To keep them for 30 yrs is abit far-fetched. Even i, find it hard to believe fishes tat can live tat long. I have seen my uncle's tank the first time over at his new house when he did his housewarmin many yrs back (married and move out of my grandparent place). Hmm.....didn't really take note of the LS in there then. But couple of yrs backs due to this hobby have started takin note of the LS in his tank. Infact 2 eels he kept has been with him for yrs, very easily regonised due to some marking found on their body. To him is, anythin tat he added and survived the first 3 days will survive. Of coz he went thru the proper cycling tat was dn so many yrs ago...and whether he had any casualities durin the initial pharse> tat i dun knw but i believe his tank has oreadi matured until cannot mature. And tats may explain y he nvr use skimmer or is there a skimmer to start off with 15yrs back. Btw....durin his time dun think there is PS in the market yet. Seen him havin salt mix over at his place but how often he change water, i also dunno but i highly doubt he did it oftenly coz he still got his birds, planted tank, freshwater fishes and dogs to look after OR mayb its the maid tat do all these . Its a small little pet shop to me
Btw its not surprising tat ur uncle's fishes died due to the fact tat he juz mixed water and salt and tats it.
30yrs back and pple r keepin marine w/o all these hi-tech equipments and the LS last so we cannot commend tat a PS is a must. Juz like we can survive w/o Internet 30yrs back coz there isn't such a thing then doesn't mean we cannot survive w/o it now rite