Coating failure

[silas]

1 year ago we repainted a client pool. Grinding old paint off and degreasing surface. From memory the ratios of degreaser to water were mixed up and the brew was to strong. So we wash the shell very, very thoroughly. The chlorinated rubber paint over the next year bubbled badly. So we told the client not to worry we would sandblast and fully Plastering the pool for free, which we have just done. Washing the pool down and scrubing after sandblasting. Yeppee it happening again. It makes sense that its hydrostatic preasure on the walls but there was no indercation of this when pool was empty and dry. Any thoughts.
Cheers