Water filter: carbon vs carbon and UV

[Letterkenny]

Pricing out the things I’ll need on my new boat coming in and this was at the top of the list. It’s a 34’ and I’d like to be able to drink the water out of the tanks. Mostly coastal cruising. I’m in Southern California. Water would come from the dock and I would do an initial pre-filter. I would like to add a secondary water tap that is filtered prior to output in the galley. Seems there are a couple options with two highly regarded ones being the Sea Gull IV and a H2O UV/sediment/carbon filter. The H2O is cheaper than Sea Gull at about $240 vs $660 but would like to avoid an extra battery drain if I could. Any other recommendations? Would a final 0.5 micron carbon block or sediment filter followed by 0.5 carbon block be just as good as either of these?

[Lepke]

The UV light needs to be on for a couple minutes before it's effective. And the light has an hourly limit after which it's no longer effective. I use a UV light after my watermaker only while making water. The bulb lasts about a year.
If you're on marina water, that probably means city water and that already has chlorine or similar in it. You don't need a UV light.
If you're on treated water, a sediment and GAC (to remove the chlorine taste) should be enough. Probably cheaper on ebay or Amazon.

[Letterkenny]

Originally Posted by Lepke

The UV light needs to be on for a couple minutes before it's effective. And the light has an hourly limit after which it's no longer effective. I use a UV light after my watermaker only while making water. The bulb lasts about a year.
If you're on marina water, that probably means city water and that already has chlorine or similar in it. You don't need a UV light.
If you're on treated water, a sediment and GAC (to remove the chlorine taste) should be enough. Probably cheaper on ebay or Amazon.

Thanks, was thinking something like that. The other concern though is that I’ll end up going to Ensenada at some point and may need to take on water there. What can cover us there? Afterwards, is it a full dump of the tank and then adding some cleaning additives?

[sv_pelagia]

Originally Posted by Letterkenny

Thanks, was thinking something like that. The other concern though is that I’ll end up going to Ensenada at some point and may need to take on water there. What can cover us there? Afterwards, is it a full dump of the tank and then adding some cleaning additives?

The problem with the water in Ensenada is its high salinity. Filters and UV will not deal with salt.

When we were there, one cruiser staying there a longtime bought an inexpensive reverse-osmosis system (from Home Depot, intended for a house) and successfully used it to remove salt from piped-in water. .

Like most, we had bottled water delivered to boat.

[purplesunrise]

If you want to eliminate hauling bottled drinking water and have water that tastes far better and is safer than bottled water (some vendors just run their source through a carbon filter), consider a standard under sink reverse osmosis system that has sediment, pre-carbon, post carbon and RO filter elements. They are less than $200 and make water that is delivered to a faucet at the sink. You will never have to worry about bacteria, viruses and most chemical contaminants. The only issue you have to consider is finding a way to route the RO's discarded water back to your fresh water tanks. If you dump that water overboard then the tank will empty very fast.

[purplesunrise]

Forgot to mention that salt cannot pass through the RO membrane which is why water makers work but require much higher pressure.

[sv_pelagia]

Originally Posted by purplesunrise

If you want to eliminate hauling bottled drinking water and have water that tastes far better and is safer than bottled water (some vendors just run their source through a carbon filter), consider a standard under sink reverse osmosis system that has sediment, pre-carbon, post carbon and RO filter elements. They are less than $200 and make water that is delivered to a faucet at the sink. You will never have to worry about bacteria, viruses and most chemical contaminants. The only issue you have to consider is finding a way to route the RO's discarded water back to your fresh water tanks. If you dump that water overboard then the tank will empty very fast.

I think I just said this re using inexpensive home/undersink RO system for questionable fresh water, such as Ensenada's salty fresh water.

If OP only visiting Ensenada (not rest of Mexico) and only for a short time (e.g., 1 week), then cheaper/easier to purchase bottled water. An undersink filter can further filter this if needed.

RO system for fresh ('ish) water not to be confused with RO system for salt water.


