Abalone shells have, in the past, caused problems with plaster discoloration, specifically brown rings forming around the shell chips. The culprit seems to be non-pool grade shells being used that were not properly processed to remove all of the organics in them. These organics then slowly leach out into the plaster, react with chlorine in the pool water and form a brown ring. Nothing can remove the stain and the fix is often to simply chip-out and redo the plaster.
Discuss with the plaster applicator WHERE they are sourcing the abalone shells from. Abalone shells from a reputable plaster company and properly processed and rated for pool use should be able to be used. If the applicator can't GUARANTEE that the abalone is a pool grade material, then I would not use it.
While abalone can add a nice glittery appearance, I think the downside risks are not worth it.
Abalone, like all sea bivalves, creates it's hard shell from calcium carbonate and other minerals through biological processes. They are beautifully complex in that they use enzymes and proteins in the biological process to structure nano-scale (one-billionth of meter) material layers. Scientists and engineers would love to be able to recreate in the lab what nature has so beautifully constructed but, to date, the best humans can do is a very sad and simplistic process.
All that is to say that these creatures leave organic residues behind in their shells from the process of building them. It has be shown that abalone shells in white and light colored plasters can eventually cause brown staining (little brown halos) over time as the proteins and organics leach out into the surrounding plaster matrix. Chlorine and acid washing are not effective in fixing this.
Remember that abalone is a natural product that is derived from the shells of sea mollusks. They can and will contain organic compounds. If they are not processed and washed properly, problems can arise years later when you no longer have the PB on the hook with your money. These stains appear to be permanent and, in most cases, the plaster has had to be redone.
We have had members report brown stains in their pool from the organics in abalone decomposing. See...
I am first time user on TFP and joined up after seeing older post relating to the issues of Abalone Shell Chips causing brown staining in Diamond Brite Plaster. I am not referring to the shells losing their brilliance...this is an actual stain in the plaster around the shell Has anyone else...
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I have a pool plaster problem. There are greyish/brownish mottled areas--your posting that talked about "hydration" problems sound similar but I'm not sure . I've uploaded a picture and hope for some opinions on what my problem is. I have 20,000 gal chlorine pool with pebble tec that is 10...
www.troublefreepool.com