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Discussion Starter · #1 ·
The conventional wisdom is that leaving the chlorine in is positive, because it provides residual disinfection. However, for the typical user that adds water perhaps less than once per month, there isn't any residual after 2 days and the argument may be faulty if there is any dirt harboring growth that the chlorine did not reach. Additionally, the residual chlorine did nothing for the plumbing if the water was filled upon returning to the dock. Also, if the tanks was only topped-off 20-40%, the residual chlorine is almost certainly too little to provide consistent benefit.

At some marinas (mine) the water is from a well and is non-chlorinated. The residual factor is mute and I have always used a carbon/particle combination on the end of the hose (it is removed from the hose between uses). I rinse the boat a bit first to clear the hose.

Another point of view is that carbon will remove substantial TOC and other reducing agents that are required for bacterial growth. Yes, many bacteria can use CO2 as a source of carbon, but only if there is an alternate electron donor available, and carbon should remove many of these also. Given the water tank should be in complete darkness, we should be able to rule out algae.

Occasionally we hear of a tank gone sulfury; likely the bacteria are using sulfate along with organic material. Related to the question. That more tanks do not go sulfury (all water has sulfate) suggests

Any filter media can harbor growth, though KDF media is said to retard this.

A third option is to filter with carbon and then to add chlorine back. The carbon filtered water may have a lower chlorine demand. And extra step, of course.

And, of course, point of use filtration is a whole nuther' topic and I'm leaving it alone for now.

----

In the case of well water, more filtration is better, since the source is unsupervised. In the case of city water, I'm sure much depends on the municipality and even the infrastructure at the marina; is the hose reasonably clean?

Has anyone ever made a study of this? Too many variables, but I though I would ask.
 

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I know longer worry about the water on the boat. I keep my tanks clean but still worry about the water.
I installed a Nature Pure QC2 Purifier with Faucet for drinking water and for water for some cooking and coffee. One filter will do about 800 gals. As far as i'm concerned these guys are the best.

......and easy to winterize as well!!

This filter is fantastic!
Nature Pure QC2 Purifier with Faucet - Water Purifiers and Water Micro Filters - General Ecology
Marine / RV Water Purifiers and Micro Water Filters - General Ecology

Why Are We Different?

Legally- Purifiers must meet EPA Guide Standard Protocol for Microbiological Purifiers against bacteria, cysts, and viruses.

Most filters are intended to remove some taste and odors. Only a small selection of the very best water filters may remove specific protozo, and possibly certain aesthetic contaminants, providing a lesser standard of protection than that of General Ecology water purification systems. General Ecology purifiers remove viruses, bacteria and protozoa, PLUS many organic and inorganic chemcial and aesthetic contaminants at the highest "purification" micron level (0.4 microns absolute) to provide great-tasting water while protecting against water-related disease. (Please see published test results.)

Manufactured in the USA from the finest raw materials, our water purifiers are ecologically and environmentally compatible; they purify naturally without adding chlorine, iodine or other pesticides to the water you drink and use in your foods and beverages. General Ecology's "Structured MatrixTM" technology is independently certified to USEPA Purification Standards against all three classes of waterborne disease organisms - parasitic cysts, bacteria, and viruses - instantly, without pre/post treatment, without wasting water and without electricity. Outstandingly effective, they also remove chemical and aesthetic contaminants, providing superbly refreshing, spring-like water for a naturally healthy lifestyle.
 

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Discussion Starter · #4 · (Edited)
Legally, they need to be NSF certified to make those claims, and they are NOT NSF certified for bacteria and virus removal.

Check the NSF web site. EPA does not do the testing. I could be wrong--post what you find. NSF P231.
 

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NSF is only a 'recommendation' agency w/r to consumers, its up to the consumer/user to beware.

Most of the 'water purification gizmos' on the consumer marketplace are only 'LOG REDUCTION' devices ... maybe producing an effluent of 10E2 or 10E3/sq.cm 'reduction' of influent vs. effluent of the standard 'test organism' bacteria - brevundamonas (pseudomonas) diminuta ... - thats 100 or 1000 bacteria / sq. cm. on the 'upstream side' and one bacteria getting through the 'filter'. 'Sterility' occurs at a LOG reduction of >10E13 / sq. cm of filter surface area (1,000,000,000,000 on the upstream side and 'none' getting through) -- and youre definitely not going to find such on the 'consumer' market, not even with an RO machine.

