Need guidance on Water filtration systems

[jimjimmyjimjim]

I did a search for this information but gave up after a half hour, but if you know of any threads on point pls let me know.

I have brand new stainless water tanks and I'm trying to decide on a water filtration system. I have one head, a separate shower and the galley.

Should I go whole boat system or POU under sink system?

The advantages of a pou system are that I only filter a couple of gallons a day for drinking and cooking. But the disadvantages are the under-sink space, the waste water of around 2 gallons waste to 1 gallon clean, and I'd need a dedicated pump for the filters.

The advantage of a whole boat system is that I could fill the tanks and forget about it, and since I fill my tanks from a dock hose I don't need a separate pump and I can use shore power to power the system. The disadvantage is that systems that pump a reasonable gpd are very expensive. That extra money would be cleaning water that doesn't need to be clean.

So, what have you found works best? Do you have recommendations for a water system for either POU or whole boat?

Thanks, Jim

[Bowdrie]

You'd be amazed at the "stuff" that gets/grows in the tanks over time, my tanks have inspection ports and I'm a believer.
I too fill from the dock and use one of those "Culligan" filters on the hose before the water goes in the boat.
The boat uses the whole-boat filtration with another filter like the other and the water heater and sinks get clean water.
Water heaters last longer when fed clean water.
Not really a gripe but the filters, together with the space around them needed for changing elements sometimes requires "real estate" that you don't want to lose.
Like most devices and gizmos on a boat I guess it has something to do with how much pain and suffering you're willing to trade for accessibility.
Dockside filtration pays off.

[rslifkin]

The waste water is only a concern if you go for an RO system. If you stay with just a filtration system, there's no waste regardless of how big the filters are or where you put them.

I'm just wrapping up some upgrades to my water system. In the process, I added a whole boat filter system (plumbing-wise it's after the pressure/accumulator tank and just before the hot/cold split so everything gets filtered). I plumbed things to minimize distance from the filter output to the galley faucet, figuring that's where most drinking water comes from.

As far as the filters used, I went for 3 of the big 10x4.5 housings. Filters are as follows:

• Pentek DGD-2501 (1 micron sediment filter)
• Pentek DBC-10EX2 (granular carbon and KDF)
• Pentek Floplus-10BB (0.5 micron carbon block)

I figure that any semi-decent tap water that's biologically safe going into the tank should come out tasting fine and drinkable with that system (and my tank is fiberglass, so I can add a bit of bleach if needed). Water going into the tank will also get filtered with one of the large Camco RV hose filters (rated at 20 micron for sediment removal). The carbon, etc. in the Camco filter won't do much if filling full speed (might remove a tiny bit of chlorine), so it's mostly to keep sediment out of the tank (making it easier to keep the tank water clean and fresh).

[Shrew]

What is the GPM on the 'whole boat' system??

Many water purification systems I've looked at have a much lower GPM rating (e.g. .08 - 1 GPM) than the pressure pump (3-5 GPM)

[rslifkin]

Originally Posted by Shrew

What is the GPM on the 'whole boat' system??

Many water purification systems I've looked at have a much lower GPM rating (e.g. .08 - 1 GPM) than the pressure pump (3-5 GPM)

Flow rate is why I went for the bigger filters (and I've got enough vertical clearance to switch the sumps and filters out for 20x4.5 units if needed as the filter heads are the same for 10x4.5 and 20x4.5). Even with the pressure drop through the filters, my system will flow 3 - 4 gpm (which is all the pump can do anyway once the pressure tank bleeds down).

However, the carbon filters will remove less chlorine and other stuff at high flow rates. My system should maintain good chlorine removal up to somewhere in the 2 - 3 gpm range, but 1 - 2 gpm will be more optimal for any other potential smell, taste, etc. concerns in the water. Bigger filters (containing more carbon) will increase the usable service flow rate. In my case, the highest flowing faucet on the boat is only good for 1.5 gpm, so the only times we'd flow more than that are if someone washes their hands while one of us is taking a shower or something like that.

[GreenWave]

I use the Camco-like filters when filling my tanks. I use a Brita carafe filter for drinking water. You mostly want to control sediment going into the tanks. A little chlorine in them is good. ZERO chlorine might not be best unless you have quick turnover of what you put in.

[Captain Anthony]

following

[jimjimmyjimjim]

I'm concerned about bacteria, etc. in water at harbors outside the US. So, I'm going with RO and UV purification. That's why waste water is a concern as is gpm. With a whole boat system I'd be filling at a dock, so waste would just be a cost concern. A low gpm would just mean a longer fill time. However, if I use a pou system then waste water becomes a storage issue.

[rslifkin]

For bacteria, I'd plan to work on keeping it out of the tanks in the first place. So you'd want a good filtration and UV setup to use while filling the boat tanks. Filtering down to 0.5 micron and then running the water through a UV setup should get most water to be biologically safe. And then add some chlorine to the tanks (doesn't take a lot) to kill anything that makes it through and keep any bacteria, etc. from growing in the tank. Use onboard filters to strip excess chlorine out before drinking the water.

[Tellie]

I find a POU filter is best for any water consumed, I prefer SeaGull myself. But a simple 10" filter housing with a charcoal filter on the output side of your house pressure pump will give you a whole house filtration, enough for showers laundry etc.

[Madehn]

+1 on the seagull. I have two of them.