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
The picture of the light ring 
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.
:lol: ) with pools; I might be able to help you get some answers.