Freshwater - Bad Odor

[Shrew]

I recently bought a new-to-me boat (circa 1999 model). When purchased the freshwater tanks were empty, though I had noticed a line of discoloration on the inside of the tanks. Since the tanks are poly and translucent, you can see what looks like a scum line.

Initially I thought there were holding tanks, however I was rightly corrected.

There is only a single deck fill which seems to fill both tanks. Each tank has a dedicated line to the pressure pump with its own shutoff just before the pump.
I still need to dig around to understand how the fill crosses over from one tank to the next.

I've started by pouring some bleach into the deck plate to treat the water in the tanks. Now the tank closest to the fill deck plate looks normal (no scum) however the tank further away still has a scum line and, of course, the water smells horrible.

I suspect that the bleach isn't properly migrating from one tank to the other. I'm contemplating a few options:

1) drain both tanks, pour bleach in first, then fill both tanks.

2) Pull the vent line on the tank which still has a scumline and pouring bleach directly into that second tank.

Lastly, (I'm not sure I want to label this as #3, I'm strongly considering a water filtration system for the entire boat. I'm considering placing the filter(s) either just before or just after the pressure pump.

Is this doable? Any thoughts on a 'whole boat' filtration system, including make, model or parts?

Any other thoughts or suggestions to attack this problem?

[a64pilot]

I do a whole boat filter, just go to a home improvement store and buy a whole house filter, the one with replaceable cartridges. I buy charcoal block filter cartridges for mine, they last for months. You want to clean your tanks of course, the filter is more of a precaution and catches fine sediments etc.

[Terra Nova]

Originally Posted by Shrew

...There is only a single deck fill which seems to fill both tanks...

Correct this first.

[MarkJ]

What brand of boat?

If its 1999 its pretty modern. Someone here will have one and will be able to advise.

[Shrew]

Originally Posted by MarkJ

What brand of boat?

If its 1999 its pretty modern. Someone here will have one and will be able to advise.

99 Mainship 350 Trawler. I posted on this site, despite being a MV because there is a lot more member participation here than on the sister site 'Trawler Forum'.

Technically, I don't think the freshwater system knows the make, model or type of vessels it's installed on. LOL!! I figured these systems are somewhat universal.

[ranger58sb]

Originally Posted by Shrew

There is only a single deck fill which seems to fill both tanks. Each tank has a dedicated line to the pressure pump with its own shutoff just before the pump.
I still need to dig around to understand how the fill crosses over from one tank to the next.

Originally Posted by Terra Nova

Correct this first.

Originally Posted by Shrew

99 Mainship 350 Trawler.

A common Luhrs Group installation -- when the boat is large enough to support two freshwater tanks -- uses one deck fill and a crossover hose from one tank to the other, so they're self-leveling. You might look for bilge pump-type hose, the clear wire-reinforced stuff. I'd guess from the opposite end of the tanks relative to where the feed to the pump lives. Might pass under raised floorboard in the bilge, if you have any of those...

(And once you find it, you might consider replacing that with decent sanitation hose rated for potable water... and insert a T fitting in the line so you can drain the whole system easily. Drain especially useful if you're in an area where you have to winterize.)

Many Luhrs installations only have a single feed to the freshwater pump, not dual feeds... but maybe that was a Mainship mod.

FWIW, our filtration system isn't built in. On purpose. We simply use two household sediment filter housings, with a dual-gradient filter element in the first (25 micron/1 micron) and a .5 micron carbon block element in the second.

-Chris

[Shrew]

Originally Posted by ranger42c

A common Luhrs Group installation -- when the boat is large enough to support two freshwater tanks -- uses one deck fill and a crossover hose from one tank to the other, so they're self-leveling. You might look for bilge pump-type hose, the clear wire-reinforced stuff. I'd guess from the opposite end of the tanks relative to where the feed to the pump lives. Might pass under raised floorboard in the bilge, if you have any of those...

