with showers, and now the sun is out and may stay out for another 4 hours.

Assumption: If FC stayed steady over night, then this morning's FC drop is from the sun.

Question 2: Will my FC always drop 3-4 ppm, each day, when I'm post-SLAM? Or, is this drop a result of my other levels?

Here's pre-SLAM levels last week:
FC 3
CC 0
pH 7.6
TA 70
CH 100
CYA 50

Maybe this is why the prior owner used 3" tabs...cheaper and easier to use for a pool this size? Hard to imagine going through 14 gallon jugs every week (vs. 4 tabs/week).
 
I think you are doing a great job in all areas. You're not describing anything off the charts odd, just a little more patience perhaps. That's why the 3 SLAM criteria. An FC drop of 2-4 ppm during the day is relatively acceptable. Anything over 4 ppm and we start to wonder what's going on. It's good you checked the filter again and are trying the DE trick. Still, filtering-out algae can take a bit of time. You do have a big pool. :) We see a lot of 15-30Ks here, but when you start talking 50K, you almost need a canoe. :swim: I would maintain what you're doing, of course continue the sweeping/scrubbing around the pool, and ensure there are no final hiding spots for algae. We'll watch your updates, and if things don't change soon, we'll bring-in the Calvary to ensure we aren't missing something odd.
 
Awesome! Thanks for the support. Canoe races!....Great idea for our next pool party.

I was close to giving in. I have bottles of floc and clarifier that I moved from the back of the shelf to the front this morning, wanting to speed this up. So, I should hold off on those, and give the filter more time??

I'll stick to the BBB method as long as I can, but, if 4 ppm a day FC loss is acceptable, that's 2+ gallons every day. 2 ppm loss a day would be more manageable for me, bleach-wise. But, for now, I want to get that water sparkly, levels balanced, CH up, and catch up on some fun. Then see what the loss rate looks like.
 
Yeah, I would hold-off on the floc and clarifier. I know they can be temping, but they can also cause other problems later. You started your SLAM on Apr 28th, so it's been a little over a week. Most SLAMs take a solid week or two, so you are probably close. Seeing that you passed an OCLT, it might all boil-down to filtration now. Let's see how thing look by this evening and go from there.
 

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