bubbles in water tank

[prescott56]

morning all,
just took the lid of an additiona water tank, it is a GRP jobby, looks good quality, nice and clean inside, except there are bubbles in the internal gelcoat. question is, can i just leave them or is it advisable to break them open and fill with epoxy, as per osmosis treatment ....sort of.
We don't generally drink the water, use only for washing, but do use for cooking, boiling spuds and such.
Any advise welcome.
Regards
Roy

 

[vyv_cox]

Almost certainly it is osmosis. I have such bubbles in my engine bilge and in the heads wash basin, where water can sit for extended periods. I also used to have the same, on a previous boat, in the inside surface of the hull where a flexible water tank sat.

Personally I would leave them in your circumstances. Have a look at them from time to time and take action if they deteriorate alarmingly.

 

[doug748]

I have had this for the best part of 15 years. I drain the tank over winter and give it a check, it has remained just about the same. Drinking water is not tainted esp as I use a filter as well.

 

[Pasarell]

It is osmosis but probably not worth doing anything about. Fresh water in contact with GRP is far more likely to cause osmosis than sea water.
The inside of my 20 year old tank is covered in blisters. None have burst and the water is not tainted although I generally don't use it for drinking. I empty the tank each winter and leave the inspection hatch off then clean the inside before relaunch.