Shocking without knowing FC levels

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H

hausmann

Member
May 21, 2018
13
Kentucky
Pool Size
8500
Surface
Vinyl
Chlorine
Liquid Chlorine
Hi, new pool owner. To cut it short, I had absolutely no idea what I was getting into. The pool is a 24x52 Intex Metal Frame, round, 12k gallons. I also have the 2500gph sand filter (older model, got it second hand.) Took two weeks to get the land leveled! 4 attempts to fill the dang thing. Finally ended up being only a 1/2" off level. Anyways I'm finally to the point where I have to shock it. We filled the pool with pond water, so it was really, really brown and murky (see https://i.imgur.com/xo84plX.jpg) Been doing all this by the seat of my pants and learning as I go.

I started out by thinking all I needed was a shock, chlorine tabs, Ph control, and a stabilizer. So I did that. I used almost a whole bottle of Clorox Pool & Spa sanitizer (which is trichlor, roughly 3 pounds) and I added enough CYA to hit 30 PPM. Upon almost nothing changing in the water, I realized I needed to do some research.

Using CYA and trichlor is bad, okay, wasted a bit of money. I also backwashed the filter a few times to hopefully get rid of any undissolved CYA granules. I now realize I need regular (sodium/calcium) chlorine, CYA, and probably something for the alkalinity; for which I got baking soda. At this point I also realized the the 2-way Clorox brand test kit I bought is pretty much useless. My options are a bit limited due to my location (no pool stores nearby) but I found a 6-way liquid test kit made by hth from Walmart. The only issue is it doesn't do FC, just TC (via oto.) I tested my water last night and this is where it was at:

FC: ???
TC: 20 ppm (went dark orange, so off the chart. I mixed 1/4 pool water with 3/4 RO water and re-tested, got 5 ppm. Multiplied by 4 to get 20. Don't know if that is even accurate)
PH: 7.5 - raised from 7.2 with baking soda (confirmed with test kit and a calibrated Milwaukee PH controller)
CH: 80 ppm
CYA: 50 ppm (tested twice)
Alk: 120 ppm

I'm not able to source a test kit that does FC until Friday (ordered a Taylor kit off Amazon.) Last night the water looked pretty much how it did when I started, except I could see the bottom of the pool (barely.) It also had a very, very strong chlorine odor, which from my understanding is combined chlorine? I read about breaking point chlorination, and my gist of it is that you keep adding chlorine until all CC is dealt with and all organic matter is gone. So CC does dissolve when there is enough FC, correct?

Armed with that information I went out and got 3 128oz 10% sodium hypochlorite jugs and added them to the water over the span of about 8 hours or so. I read about mustard algae, and I suspect that's what I'm dealing with based on observation, there's tiny bits of black/brownish algae floating everywhere. And the fact that I pulled that water from a murky, stagnant pond. By the end of it, I started to smell less and less chlorine. I also got some hth chlorine pucks (without CYA, they're calcium hypochlorite 65%) and set 4 of them in the skimmer basket and went to sleep. I also added 3/4 cup of DE to my sand filter via the skimmer, until the PSI went up 1 point, as suggested in the tutorial section.

Today the water looks much better, but it's still murky. See https://i.imgur.com/TzFKKM4.jpg and https://i.imgur.com/bYVz8rO.jpg. Am I on the right track here? Or am I wasting my time and should I wait until I can test the FC levels and go from there?

Thanks for reading!
 
Thanks for the quick reply!

Since I'm not able to check the FC at the moment, would it be best to stagger the addition of chlorine every few hours or so until clear as I've been doing? Or just add a bunch all at once and monitor the result?
 
If you dump in a whole bunch of chlorine at once you risk bleaching your liner. We don't believe in dumping in chlorine all at once to reach "breakpoint chlorination" We follow the SLAM Process method with requires frequent accurate FC tests. Until your kit arrives you won't know how high the FC and CC are, or how high you need the FC to hit slam level.
 
