Plymouth Marine Laboratories approached us for a food contact grade lining that could be applied in situ to their fibreglass mesocosm tank, which is used for the collection of deep-sea water samples. The problem they had was two-fold. One the tank was leaking and they were unable to locate where it was leaking; and the second was that the lining to be used had to be very pure and not contaminate the seawater sample.

We thought that the best solution was to completely reline the tank. We lightly abraded the internal surface by shot blasting, applied a new layer of fibreglass inside the tank bonded together with a food grade solvent free epoxy resin lining. During our work there we found that the floor of the tank was flexing due to a cavity under the tank where over the years the concrete had eroded creating movement of the floor as the tank was filled and emptied and fine cracks had formed at the base of the tank. We needed to fill the cavity but we could not move the tank and to inject the floor with a cement mixture would not have worked because of residual salt water under the tank. We therefore used an epoxy mix which filled the cavity and displaced the water and hardened very quickly thus solving the problem. The holes in the floor were sealed with epoxy resin plugs and then the whole floor was coated with the same system as was used on the walls and ceiling of the tank.