Possible calcium scaling?

[lichen]

So, I've been sitting around pondering my pool, life, house maintenance, etc. In the process I have been wanting to be as proactive as possible about addressing any issues with my pool.

Recently, I ran the full gamut of tests on my IG plaster pool:
FC: 11
CC: 0
TA: 120
CH: 230
pH: 8
CYA: 100

My pH always ran a little high, and I figured that was just a side effect of maintaining high FC levels due to my high CYA. However, I got to thinking that I should work on verifying whether or not that is the case, which lead me into wondering if the splotches on the bottom of my pool is actually calcium scaling.

Ignoring the tree reflection, please regard the splotches:

After messing around with the pool calculator it looks like my CSI is around 0.46, which is getting close to the danger zone it seems like. In short, I think I may be realizing that I simply haven't been adding enough muriatic acid regularly enough. My plan currently, since I live in Texas and don't close my pool (it's just too Dang cold to get in it), is to use the calculator's suggested amount of MA to drop my pH down to about 7.2, and let my waterfall aerate it, and once it climbs back up, then do it again. I'm hoping come summertime I may see a marked improvement on the calcium scaling?

Does this seem like a reasonable plan? I believe all my other numbers seem reasonable (except for maybe CYA, I may consider doing a water replacement come summertime as well). Does anyone have any thoughts or input on this course of action?

 

[jblizzle]

Looks like calcium scaling to me.

I would suggest replacing some water to get your CYA to a manageable level (is it really 100? If the test read over 100, it could be much high). Then you can maintain lower FC levels which then allow you to actually test the pH correctly {the pH test will read artificially high if FC > 10ppm}

Once you can accurately test and maintain the pH, you would then want to just maintain the pH lower and at a negative CSI to slowly reduce the scaling (with a lot of brushing). The aerating to raise the pH and then adding more acid will not speed the removal of the scaling, but it will work to lower the TA which will eventually help to maintain a lower pH with less upward drift.

 

[Richard320]

Hey! When did you sneak in and take pictures of my pool?

Looks like scale to me, too. You might want to look through this thread of mine: progress-on-scale-t38568.html

 

[lichen]

Hey Richard! I actually just finished reading your thread and got some useful information from that as well.

So, it seems that if I'm understanding this right, if I want to improve the scaling situation I basically need to maintain a negative CSI (around -0.3?) and diligently brush and be patient?

I will work to lower to the CYA, but I'm not entirely thrilled about needing to replace about 9000 gallons (nor do I feel very environmentally conscious about doing it here in Texas where we have had bad drought levels for the past couple of years), but perhaps I can do it over the course of a few months. However, if I were to let my FC drop to around 8ppm and take my pH readings at that point, it seems like that should give me a decent idea of the true pH?

Edit: Not 100% on the exact CYA level. It's definitely reading close to 100 if not higher. I fear it could be much higher than I realize, but based on how FC levels behave, it seems to be at least in the neighborhood of that number. There is some sort of dilution test I could use to get a more accurate reading for higher levels, right?

 

[Richard320]

Hey Richard! I actually just finished reading your thread and got some useful information from that as well.

So, it seems that if I'm understanding this right, if I want to improve the scaling situation I basically need to maintain a negative CSI (around -0.3?) and diligently brush and be patient?

Yes.

I will work to lower to the CYA, but I'm not entirely thrilled about needing to replace about 9000 gallons (nor do I feel very environmentally conscious about doing it here in Texas where we have had bad drought levels for the past couple of years), but perhaps I can do it over the course of a few months. However, if I were to let my FC drop to around 8ppm and take my pH readings at that point, it seems like that should give me a decent idea of the true pH?

Yes, again. FC below 10 is good enough.

Edit: Not 100% on the exact CYA level. It's definitely reading close to 100 if not higher. I fear it could be much higher than I realize, but based on how FC levels behave, it seems to be at least in the neighborhood of that number. There is some sort of dilution test I could use to get a more accurate reading for higher levels, right?

Yes, again. Mix pool water and tap water 50/50. Then use that as the sample source that you mix with R-0012. Whatever reading you get, double it, and you'll be close. Try taking the reading several times - by pouring the mix back into the mixing bottle and then into the view tube.

