8 year old pool starting to pit and yellow

[omagic12]

I live in west central Florida.Pool is screen enclosed and has a few plants (inside of screen) around the perimeter. Residential home with in-ground 12,000 gal. pool/spa combination. The pool/spa is 20 years old and originally marcite. I had it renovated 8 years ago with diamond-brite, new water-line and perimeter tile, 2.5 hp pump, pump chlorination and paper filter housing. I do not use solar panels and there isn't a heater for the spa. Chlorine/acid care (no salt).

I have done the maintenance since three months after renovation. I am not a fanatic when it comes to pool care, but I am not a total slacker either. I brush it and vacuum it roughly every two weeks and generally test the water once a month or more. Last year I was getting mustard stains more than I cared to and my father-in-law suggested I use 1 chlorine tablet for the pump's chlorine dispenser and 1 in a float dispenser. I have been doing that since the beginning of this year with very good results. Fewer mustard stains and less need for other chemicals (stabilizer, alkalinity increaser, sodium).

The pools been forming crystals for the past few years due to 1) our local water and 2) bad advice (water test) form a pool store to add 10 lbs. of sodium when none was needed. For the past few months there looks to be increased pitting and yellowing stains (not mustard) that doesn't brush off. The yellowing is on the side that gets the least amount of sunlight. I did some research on-line and seems this is somewhat common to diamond-brite as it nears the 10 year mark.

My questions are:

1) Is this common to diamond-brite or other surfaces

2) Anything I can do to slow the pitting, yellowing and crystals.

3) Can it and/or should it be acid washed

[mlparham]

I live in west central Florida.Pool is screen enclosed and has a few plants (inside of screen) around the perimeter. Residential home with in-ground 12,000 gal. pool/spa combination. The pool/spa is 20 years old and originally marcite. I had it renovated 8 years ago with diamond-brite, new water-line and perimeter tile, 2.5 hp pump, pump chlorination and paper filter housing. I do not use solar panels and there isn't a heater for the spa. Chlorine/acid care (no salt).

I have done the maintenance since three months after renovation. I am not a fanatic when it comes to pool care, but I am not a total slacker either. I brush it and vacuum it roughly every two weeks and generally test the water once a month or more. Last year I was getting mustard stains more than I cared to and my father-in-law suggested I use 1 chlorine tablet for the pump's chlorine dispenser and 1 in a float dispenser. I have been doing that since the beginning of this year with very good results. Fewer mustard stains and less need for other chemicals (stabilizer, alkalinity increaser, sodium).

The pools been forming crystals for the past few years due to 1) our local water and 2) bad advice (water test) form a pool store to add 10 lbs. of sodium when none was needed. For the past few months there looks to be increased pitting and yellowing stains (not mustard) that doesn't brush off. The yellowing is on the side that gets the least amount of sunlight. I did some research on-line and seems this is somewhat common to diamond-brite as it nears the 10 year mark.

My questions are:

1) Is this common to diamond-brite or other surfaces

2) Anything I can do to slow the pitting, yellowing and crystals.

3) Can it and/or should it be acid washed

Failure to maintain proper water chemistry on a more regular schedule than you have can result in the problems that you have encountered. At the bottom of this post is a link to a study conducted by the University of Florida's Department of Materials Engineering that addresses issues related to poor water chemistry in Marcite finished pools. I suspect that the same problems would occur in a "Dimand-Brite" finished pool.

http://www.floridabuilding.org/fbc/committees/education/educaton_tac/bldg_research_files/research_reports/swimming_pools/74.pdf