I appreciate the feedback. You touch on a point that had me scratching my head. If there is a cross-over line between tanks for filling and 'self-leveling' purposes, then why have two shut-offs (one for each tank) at the pressure pump? since the pump will draw from whichever tank valve is open and the other tank will just backfeed into that tank anyway. If not for isolation purposes (which there doesn't appear to be) then why install shutoffs at all?

I tried to shut off what I thought was the dirty tank (port) , but (not surprisingly) it didn't help.

[ranger58sb]

Originally Posted by Shrew

If not for isolation purposes (which there doesn't appear to be) then why install shutoffs at all?

Don't know, unless there's a valve on the cross-over too. If so, perhaps they envisioned using those to balance the boat... or maybe to manage their water use, somehow.

??

There are several 350/390 owners on TF, I think. Certainly several active Mainship owners. Did you also ask on the yahoo group?

-Chris

[Tellie]

Originally Posted by Shrew

I appreciate the feedback. You touch on a point that had me scratching my head. If there is a cross-over line between tanks for filling and 'self-leveling' purposes, then why have two shut-offs (one for each tank) at the pressure pump? since the pump will draw from whichever tank valve is open and the other tank will just backfeed into that tank anyway. If not for isolation purposes (which there doesn't appear to be) then why install shutoffs at all?

I tried to shut off what I thought was the dirty tank (port) , but (not surprisingly) it didn't help.

Good question. But I'd bet once you find the cross over you'll find the shut offs for each tank as well.

[tml]

The valves for each tank are important. If one tank is empty the pump will be sucking air and won't work. On a sailboat; maybe not on a trawler the water if heeled can siphon from high to low leaving one tank empty and sucking air.
We filter thru household charcoal filter on the hose as the tank is filled. From experience you can easily have some strange and unexpected material riding along in shore side water. This way you stop it before it gets in the tanks.
Put a Seagull filter for drinking and cooking water in the galley. We have used one for 25 years, absolutely cleans the water up.
TML

[Deltasailor]

Originally Posted by Shrew

I appreciate the feedback. You touch on a point that had me scratching my head. If there is a cross-over line between tanks for filling and 'self-leveling' purposes, then why have two shut-offs (one for each tank) at the pressure pump? since the pump will draw from whichever tank valve is open and the other tank will just backfeed into that tank anyway. If not for isolation purposes (which there doesn't appear to be) then why install shutoffs at all?

I tried to shut off what I thought was the dirty tank (port) , but (not surprisingly) it didn't help.

Water left in tanks often (in hot weather) have a bad egg smell. Flush the tanks with clean water (not bleach) and add milton or other purification tablets. You will find the smell will clear after a few refills. A cut off valve stops the water running into the leward tank when healed. I never drink the tank water but use bottled.

[Dave22q]

Try running the tanks down to the crossover fill level. Then refill using lots of bleach. Add every few gallons not just at the start. After sitting a few hours drain again and see what you have. No matter how these tanks are cross connected this should get bleach into the bad tank. I would stay away from filters unless you plan to cruise where the marina water is frequently bad.

[Lepke]

Bacteria is airborne, too. Using water draws air into the tank to make up for the removed water. Eventually a colonizing bacteria starts growing in your tank. It's probably much worse for occasionally used boats. To stop growth permanently add a small amount of bleach when filling. Having a filter system after the tanks will remove any chlorine flavor. A pool test kit ($5 on Amazon) like I use is an easy way to control the amount of bleach. I add until it just registers on the bottom of the scale. At that level I can't taste the chlorine, but have filters anyway.

Most crossovers have a valve to stop cross over when necessary. And single fills often have valves to divert water into the intended tank. If all else fails, have the broker call the former owner.

[Pelagic]

What type of water heater do you have?
Small HW tanks often have the worst smell if left unused for a long tine

[Elie]

I had this problem with my water tanks. Bleach, and all other chemical solutions worked for a time, but did not solve the problem at its source. I removed each tank, cleaned it seriously, with a brush back to its original new state. And it never re occured again...