Chlorine remains the choice 'retardant' for bacterial growth in USA water systems - the 'maintenance' dosage remains at 1 parts per million FREE chlorine - about 4oz. of 'clorox' per 100 gallons .... and yes it will only last a few days at that concentration level. Why keep the tank full when youre not using the boat ????????? Dont 'store' water in a boats tank; empty or draw down the tank when not using the boat for long periods .... no water = damn few bacteria, viruses, fungus, etc. etc. growing inside the tankage.
You dont keep water for long periods in your 'picnic jug', do you; so, dont do so with your boat's potable water storage.

Carbon (filters) ON a boat water system will quickly adsorb any free chlorine available, even if the water is non moving - chemical equilibrium is the driving force to remove the free chlorine onto the carbon. Bacteria 'thrive' on carbon in stagnant water system - they find it 'yummy'. Do your 'adsorption' and filtration before the water gets onto the boat.

I repeat prior my recommendation posted: do your filtering and 'carbon treatment' BEFORE the water gets into the tankage. Use at least a 1,2µM (absolute) filter that is certified/rated/validated for the 99.99% removal of oocysts on the end of your NSF rated for potable water dock hose. Put a carbon packed filter BEFORE the ≤1.2µM (the 2 filters in series at the end of the dockhose). Run the water 'as slow as possible' when filling your tank - it takes 'contact time' inside the carbon packed filter to affect good adsorption.
Add 4oz of 'clorox' per 100 gallons of delivered water .... then get your WIFE etc. to test for the
'barest possible' odor of free chlorine coming out of the spigot water.



You want to add a 'filter' to your boats water system .... put one on the VENT line to keep from aspirating 'micro-biologicals' into the tank when you 'draw' from the tank. A 0.5 sq. ft. surface area 0,2µM absolute rated hydrophobic media filter 'capsule' would do just fine.

;-)
 

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Discussion Starter · #6 ·
^^ All rational, except folks want to get to the boat and be ready to go, not wait more than an hour to fill tanks (as you pointed out, contact time matters--even large filters will be limited to 1 gpm or less). And it certainly won't happen a the fuel dock, with a line behind you.
 

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Rich_H,

Any links or sources to the filters you suggest? Are they commercially available or do they have to be custom made?

MedSailor
 

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The 1,2µM 'oocyst' 99.99% rated water filters are now found in most 'hardware' outlets. Just be sure to read the packaging carefully.
In the same place you will find carbon packed filters suited for potable water.

Several USA mfgrs of such consumer grade filters: Cuno, GE Water, Filterite, Osmonics
Be wary of 'asian' made and very low cost water filters.

To prevent getting expensively 'stuck' with proprietary shapes and sizes, the industrial 'standard' filter cartridge size is 2.5" diameter X 9-3/4" long or 2.75" diameter X 10" length.
 

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Helpful info- thanks all. Presently using a whole vehicle system with type B 3M filter ( carry two spares). Shock and flush system annually and add bleach at fill ups. We carry 200g and except when in my own slip pre-filtering is not logistically possible. Fresh water vents are above various sinks in boat and do not have in line filters. Have two water tanks. When in areas of high infectious diarrhea or other pathogens will use R.O. water from a tank dedicated to sinks and collect some in galleon jugs for chilled drinking water. Problem is the lines to showers, wash down etc. can also back feed sinks. This will force wasting water as will need to run water briefly before using it for drinking or brushing teeth etc. However, can't see a workable way around this.
The 3m filters are also used in RVs so commonly available at reasonable cost.
Straight diet of beer will make me fatter and dumber than I am already so this seems a reasonable compromise.
 

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A superior method for eliminating bacteria in water irradiates the water with ultraviolet light. Do a search on "ultraviolet water purification". This is the principal means the semiconductor industry uses to eliminate bacteria in incoming water supplies which would cause manufacturing defects when computer chips are fabricated. The process is scalable in the sense that higher incoming bacterial levels just require more/longer UV irradiation. A complete drinking water system combines UV light treatment followed by activated charcoal filtration to remove the dead bacteria which tend to get shredded in the process.

