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Discussion Starter · #1 ·
We know chlorine is a no-no, as the back flush will ruin watermaker membranes. Most water freshening additives are sodium hypochlorite, which is bleach. Are there any that are safe to use with a watermaker?

We have a carbon filter before the back flush water enters the watermaker, but that’s not reliable enough.
 

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Not really. If you need a tank sanitized, the best thing is to shock it, then empty and rinse a couple of times. Ongoing, most municipal supplies are OK because the chlorine dissipates after a couple of days of filling the tank, and your carbon filter can handle that amount. Another way is to treat the tank anyway you like, and flush the watermaker by filling a bucket with product water for flushing each time you run the watermaker - don't use tank water for flushing at all.

We have never had tank growth issues when regularly using a watermaker as sole water source.

Mark
 

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Discussion Starter · #3 ·
I assumed as much. Prior owner stuck in Europe during COVID. Boat sat. Tank fouled. Shocked twice now and still a slight musty odor returns. Need to return to potable. Drinking bottle for now, but would like to be able to drink from tankage.
 

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If the made water is for drinking... why not store it in a separate tank... or even small containers...limit the amount of product water and all the maintenance needed for the water maker.
 

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Watermaker is our only source of water and is used for showers, toilets, washing the boat, washing dishes, clothes - everything. Occasionally running a watermaker for short periods of time increases its maintenance compared to more frequent longer runs.

Mark
 

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Discussion Starter · #8 ·
One design flaw on our boat is it's single 260 gallon fresh water tank. I much prefer multiple tanks. At the least for redundancy in case of a leak, but also to fully dedicate at least one to the water maker and never ever contaminate it with shore water. Too late though.

I did install a carbon filter, but may have nuked it, during one of the shocks. The other possibility is contamination in the water lines themselves, which I know exists to some degree. When I cut the pex tubing to install the new household filter, I could see trace amounts of growth. Pex is not suppose to harbor much, but the chlorine might not have gotten past the filter much and at the same time nuked it's ability to filter for the remainder of the season. There was one aboard already, installed during the original shock, but it's element was only available in the UK and it had no bypass. The element was it's own canister.

I'm wondering if small sponges can be forced through the Pex, not unlike restaurants clean the lines on beer taps. Could be complicated to fit compressor fittings in the right places, but I think home brewers have a pump system for this too.
 

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One design flaw on our boat is it's single 260 gallon fresh water tank. I much prefer multiple tanks. At the least for redundancy in case of a leak, but also to fully dedicate at least one to the water maker and never ever contaminate it with shore water. Too late though.

I did install a carbon filter, but may have nuked it, during one of the shocks. The other possibility is contamination in the water lines themselves, which I know exists to some degree. When I cut the pex tubing to install the new household filter, I could see trace amounts of growth. Pex is not suppose to harbor much, but the chlorine might not have gotten past the filter much and at the same time nuked it's ability to filter for the remainder of the season. There was one aboard already, installed during the original shock, but it's element was only available in the UK and it had no bypass. The element was it's own canister.

I'm wondering if small sponges can be forced through the Pex, not unlike restaurants clean the lines on beer taps. Could be complicated to fit compressor fittings in the right places, but I think home brewers have a pump system for this too.
Have you confirmed growth in the fresh water system? Do you think it would be throughout or just inside the tank?
How bad is the contamination? Is it OK for cleaning purposes? If so, can you use some other storage for potable water?
My tanks are not large. I do not drink tank water. It's a minor inconvenience to bring bottled water. I also have one spout with a culligan filter I might use for boiling potatoes for example, I set up a convenient bottled water dispenser.

Brown Plumbing fixture Tap Blue Wood
 

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Discussion Starter · #10 ·
Yes, the tank had visible growth. I hand scrubbed as best I could but probably didn't get it all. I did get the slime off the bottom pretty well.

Our tank is a fiberglass built in, so the sides are a little rough and hard to scrub. I could get the raised part of the growth off, but it left a stain that would not scrub out.

While bottled water is working just fine for now, our long term plan is to head out for an undetermined amount of time. Till be want to come home. I bet it's at least two years, but who knows. Even then, we'd like to live aboard, without restrictions, for 6 months and home for 6 months. Not even sure where home will be at that point.

I have a few years to theoretically work this out, but I need to be able to drink the tank water at that point. I'd prefer to solve it now and take better care of it going forward.
 

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Discussion Starter · #11 ·
an inexpensive house carbon filter
I've just noted, while researching carbon filters, that ours has a max water flow of 2.5gpm. Our pumps should be doing far more, so it may also be our issue with onboard flow rates in showers and heads.

