125 Gallon with glass worn

[psi3000]

My neighbor just gave me a 125 gallon for a $170 paintball gun (unopened). When we got it over to my house and we noticed that there were two nipples of wear like maybe the previous owner had it filled with sand and the filter was sandblasting the bottom and gradually wore away part of the bottom surface. I am told this is a salt water tank so it is thicker than a freshwater. I am using it for freshwater. I have taken two pieces of Plexiglas and used Goop to adhere them around the two nipples that have the warn away part so any pressure gets spread around the worn nipples and not on them. I have two (three) questions: First: What the heck could have done this. Second: Do you think what I did would hold? And third : do you think I got a good deal (oh yeh it came with a stand).

 

[psi3000]

nothin? I am going to attempt to fill this today in about 12 to 18 hours. I would really love some input as to if anyone thinks I should just abort... OR any input at all. Even as to why there are two worn spots on the bottom of the tank.

 

[no.1chuy]

dont know what could have caused the wear spots but your guess sounds perty good. have you tryed asking your neighbor? well i've never seen this or have had to deal with something thing like that but is the goop water prof i know this sounds like a dumb question if it aint your really gonna apriciate me asking. what you did sounds good i think it'll hold