Possible Water tank Contamination - 2020

Our sight gauge is black. No telling how much fresh water we have with this! October 2020 - We are currently in Paradise Village Marina in Banderas Bay Mexico (by Puerto Vallarta)

 Debbie had noticed a sulfur smell in the head sink when water was coming out of the old faucet. She did some research on it and found out that the smell was caused by a harmless bacteria. We thought it was coming from the old faucet and since we wanted to replace it anyway, we did. Yet the smell continued. Since we live-aboard full time, we usually cycle through the water yet since we were in the boat yard for 17 days, we didn't use the water.

We found this out as Debbie lifted the floorboard to check the amount of water we had. Much to her disappointment, she noticed a blackness to the sight-gauge. So, we figured both 55-gallon tanks must be contaminated. Off to research the cure...

 Debbie went to her FB women's sailing group and found many posts about this subject. She decided to follow the bleach cleaning method since we have stainless steel tanks. The recommendation called for 1 teaspoon per gallon. Then Debbie found the conversion of teaspoon to cup - divide gallon by 48. For us this is 110 divided by 48 = 2.29 cups. We then decided to put bleach in each tank so that came out to be approximately 1.15 cups per tank. She also put a little into the sight-gauge to clean that.

 We'll let the bleach sit and run it through the waterlines, thus emptying the tanks. Then we'll refill them with fresh water and see what happens. Of course, we'll have to purchase bottled water for drinking, cooking, teeth brushing, etc.

Sight gauge clear again!  This treatment did the trick...no more foul odor!