High CYA, High Calcium, not sure what's next

Kconstan

Active member
Apr 25, 2020
33
Burbank, CA
Hi everyone-
This is a bit of a long story, but I'll try to cut to the chase. I was getting the pool ready for the season back in April and was struggling to keep up with the algae growth. I found that when I cleaned my filter and re-charged the DE, most of it was getting dumped back into the pool. That led to discovering that the filter had a cracked manifold. I replaced the manifold, and now the DE stays where its supposed to, but I was still struggling to keep up with the algae growth. I was shocking once a day or so, and the algae on the floors was pretty well cleared up, but I couldn't get it off the walls. Eventually I found this forum and learned a lot in a short period of time. It turns out that I may have been doing everything wrong over the past few years.

I've been using a few pucks per week of Tri-Chlor to keep a baseline chlorine level, and then shocking with Cal-Hypo once a week.

When I got my Taylor K-2006C, I ran a full set of tests

FC: 0
CC: 0
pH: 7.4
TA: 110
CYA: 160
CH: 1125

So my theory was that the pucks caused the CYA to climb over the past few years, which was rendering the chlorine ineffective, but not realizing that, I kept dumping Cal-Hypo in which increased the Calcium level to where it is.

This past week, I drained the pool to fix the CYA and CH levels with plans to re-fill and use liquid chlorine only once the CYA levels were where they should be. Now that the pool is drained, I'm a little worried about what I'm seeing. The surface is pebble, but it's like there's a coating of white dust caked onto everything that doesn't really come off. The pebble cement base used to be a bluish color, but now everything is a grayish-white. I've hit a section with a power washer for a little while, and there isn't a noticeable difference. It's on all of the walls, the floor, the light lens and bezel. I included a photo of the light bezel because it's most clear on that surface (I think). I'm not quite sure what to do next at this point and could use some advice. If it's calcium all over everything, should I have the surface cleaned before refilling? Should I refill and then do something? If so, what? I'd hate to re-fill, and then find that I have to drain it again to have the surface cleaned.

Thanks in advance for any advice and guidance.
 

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JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,281
Tucson, AZ
It’s calcium scale. If you scrape some of off the fixture and add it to a plastic cup with some vinegar it, it should fizz like soda for a bit and dissolve.

The only thing an outside company will do is say you need to acid wash your plaster but that is like trying to use a nuclear bomb to get rid of a mosquito. All acid washing will do is severely etch your plaster, restore some of the color, make it rough and shorten it’s lifespan.

You could refill the pool first, get the water balanced, SLAM the pool to destroy any algae (because draining and cleaning doesn’t necessarily kill all the algae) and then worry about the surface. A “no drain acid wash” (also known as a Zero-Alkalinity Treatment) could help to redissolve all that calcium scale. It will raise the CH of the new water a bit but not nearly as high as what you had and you could reduce the CH slowly over time by replacing water.
 
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Kconstan

Active member
Apr 25, 2020
33
Burbank, CA
Thanks guys-

Is there anything that needs to/should be done before starting to refill? I'd hate to miss an opportunity while its drained to take care of anything. I didn't bother power washing the whole thing because the spot I did didn't make an appreciable difference.

Assuming there's nothing else that needs to be done, the plan is:
Refill
Check the chemistry and report in
SLAM
Come back for a how-to on the "no drain acid wash"

I'm curious whether the calcium left behind on the surface will get re-disolved back into the water after refilling, or if it's on the surface until the no-drain acid wash, and then how much it ends up raising the CH.

Thanks again
 

Kconstan

Active member
Apr 25, 2020
33
Burbank, CA
Alright! The pool finished filling last night around 7pm. I started the filter up, and re-charged it with ~7lbs of DE.

Just ran a fresh set of tests:
FC: 0.4
CC: 1.6
pH: 8.0
Acid Demand: 3 drops
TA: 190
CH: 170
CYA: 0

Here's test results from the fill water for comparison:
ph: 8.0
TA: 160ppm
CH: 150ppm
CYA: 0

I'm guessing that the first steps are going to be to get TA and pH down, and CYA up. I was thinking about bringing the CYA up by adding some tri-chlor pucks (since I have a bunch left over from doing this all wrong all this time), but I'm not sure how many I should plan on putting in or how long it might take for it to get the level up given that they dissolve over the course of the week.

It seems like PoolMath is a good resource for getting TA an pH in line. I'll be adding 2 gallons + 2 cups of 14.5% muriatic acid to bring the pH down to 7.2, but I'll probably do it in 1/2 gallon increments over several hours into a return jet.

