removing orig water tank
The tank isnt the problem and is easily cleaned and restored to a sanitary condition. its the damn bio-porous water hose in a Pearson .... plus the ''usual'' contaminated "open to atmosphere" vent line. If you dont protect the vent line from aspirating spores, etc. you can expect contamination. Standard practice in pharm/bio/food industy is to protect EVERY water tank with a bacterial blocking vent filter.
The ''usual'' entry point of molds, mildews on EVERY boat''s tankage is the vent line. If you dont protect the tankage with a vent filter of some kind you can 100% expect contamination to follow. Many of these molds/mildews are very toxic; why let them into your tankage? Most vent lines are placed in hidden, out of the way, dark, damp undersurfaces ..... just where all that ''black ****'' lives on the walls of your boat! Do a websearch for aspergilis or Stochybotris autra.