 

[onBalance]

Yes, it looks like calcium scaling, but is hard to tell from the picture. If it is calcium scaling, then the plaster surface would be rough. Which areas are rough or crusty, and may feel like sandpaper? The lighter or whiter areas, or the darker and slightly gray areas? Or is the entire surface uniformly rough to the touch, or is it smooth everywhere? How old is the plaster surface, and how long did it take for the discoloration to show up? Calcium scale is white at first, then turns darker or gray over time as it attacks dirt and/or metals.

If it is a scaling problem on the plaster surface, then lowering the CSI (slightly aggressive water) and brushing as suggested by others above, is a good program to follow and to remedy. However, if it is not a scaling problem, it would not be appropriate to make the water aggressive.

 

[diasurfer]

This looks very similar to the pictures I posted here:

newbie-about-to-start-t54771-40.html

The feedback I got here leaned toward calcium scaling, but there is absolutely no difference in texture between stain and non-stain in my case. (In my pics I point out one or two little spots that are raised that I think are something else - patched holes from when the pool was drained and replastered). 99.99% of the stains are smooth.

I showed the pics to a pool store guy and told him the stains are smooth and won't rub off. He told me iron and copper generally are not an issue in the water here and his idea was that it could be due to high CYA levels. Indeed, my CYA was 135. I haven't read anything here about high CYA causing staining. Thoughts?

 

[RobbieH]

I wouldn't worry about replacing 9000 gallons if you are in Texas. Our water is cheap. 9000 gallons is nowhere near how much I use in a month. I can't tell where you are exactly, but we are about to get a whole lot of rain here in the Dallas area. If you are here, you could feasibly drain now and let the rain assist you in bringing your level back up. I'm seeing predictions of over an inch in my area and up to 3" to the south of us.

 

[CarrolltonTXPool]

Do use the full on wire brush or the part nylon, part wire?


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[duraleigh]

I haven't read anything here about high CYA causing staining.

It doesn't.

 

[chem geek]

If there's a high CYA level and a high copper level then one can get purple staining from copper cyanurate, but that's pretty rare.

 

[HouTex]

Yes, it looks like calcium scaling, but is hard to tell from the picture. If it is calcium scaling, then the plaster surface would be rough. Which areas are rough or crusty, and may feel like sandpaper? The lighter or whiter areas, or the darker and slightly gray areas? Or is the entire surface uniformly rough to the touch, or is it smooth everywhere? How old is the plaster surface, and how long did it take for the discoloration to show up? Calcium scale is white at first, then turns darker or gray over time as it attacks dirt and/or metals.

If it is a scaling problem on the plaster surface, then lowering the CSI (slightly aggressive water) and brushing as suggested by others above, is a good program to follow and to remedy. However, if it is not a scaling problem, it would not be appropriate to make the water aggressive.

+1

I can't really tell from the picture, but my pool seems to look like yours and I don't have calcium scaling. My surface is not rough and I've always maintained a negative CSI. I believe I have the etching phenomenon that onBalance has previously described on this forum.

 

[Rock Painter]

closed subject

 

[mhoy]

Curious about your diy water softener. Details please!!!

 

[Rock Painter]

closed subject

 

[duraleigh]

Rock Painter,

Tell us more. Remember this forum is looking at answers for the average pool owner....not someone who can use your device over and over as you would in your profession.

What would you estimate the cost to be for a pool owner to build his own?

 

[Rock Painter]

closed subject

 

[duraleigh]

Rock,

Thanks for the very nice words about the site. It's not me at all but the folks who contribute knowledge and help 365 days a year that make the sight great.

The moderators, in addition to being great contributors, are heavily involved in eliminating spam, flame wars, know-it-alls, etc. that are so common on other forums.

Once folks know the rules and realize they are enforced, the forum is a very congenial place to visit. I really do think we have the very finest pool forum on the net......but it's the members and the moderators that make it so.....not me.

Your DIY softener is very intriguing. Do you test CH before you start? What time would you guesstimate to get a 20k pool from somewhere around 600ppm down to 200ppm? Impossible to sbe very accurate, I know, but would you hazard a guess?

 

[Rock Painter]

closed subject

 

[HouTex]

Would the homemade softener work with a salt pool?