Confirm that I need an acid wash?

rodneyb

New member
Jul 26, 2010
4
Split off of this topic. JasonLion

I have a very similar situation. We bought a foreclosure and the pool looked similar to the pictures KenV originally posted. I have drained and pressure washed the pool, but I believe I have significant calcium scaling which requires a acid wash. I'd like to get the valuable opinion of others here to confirm that I need an acid wash.

Thanks,
Rodney
 

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PoolGuyNJ

TFP Expert
May 20, 2007
3,192
South Central NJ
I would try to knock it off with a set of flexible putty knives first. Use different widths, depending on the curves. Be careful so as not to gouge the plaster. The majority of the raised nodules, I will bet, will get knocked off fairly easily. Then you just sweep them up.

Try a two sq. ft. section to see if the results are satisfactory. The less scale on the walls, in any event, the less acid you will need. Acid baths tend to shorten plaster life because they can eat the plaster too, since it's high in calcium too.

Scott
 

rodneyb

New member
Jul 26, 2010
4
Now that I figured out how to share and link to photos, here are some more pics:

Picture of complete pool:


Spa:


Close up of light fixture:


Close up of tiles on step:


Black stain on step:


3 stains (slightly pitted) on pool floor:


Inside of spa:


And again, close of pool floor:
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,223
SWSuburban Chicago, IL
Wow. I've never seen anything that bad. Why is the bottom a different color?

Plaster pros...Is this something that if he filled it up above the tile line and had the PH very low for a few weeks, that some stiff brushes could help dissolve?
 

geekgranny

LifeTime Supporter
Aug 20, 2009
1,358
North Central Texas
frustratedpoolmom said:
Wow. I've never seen anything that bad. Why is the bottom a different color?

Plaster pros...Is this something that if he filled it up above the tile line and had the PH very low for a few weeks, that some stiff brushes could help dissolve?
It will probably take years and a great cost in pool products, and constant vigil of pH and all other water parameters to release all of that with any filled pool treatment and still be able to use the pool. Trust me I'm the QUEEN of calcium scale. I haven't seen the results of a filled pool major acid treatment (other than a two week AA treatment on my pool that only released a small amount of scale during the treatment) (you cannot use the pool during any of the filled pool acid treatments) nor if it will work on the pictured calcium scale all that well during a short but intense treatment.

What color is the plaster? If it is white then it won't be as noticeable doing a filled pool treatment that will last for several years. Calcium scale is the best magnet for organic stains and iron staining so micro-balancing and micro-managing is especially mandatory. How old is the plaster? Has it been acid washed in the past?

I would say that there are several things to consider, the most important one I can't answer. That is, is it better to do one major acid wash, or subject the pool to constant low pH while doing an extended filled pool milder treatment.

During this past winter, after a two week AA treatment in the fall, keeping the pH low and loads of sequestrants, with constant circulation, but only two big Slime bags, and many fine filter bag change outs on my Aquabot per day, for a couple of months while old filter was out of system, by March so much calcium had released that it took my new 80 sq ft DE filter, using cellulose media, several weeks to filter out the suspended calcium.

I would lean toward an acid wash as a cheaper alternative and to get it over and done with. ONLY if the plaster is in shape to take it. Sequestrants are expensive. I just ordered a case of Jack's Magenta and a $70 sequestrant test kit costing close to $340, no shipping or tax fees. I have been spending $60 to $100 a month for sequestrants, using HTH Metal Control, since last fall. I won't know how much the actual cost will be per month or if the JMagenta will work better (for the combo release calcium scale + keep iron staining at bay + slowly fade copper stain on plaster), until I use it for a couple of months. At least I won't be wasting money by using more than necessary by having the sequestrant test kit.

If acid wash is decided upon, work done by owner, please let the experienced people guide you. I learned a lot from making some minor, thank goodness, mistakes over the years.

gg=alice
 

geekgranny

LifeTime Supporter
Aug 20, 2009
1,358
North Central Texas
When I did the AA treatment I used about three to four times the amount of ascorbic acid called for in a "normal" AA treatment.

