[twilson0929]

I have 01 3800 Open I keep on the Chesapeake Bay. The boat has been at the current marina for 10 plus years. The water there is hard, I imagine straight from the marina swell. When I empty the tank to winterize (hasn’t been issue during summer because I keep at least 1/2 always) I am finding the freshwater screen filter full of what looks like a whiteish mineral deposit. They look like pebbles, hard but can be broken up, and they seem to somewhat stick to each other. Anyone experience same and find a good fix? I use a West Marine water treatment during the season. If I run the tank too low I will get this sentiment clogging the feed line. I have to use a compressor to blow the sentiment back into the holding tank. Any thoughts on dissolving or cleaning the tank without removing it is appreciated.

[ReelMagic]

On my 2003 38 Open I see similar white crystals as you described in the fresh water filter that is between the fresh water tank and the pressure pumps. The filter is located under the cabin floor where the fresh water pumps are...At the end of the season when I winterize the system I remove the screen and clean. I've done this for many years but the amount doesn't seem to affect preformance of the system when running on the pumps... Every once in a while I need to clean the filters at the faucet (galley and/or head).. Haven't seen any problem with shower...

[twilson0929]

This year seemed to be much worse than past. And yes the filter is prior to the pump so no issues seen at any faucet yet. In the spring I’m going to try some vinegar in the tank. Flush it well. Maybe that will help. Thx for commenting. Seems I’m not alone then.

[hiccup]

It's not from hard water. The dip tube in the tank is made from unprotected aluminum and slowly corrodes, creating those white pebble like pieces of the aluminum oxide in your pump filter.

It is common for the tube to develop holes over the years, preventing the ability to draw the complete contents of the tank out. Related question: are you able to completely empty your tank? Does your gauge read dead zero when the faucets start spitting air. I am going to guess no. Replacing the tube is fairly easy.

[twilson0929]

I have never let my water get that low to know if it runs dry at say 1/8 tank. My guage telling how full seems ok. Tell me more, I have no clue where that tube is located. Is the tank itself accessible and if so from where. I can get my manual off the boat and try to track. Guessing it’s below vacuum head under steps into engine compartment.

[ReelMagic]

On my 38 the tank is located under the stairs. There is an access plate that can be taken out. My guess it's 10x10 or so.. The top of the water tank can bee seen and the tank guage sensor is right there.. Can'r remember if the fill or supply hose are visable through that inspecgion port or not.......

[hiccup]

Perhaps you empty it when you winterize it?

The tank is under the cabin floor. Access to the dip tube is under the cabin stairs. The stairs have to be removed. It's not too bad, maybe 8 screws. Replacement tube is available online, McMaster Carr is a good resource. As a first step I'd empty the tank and see how low it gets before spitting air. An even more accurate way to measure usable capacity is to empty it and refill it with a meter attached to your hose that will tell you how many gallons it takes to fill. You can get one of those meters on amazon. I was losing out on about 30 gallons of usable volume due to the corroded dip tube.