Thanks for the input everyone. I have decided to be patient and wait until my kit shows up on Friday. :rolleyes:

I have left the chlorine pucks in the pump basket in the meantime, so hopefully the water won't get worse.
 
hausmann said:
Thanks for the input everyone. I have decided to be patient and wait until my kit shows up on Friday. :rolleyes:

I have left the chlorine pucks in the pump basket in the meantime, so hopefully the water won't get worse.
Click to expand...
Please don't put pucks in the skimmer basket. When the pump is not running, they continue to dissolve and make the water very acidic. This can damage your equipment. If you are going to use pucks, and we normally advise against them as they raise your CYA to undesirable levels, at least put them in a floating dispenser.
 
jeffchap said:
Please don't put pucks in the skimmer basket. When the pump is not running, they continue to dissolve and make the water very acidic. This can damage your equipment. If you are going to use pucks, and we normally advise against them as they raise your CYA to undesirable levels, at least put them in a floating dispenser.
Click to expand...

Gotcha! I made sure to get a brand without CYA (hth brand, all I could source around here) and I've left the filter going 24/7. I'll be sure to remove them once my water is clear and I'm not leaving the filter on all the time. They are calcium hypochlorite, but with my low CH levels I assume they won't pose a long-term risk.

The water is looking much, much better today (pic yikes the wrinkles) so I suppose I'll top it off with the hose and vacuum to waste to get the gunk out of the bottom. I tried vacuuming to filter, but I'm having issues with air in the filter/pump lines and every time I bleed the air the filter shoots out some nasty brown water - only when the vacuum is hooked up, so it's odd to me, not to mention I get very, very little suction through the vacuum (it's a basic Intex vaccum.)

During normal operation the return has all kinds of air coming out of it (pic 1 and pic 2 - the air release valve broke. We replaced it with PVC... Hah) and I can open the air release valve to fix it, but the air comes back within 30 minutes. Checked and lubed the gaskets on the pump basket, sand vessel, and the hosing on both sides. There actually seems to be a small leak in the pump basket housing... I can see water slowly dripping out. If that doesn't solve the problem I guess I'll take apart the 6-way valve and check it today. Fun!
 
Hey, just an update, got my Taylor FAS-DPD test kit in... And here's my numbers:

PH: 7.2
CH: 100 ppm
TA: 120 ppm
CYA: 30 ppm (is a 20 ppm drop in four days normal? I have backwashed the filter a few times since the first test)
CC: 2 ppm
FC: 14 ppm

The chlorine/CYA chart shows I should have a level of 12 ppm, so I guess I did alright! Also fixed the air in my pump and filter lines, the pump basket housing had a sizable crack, which I fixed with JB Weld. I'm going to end up buying a new pump/filter combo anyways, I suppose. They're relatively cheap. But for now it's working like a beauty, no air whatsoever.

So I should continue the SLAM until my CC is 0.5 or less, keep vacuuming, do an OCLT, wait for my chlorine levels to hit the target according to the chart... And I can finally swim? :eek: Not sure how the water looks at the moment as it's dark out, but it looked very clear via my flashlight. Hoping I don't have issues with cloudyness.
 

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The pool is safe to swim in when the FC is between minimum and SLAM level. You also need to be able to see the bottom of the deep end.
 
How intriguing that you started with pond water! Keep up the SLAM, can’t wait to see it clear!
 
Thanks everyone! FC drifted to 10 ppm since my last post, and CC is now 0.5 ppm. The water is nearly 100% clear. Just have some gunk I have to get out of the bottom with the vacuum. I'm calling it a success! Here's a pic.

kellyfair said:
How intriguing that you started with pond water! Keep up the SLAM, can’t wait to see it clear!
Click to expand...

I was a bit apprehensive about it but my options were pretty limited. The only way on to our property is a rickety 3-ton limit bridge... So a delivery was pretty much a no-go, and we have well water, which is very, very high in iron. Didn't want to deal with that, so I opted to use our pond. Lol
 
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