Taking the Plunge (literally and figuratively) with My Pea-Green Pool

cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
Yeah, I ended up using a plastic one.

I have 31.45% muriatic acid. The poolmath app sez 28 oz, so that's what I added. I waited about an hour, then added the chlorinated liquid. Because of my CYA and FC numbers, it recommended a shock value of 20. The poolmath app translates this into 3.5 gallons. So I just now dumped 3.5 gallons of 10% into the pool. I will be running my pump 24 hours and cleaning my filter as needed. And of course, I'll be skimming leaves and brushing the pool sides, and making sure that my Pool Vac XL remains free of leaf clogs -- or trying to, at least.

The article recommended adding the liquid close to an inlet. Well, my inlet is my Pool Vac XL, which is in constant motion. So what I did was add the liquid at four equally spaced points, two of which were located near water jets. So, I guess my next question is, how long should I wait before I take my first FC test?
 

see_feel

Silver Supporter
May 31, 2018
51
Arlington, Texas
You are on the right path and congratulations for now taking the steps to ridding yourself of this algae problem, pool services and trips to a pool store. Aside from maintaining your FC level during the SLAM, get as much organic matter out of the pool and brush, brush, brush. It will speed up the time to complete the SLAM. Looking forward to seeing those beautiful blue water pics!
 

cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
Heh, me too! When it comes to getting rid of the organic matter, that's probably gonna take a while. My pool vacs are the only things I have and they're running their discharge through the filter, so I've gotta stay on top of the filter too. I've done this before, though, when the pool was almost this full of organic material, and the key was just keeping the filter cleaned on a regular basis -- because that Pool Vac XL slows way down when the filter starts getting a pretty good coating of schmutz on it. Too bad, really, because that's when a filter is doing its best filtration, ya know.

Years ago, the company I worked for sent me to a solids-liquids separations class. It was kinda interesting, but none of it was applicable to the way we ran our operation. But I still remember stuff from the class. Like with gravel bed filtration systems, for example, they begin to work really well once they've formed a layer of organic material that actually aids in the filtration process. And this layer of organic material is called schmutzdeka -- there's a good old Germanic word for ya. A deck of schmutz. I'll never forget that part of the lecture on that day. Heh. So, whenever my cartridge filter's got a good coating of organic material on it, I can't help but think of schmutzdeka and sometimes I wish I didn't have to clean the filter, but if I want that little bot to run, it needs the suction that the organic material is choking off. Oh well. But I think a decent compromise is to let the bot run until it's becoming noticeably lethargic. This tells me the filter has a good buildup of stuff so some good filtration has been going on for a while at least before it's time for another cleaning.

Oh, almost forgot. I took another reading after another two hours had elapsed. FCs are still 22.
 

cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
As of 7pm, FCs finally began to drop. They were 19, so I added 26 oz of liquid chlorine as per the poolmath app.

Do I do the regular set of TF-100 tests when I SLAM, and if so, what sort of interval would you suggest?
 

Fast7

Well-known member
Aug 8, 2018
65
Plainfield, IL
Do I do the regular set of TF-100 tests when I SLAM, and if so, what sort of interval would you suggest?
No, pH test is invalid with FC over 10 and TA, CH & CYA shouldn't change unless you do partial drain/refill.

The article recommended adding the liquid close to an inlet. Well, my inlet is my Pool Vac XL, which is in constant motion. So what I did was add the liquid at four equally spaced points, two of which were located near water jets.
This statement isn't correct. It is recommended to pour liquid in front of return, not inlet. You want to add any chemicals in a way they will be distributed in a pool as quick as possible. In front of return jets is best way.
 

cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
Okay, I must have misread. But ultimately I think my choices worked okay.

Latest FC numbers, taken at about midnight -- 21 ppm. Next test will probably be around 7am.
 

cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
This morning's test, taken at 7am: 22.5 ppm. Should I be concerned at all that my FCs have stayed essentially the same for the first day of the SLAM?

Flow rate looks okay, but I'm gonna go ahead and clean the filter in a little while.
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,295
Houston, Texas
Did you add any chlorine after last night's test? If not you have a testing error, the chlorine should go down or stay the same overnight, not go up. How is your pool looking now?
 

cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
I think it may have been the filter needing cleaning. I cleaned it right after posting my last message. Just tested the FCs again:

FC: 18.5 ppm
Added 38 oz of 10% bleach, as per the poolmath app.