On a sidenote: We never "hauled" bottled drinking water. In the two places we purchased bottled water (Mazatlan and Ensenada), the price/bottle included delivery and putting the water into the tanks.

[canyonbat]

Originally Posted by sv_pelagia

The problem with the water in Ensenada is its high salinity. Filters and UV will not deal with salt.

When we were there, one cruiser staying there a longtime bought an inexpensive reverse-osmosis system (from Home Depot, intended for a house) and successfully used it to remove salt from piped-in water. .

Like most, we had bottled water delivered to boat.

The problem with a home RO system is it is very slow and uses 5 to 7 gallons of water to make a gallon of filtered water. The speed is why most have an accumulator tank to store the cleaned water.

[Letterkenny]

Yea I have a 4 stage RODI at my house for my fish tanks but didn’t know if they would be able to actually remove salt from the water. Any links to places or cheap water makers?

[Letterkenny]

Thoughts on the below for every day use (no Mexico)? Would the Seagull be better? Or would a cheaper alternative work? Plan to use a pre-filter whenever I add water.

[Tsuru]

I’ve used both a .5 micron carbon block and the Seagull IV. They both work well for removing chlorine and tank taste from potable water. I’m currently using the Seagull IV and feel it gives a little greater level of protection. That said you can replace a standard carbon block filter just about anywhere. Read up on both and make your own decision (both work well).
I don’t typically filter water going into the tanks. Municipal water has a small amount of chlorine that in my mind helps keep our already clean potable water system, clean.
Drinking water is filtered to remove chlorine or in our case plastic taste, among other things.

[Ivansgarage]

Originally Posted by Letterkenny

Yea I have a 4 stage RODI at my house for my fish tanks but didn’t know if they would be able to actually remove salt from the water. Any links to places or cheap water makers?

I don't know what you call cheap... but this guy has a lot of do it yourself water makers..

http://sunpurewatermakers.com

[s/v michaela]

We have lived in Ensenada at Marina Coral for 5 years. I use a sediment , carbon,and media filter for iron on the dock.. then all taps/ice machine etc,, are covered with seagull filters. Water tastes fine and tests fine as well... Not sure where the other boat was that posted was but they could have been down in the cheaper marinas in town. We have no issues with the water here.

[sv_pelagia]

Originally Posted by s/v michaela

We have lived in Ensenada at Marina Coral for 5 years. I use a sediment , carbon,and media filter for iron on the dock.. then all taps/ice machine etc,, are covered with seagull filters. Water tastes fine and tests fine as well... Not sure where the other boat was that posted was but they could have been down in the cheaper marinas in town. We have no issues with the water here.

"cheaper" marina was the excellent Cruiseport Marina, close to everything in town. (And that was 2013... water could be better now.)

Perhaps out-of-town Marina Coral has different water system. Good to know for those considering options.

Ensenada is a great place!

[thinwater]

Originally Posted by Letterkenny

Pricing out the things I’ll need on my new boat coming in and this was at the top of the list. It’s a 34’ and I’d like to be able to drink the water out of the tanks. Mostly coastal cruising. I’m in Southern California. Water would come from the dock and I would do an initial pre-filter. I would like to add a secondary water tap that is filtered prior to output in the galley. Seems there are a couple options with two highly regarded ones being the Sea Gull IV and a H2O UV/sediment/carbon filter. The H2O is cheaper than Sea Gull at about $240 vs $660 but would like to avoid an extra battery drain if I could. Any other recommendations? Would a final 0.5 micron carbon block or sediment filter followed by 0.5 carbon block be just as good as either of these?

You can do this for about $50 if you use industry standard stuff, and get parts anywhere. Get a standard 2x10 housing and use an NSF 53 rated carbon block filter. There is more to keeping a good system, so see the post below for details.



Sail Delmarva: Drinking Water Filtration--The Short Version


The Seagull is criminally overpriced for what it is, IMO. Just a good carbon block filter with a lot of hype.