I installed a waterpur filter housing (mostly because it wasn't too tall like some others) and used these filters, which seemed to get good ratings. Of course, internet ratings are suspect.


Any suggestions for best filters and maybe better flow?
 

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Yes, the tank had visible growth. I hand scrubbed as best I could but probably didn't get it all. I did get the slime off the bottom pretty well.

Our tank is a fiberglass built in, so the sides are a little rough and hard to scrub. I could get the raised part of the growth off, but it left a stain that would not scrub out.

While bottled water is working just fine for now, our long term plan is to head out for an undetermined amount of time. Till be want to come home. I bet it's at least two years, but who knows. Even then, we'd like to live aboard, without restrictions, for 6 months and home for 6 months. Not even sure where home will be at that point.

I have a few years to theoretically work this out, but I need to be able to drink the tank water at that point. I'd prefer to solve it now and take better care of it going forward.
Minnie,
I don't know the architecture of your boat... but if it is possible... I would install new stainless steel or some material tanks you can properly clean. There are also bladders you could use too. Your OEM tank situation seem lousy!
 

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Those will restrict flow also. That's the problem with "good" carbon block filters - they are meant to operate at low velocity. Instead, use the cheap filters with the granular carbon like this: https://www.lowes.com/pd/Whirlpool-Carbon-Block-Whole-House-Replacement-Filter/50331855

The point here is that you will get your tank and lines clean, and the only purpose for the filter is to freshen taste. If you are running on RO water, there isn't any other chemical contaminants to worry about, and the 5uM filter will help with any algae or larger bugs.

I guess you could make the case that this filter won't do anything for those tiny harmful things everyone says will form in the water tank, but in 13yrs of full-time running we have never had these hypothetical things hurt us if they are forming.

To clean your lines, you need to shock them as well as the tank. Remove the filter, run the shocked water through all of the faucets until you smell bleach, then shut off and let sit overnight. Rinse well after.

I wouldn't try a sponge line through all of the systems, and think that would lead to grief. If it bothered me that much, I'd just replace all the pex. That stuff is silly cheap and easy to run and connect. I bet you could replumb your entire boat in a day.

Is your filter on the output or input side of the pump? If input, move it to output.

Mark
 

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Discussion Starter · #16 ·
Is your filter on the output or input side of the pump? If input, move it to output.
Funny, it’s a maze of pex tubing beneath the sole that transits between cabinetry. Hard to follow it all. However, the filter is proximally between where the tank is and the pumps. That‘s not to say it can’t be technically plumbed after.

Curious about why one matters over the other. I could pull the filter media and see about pressure impact.
 

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Discussion Starter · #17 ·
Your OEM tank situation seem lousy!
I’m sure the OEM would argue that the tank itself is nearly indestructible. I’ve had stainless and plastic tanks leak over the years. The metal tanks, probably due to chlorine corrosion. Plastic due to cracks.

Can’t defend the single tank. It’s huge and one would think it could have been bifurcated in the same spot. Just split into two tanks in the same space. But they didn’t.

They say the walls of the molded tank are treated with something other than standard gelcoat and fiberglass to keep the water potable. I’d hate to think I may need to re-coat them, but it’s not totally off my radar.
 

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Curious about why one matters over the other. I could pull the filter media and see about pressure impact.
Pumps can't lift a lot of head suction, but they can easily deliver pressure. You want minimal restriction on the suction side. Filters like you are using should be after the pump. If you want to keep material out of the pump that might damage it, then a screen filter on the suction side works fine.

Mark
 

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Discussion Starter · #19 ·
Filters like you are using should be after the pump. If you want to keep material out of the pump that might damage it, then a screen filter on the suction side works fine.
Found the fresh water system schematics. I have to give the OEM some credit here, they document absolutely everything. I have nearly 1 gig of files.

Indeed, the plumbing goes directly from the tank to the pumps, then back to the filter. I suppose it's a function of where they fit. I'm still not happy with the pressure. We have two fresh water pumps in parallel. 30psi and 3ish GPM each. I think that means 30psi and 6ish GPM results. I know we only get a couple of GPM at the tap, as I timed a bucket. I'm sure the plumbing run loses something, but it must be the filter backing things up.
 

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My understanding is that metabisulfite is recomended for periodic sanitizing. That is what I have used on some large industrial systems (oil field). Check with the maker.

This is NOT for water treatment, though it is commonly used for wine making equipment etc.
 
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