The water is looking somewhat better. It's a bit more transparent and the green is definitely a lighter color. I'm gonna check the filter again this afternoon, after the Pool Vac has had time to scurry across the pool bottom a lot, vacuuming up algae and stuff. It leaves relatively clean paths behind itself so I'm reasonably confident that it's gonna be able to take care of the bottom -- and possibly even the sides. When it has sufficient suction, it will climb the sides quite often.

Reminds me, I need to brush the sides. Today, the weather is quite pleasant. Cloudy, 77F. Nice to have it so cool for a change.

Something just occurred to me -- what do you do after there's been a significant amount of rainfall? Every once in a while we'll get enough rain where it may add one or two inches to the depth of the pool. Should I retest for CYA after a heavy rainstorm?
There's no rain in the forecast for today, but the long range forecast is predicting several days of rain. So I may be having to deal with it toward the end of the SLAM.
 

mknauss

Mod Squad
TFP Expert
May 3, 2014
17,772
Laughlin, NV
Clean the filter when the pressure rises by 25% over the clean filter pressure.

CYA is rarely effected by rain fall. Unless you get a foot or more of rain.
 

cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
Mknauss, Your formula will be difficult to calculate with my filter. After I've cleaned it, when I first put the filter back into service, the pressure is zero -- or very close to it. And as you know, 25% of zero is zero. So what I do -- and this is borne out from experience -- is I clean the filter when the pressure across it is 14 psi. Using your math, that suggests an operating pressure of 11 psi. Anyway, at 14 psi, the Pool Vac is moving sluggishly and I know there's a good, but not excessive, coating of organic material. I've cleaned it before when the pressure was 10 psi and there just wasn't enough stuff built up on it yet to warrant cleaning. And, using your formula, I guess that makes sense.

Now, all this has led me to wonder if cartridge filters wear out, though. I'm sure they must. It seams to me that, after some time, the filtration media will break down in places and the filter won't work right at lower operating pressures. This filter will be 5 years old come this November, and I've been thinking it might be due for a change.

Tested today at 3:20pm. FC = 20 ppm. I didn't check the filter pressure, but the pool vac is still moving about well, so it isn't time to clean it again.
 
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cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
The gauge seems to work fine. It records low pressures. As I mentioned above, I suspect it might actually be the filter.

OK, well, I took care of that problem -- whether real or imagined. I just ordered a new filter cartridge.
 
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cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
No, it's a simple single-speed 1.5 hp motor driving the pump. I checked the pump pressure. It's at 11 psi right now, which tells me, based on the job the pool vac is doing and the decreasing turbidity of the water, that I'll probably have to clean the filter again some time tomorrow.

I just finished brushing the sides using my new Wall Whale brush. That thing is way cool and does a great job. One thing I noticed as I was scrubbing the sides was that I can see the brush all the way down to about 8 feet now. That's a definite improvement. The pool's green color -- keeping up with the mineral metaphor I've already used (jade green, that is), the color looks more like aventurine now, which is sort of a washed-out medium green color -- google it if you're not familiar with the mineral, you'll see what I'm talking about. It's lost that deep jade green hue.
 
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cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
This morning, I tested the pool water again. FC = 17. The PoolMath app recommended 77 oz of 10% bleach, which I added. That was about 7 am this morning. I began the SLAM almost 2 days ago -- 46 hours ago, to be exact. And during that time, the pool appearance has gone from a deep, jade-green hue to a very pale green one. Some pics, taken at 7 am this morning:

pool_light_algae_1a.jpgpool_light_algae_2a.jpgpool_light_algae_3a.jpgpool_light_algae_4a.jpg

The pool vac is still zipping along the bottom at a good clip, making sure that any organic matter won't be hanging around for very long, which tells me -- without having to look at the pressure gauge -- that the filter doesn't need to be cleaned yet.
 

cooltouch

Well-known member
Jun 4, 2018
74
Houston, Texas
The pool's water clarity is continuing to improve, little by little.

Tested FCs at 3:00 pm: 18 ppm. Added 51 oz of 10% chlorine as per the PoolMath app.

This is actually --surprisingly -- kind of fun.
 
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