First I hope I am posting in the correct section... I saw a post regarding blistering in this section which made it seem correct but if not feel free to move it.

Basically I have a ..... spa We dont know what brand it is because the previous owners inherited it after they bought the house as did we.

It first had a few leaking issues which I repaired in hopes of using it.

Now I was looking at the shell today and it had a bubble... I pushed on it and it cracked and there was water underneath it.... now I have a 4" oval bubble thats cracked.. It is near the footwell edge where it starts to rise. I am assuming this is the acrylic backer that has lost its bond to the fiberglass.

Is this necesarily a bad thing? Can I just chips away until it is flat and have the fiberglass backing exposed? Since it is on the footwell it would never be seen.. or will this cause the entire sheel to slowly delaminate from this point...

Will water leak through the fiberglass..?? I highly doubt it... but will it... Should I fill it with some kind of glue/epoxy/something to seal it?

Any help is appreciated!

This is common with older tubs, and almost always start in the location yours did. There isn't much fix to the problem, aside from having the tub recoated. There are some acrylic repair kits out there, somewhere, where you just chip out the old and patch in with the new. The blisters are caused by moisture getting between the layers and that moisture is almost impossible to ever get rid of fully. You can leave the crack as is, epoxy the crack shut, or chip out the blister and put a resin coating over it so it isn't sharp. The last is what I've done in the past. It may spread, but more likely you will see other blisters start to develop around the footwell. Unless the fiberglass backing is cracked, you shouldn't see any leaks from this.

The fiberglass is definately not crakced... Ive looked all around for the leaks and got them all olved I believe... constant water level for 4 days is what lead me to that conclusion!

Uhmm am I ok with just some west systems epoxy over the are after I chip it out... Im not too woried because it is a fairly older tub.. I would guess about 10+ years old to be more exact....

So basically West Systems epoxy that dries clear over the are to stop chipping as well as keep it smooth....

Hopfully that brand won't darken. Most epoxys will darken with the heat and exposure to chemicals. It's all cosmetic so if you are ok with it, go for it.

Any specific one you recomend... and where I can get it?

I have no specific recommendations. Just keep an eye out for one that is suitable for being in water all the time, perhaps a marine grade?