So my unknowns are, when to add chlorine, and if it's alright to bring CYA up by adding tri-chlor pucks. I don't have any other CYA on hand, so this would be the easiest method for me. Not sure how many to add though.

Thanks all!
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,024
Laughlin, NV
Add 30 ppm worth of CYA using the sock method. Keep the pucks for later when you are on vacation or just need a little CYA boost.

Add 3 ppm FC worth of liquid chlorine now. Test and follow the FC/CYA Chart for 30 ppm CYA.

Keep pH in the 7's. The TA will fall over time.

CH is kind of a decision. With evaporation, your CH will rise as you use your fill water. Do you cover your pool at night?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,024
Laughlin, NV
Until your CH rises, do not lower your pH below 7.6. And the high TA is helping right now, so do not rush to lower it.
 

Kconstan

Active member
Apr 25, 2020
33
Burbank, CA
Thanks for the quick replies Marty-

I'll try to get my hands on some CYA. Trying not to leave the house if we can help it.

I don't cover the pool at night. Are you saying it's a decision because the level is low at the moment, and likely to rise over time, so it's not clear whether to raise it right now? I also have some cal-hypo on hand that I could use to both bring the chlorine and calcium up if that's useful?

So I'll shoot for pH of 7.6 for the time being with muriatic acid.
 

Kconstan

Active member
Apr 25, 2020
33
Burbank, CA
Back with an update and I could use some help. I started my SLAM on May 14 (last thursday morning). I've been trying to keep the FC around 12, and I'm checking about 3 times a day (~8am, ~noon, ~6pm). Typically the FC has dropped down to 8-9, and I'll add more liquid chlorine according to pool math.

When I started the SLAM, the pool water was already clear because I had done a complete re-fill. The issue that has me concerned is that prior to the drain, I had a lot of yellow algae on the walls that I couldn't get rid of. When I did the drain, the algae seemed to go away (the walls were no longer yellow), with the exception of an area just below a built-in fill pipe. That fill-pipe seemed to have a leak and the wall never really dried out during the drain/fill. It remained wet, and yellow along with a ring around the bottom of the deep end that also never really dried out either. I figured, I'll just refill the pool and the SLAM will take care of it.

I've tried rubbing a tri-chlor puck on an area of the stain, but it seems like that just dissolves into the water and doesn't really stay on the stain. I've been brushing the stain 3-5 times a day with a 5" wire brush since Saturday. When the sun hits things, It looks like its fading, and then when its back in shadow or the sun has gone down, it doesn't look any different than it did at the beginning.

I'm looking for any advice on what to to do with this stain. It's the entire height of the wall (10') and on the floor of the deep-end, so if tri-chlor is the answer (I'm probably getting ahead of myself), how do I keep it applied to that area? It's frustrating to have a clear pool but not being able to use it because of this area.

I've attached a couple photo of the wall. There's a pumice stone on the coping to hopefully provide a reference point.

Thanks again so much for all of the help.
 

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Kconstan

Active member
Apr 25, 2020
33
Burbank, CA
Thanks! I filled with city water. The thing that makes me think algae is that it's the same color as the walls were prior to the drain/refill.

A few questions:

Is it sufficient just to get some tablets from CVS, or are there other better sources with fewer "other ingredients" in the tablets?
Let's say that Vit-C does lighten the stain, how do I get it applied to the area?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,024
Laughlin, NV
Regular cheap vitamin C will work.

You call that a fill line. Do you add water there? What is it tied into? Any galvanized steel lines? Or copper?
 

Kconstan

Active member
Apr 25, 2020
33
Burbank, CA
I don't fill from there. I filled using a hose (for the drain/refill and evaporation refills). I'm not sure if that line is galvanized or not as it runs underground from the front of the house. What I've called a "fill line" runs under the pool deck to the side of the house where there's an anti-siphon valve. At the house, it's copper piping, but I'm not sure what is run beneath the ground.

The only reason I know its leaking some amount of water is that during the drain, the wall remained wet in that area. It doesn't leak enough to offset evaporation.
 

Kconstan

Active member
Apr 25, 2020
33
Burbank, CA
I basically took the puck and scraped it against the pebble from the tile-line down to elbow-depth. I've done it probably 5 or so times over the past few days. I tried to do it elbow-deep so that there would be a line where I stopped. I haven't seen much of a change. What I don't know is if the tri-chlor just gets absorbed into the water and isn't really staying on the stain long enough to do anything, or if it isn't algae and I'm barking up the wrong tree.

Prior to the drain/refill when I had algae, I left a puck on the tile ledge of the skimmer and that left a nice circular clean area, but it took some time to do that (more than 10 minutes). I'm not sure how to do that same test on the wall so that the puck makes contact for an extended time.