Oh yes, I forgot to add. Some may remember from my discussions of calcium scale, that when I and my tee-nitecy great friend did my last acid wash, I spent two hours with an angle grinder, using concrete discs, to get the scale off of one step. Also, and extremely important, it is really hard to control the acid etching on horizontal surfaces, even sloping (all of the pool bottom), especially if the scale is not uniformly thick. If the plaster is colored is is easier to detect when the plaster starts etching as the run off will be a very dark color of the plaster color. That's why I used the angle grinder on my one step. I didn't get to the other two because sustained an injury, during the acid wash; slipped on the slope because I didn't wash down the slope well enough, and tore a shoulder rotator tendon. The surface was damp but the released scale made the slope as slippery as ice. On flat or sloping surfaces the scale continues to release a bit even with good rinsing.

gg=alice
 

Melt In The Sun

TFP Expert
LifeTime Supporter
Oct 29, 2009
3,899
Tucson, AZ
Rodney, welcome to TFP!
Those pictures are impressive, but unfortunately not in a good way :( The picture of the light ring
I can't see any way to get rid of that much scale without an acid wash. Hopefully your plaster has enough life left in it! But hey, on the bright side, now that you're a member of the world's most awesome web forum, you can learn how to make sure it never happens again.

Where are you located, by the way? Summer heat really isn't good for exposed plaster, so hopefully you can get this figured out and the pool filled pretty soon.
 

rodneyb

New member
Jul 26, 2010
4
Thanks all for the replies. I don't think I'm ready to tackle doing the acid wash myself... I'm thinking it would be a lot of work and time and I don't want to mess it up. Also, I (actually more so the kids) want the pool up and running ASAP. This is the first pool for me and I unfortunately did not come across TFP until after I drained the pool which was right after we took possession at end of June. So it's been empty for 4 weeks now. At the end back yard, about 20 feet from the pool, the ground slopes down at least 50 feet, so I'm not concerned about the water table and the pool lifting. However, just in the last few days I've been coming across info about an empty pool being bad for the plaster. I haven't noticed any hairline cracks, so I'm hoping it'll be okay. Oh and I'll add we're in San Diego.

Can anyone tell me what I should expect the cost of an acid wash to be? The pool is 36x17. I have no info about how old the pool and plaster is.
 

geekgranny

LifeTime Supporter
Aug 20, 2009
1,358
North Central Texas
rodneyb said:
Thanks all for the replies. I don't think I'm ready to tackle doing the acid wash myself... I'm thinking it would be a lot of work and time and I don't want to mess it up. Also, I (actually more so the kids) want the pool up and running ASAP. This is the first pool for me and I unfortunately did not come across TFP until after I drained the pool which was right after we took possession at end of June. So it's been empty for 4 weeks now. At the end back yard, about 20 feet from the pool, the ground slopes down at least 50 feet, so I'm not concerned about the water table and the pool lifting. However, just in the last few days I've been coming across info about an empty pool being bad for the plaster. I haven't noticed any hairline cracks, so I'm hoping it'll be okay. Oh and I'll add we're in San Diego.

Can anyone tell me what I should expect the cost of an acid wash to be? The pool is 36x17. I have no info about how old the pool and plaster is.
Sorry I can't give you any info about cost as I've always done mine for 24 years (original plaster from 1981 to 1996, several for stains and calcium scale) and (1996 replaster to present for stains and calcium scale, 3 acid washes, last in 2008). But, on a brighter note, my pool sat half empty from late winter 2007 till early summer 2008, until the tadpoles matured, and then fully drained, for a month, mid summer 2008 until we did the acid wash. There didn't appear to be any damage from that exposure to Texas sun and heat, although it was an unusually "cool" and rainy summer. Also, the pool had more shade than it does now because of a tree that kept the sun off of about half of it part of the day and all of it from trees late afternoon on. I don't advise anyone doing this but just wanted to let you know that the damage doesn't always occur. My water table is very low. We have to drill several hundred feet to hit water. I was also, watering the "weeds" more, between rains, so the soil stayed pretty consistently moist.

gg=alice
 

geekgranny

LifeTime Supporter
Aug 20, 2009
1,358
North Central Texas
Sorry, I forgot. Welcome to TFP. :wave: What color is the plaster? Just curious. I would think that it will make the job easier if the plaster has color. Just my opinion. I've done both. My original plaster was white and current is medium blue.

gg=alice
 

rodneyb

New member
Jul 26, 2010
4
Thanks gg. I'm glad to hear that damage doesn't always occur to the plaster when the pool sits empty. As far as I can tell, the plaster doesn't have any color. It looks white or light grey, except as frustratedpoolmom noted, the sides have a bit of a light brown shade to them. I believe this is because there is more calcium scaling on the sides of the pool than the bottom.
 
G

Guest

Hi Rodney, and welcome to the 'page :party:

Do not acid wash your pool! You will destroy it at this point. I would also get some water in it in case we finally get some heat out here!

PM me if you want to talk. I'm in San Diego and am kind of familiar ( :roll: :lol: ) with pools; I might be able to help you get some answers.