Chlorine is a common treatment enabling safe drinking water. However, chlorine is a very active chemical and can cause significant unintended system damage in a boat. A UV water purification system avoids this collateral damage.
 

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Helpful info- thanks all. Presently using a whole vehicle system with type B 3M filter ( carry two spares). Shock and flush system annually and add bleach at fill ups. We carry 200g and except when in my own slip pre-filtering is not logistically possible. Fresh water vents are above various sinks in boat and do not have in line filters. Have two water tanks. When in areas of high infectious diarrhea or other pathogens will use R.O. water from a tank dedicated to sinks and collect some in galleon jugs for chilled drinking water. Problem is the lines to showers, wash down etc. can also back feed sinks. This will force wasting water as will need to run water briefly before using it for drinking or brushing teeth etc. However, can't see a workable way around this.
The 3m filters are also used in RVs so commonly available at reasonable cost.
Straight diet of beer will make me fatter and dumber than I am already so this seems a reasonable compromise.
Suggest you check with your former place of employment as they are or should be soon in the process of adding 'end point filtration' to all spigots, showerheads, etc.

For a possible solution to water wastage from showers - thermally operated 12vdc solenoid valves to tank return, go to: Marine or RV water save.
 

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Carbon :) as rich said is good food

On are DI water units which produce 40 gallons per minute the carbon is step one and has to be backwashed two nights pre week to remain clean

1. 5 micron
2. carbon bed
3. 5 micron for carbon fines :)
4. anion and cation resin beds
5.5 micron for resin fines
6. UV CHAMBER
7 .02 micron microbial filter

Of this crazy list the coolest stuff you can by off the shelf NOW is low power requirement UV purification for backpacking
 

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Discussion Starter · #14 ·
Is the carbon "good food" or do the bacterium thrive on other compounds and materials absorbed to there surface? Given that fire char is quite durable in the environment and that granulated carbon is not very compostable, I assume it is the former. Most filter media are vulnerable this way, though the great depth and surface area of carbon make the problem more severe.

I've not been able to find much independent work on KDF (a copper/zinc alloy with some interesting behavior) media. Typically it is combined with carbon because there are some things it does better, and because it prevents infection of the carbon (a claim which EPA seems to accept). Unfortunately, like much of what goes on with carbon (combined adsorptive and catalytic processes), many of the mechanism are guessed at. You could say they are deduced from evidence and our understanding of chemistry, but seems to be a reach.

UV is interesting, but there are some challenges. I would like to hear the answers. I'm not sure how practical this is on a boat.
a. You could treat the tank, but that does nothing for the pipes.
b. You can treat the tap, but the lamps need a 20-30 second warm-up period. Most folks won't want to wait. Leaving it on is not practical because of the current draw.
c. UV is going to destroy plastic parts if the exposure is continuous. This is short wave UV, more damaging than sunlight. Just something to remember.
d. You're going to need some interlocks. Folks aren't going to clean the bulb sleeve unless they have to.

I don't think the "no filtration while loading" is the best approach. I fully understand the practicalities of time, but I've seen too much **** come from pipes; the more ****, the less chance I have of controlling growth in the tank. I started this thread in search of a middle ground with a rational behind it. In my mind the tank WILL become infected and the goal should be to minimize the amount of **** and biomass, so that down stream drinking water systems are not over loaded, and so that the water is still useable for bathing and such. Avoiding dead stink bugs, wasps, and **** from the inside of marina hoses and plumbing are the goal.
 

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PDQ has it right in my view. Issue is how far to take it. Very familiar with UV in medical setting but agree current systems not practical on a boat. Have thought about having just one on fresh water foot pump that's at the galley sink leaving the rest of the boat "whole boat filtered" but even this would be a chore. Rather for now just run the hose awhile fill a glass and look at it. The put it down and wait awhile. Look at it again. If not questionable to the look and smell test a sip and rinse. If still good fill her up. One of the issues not attended to often enough I think is stagnant tanks and plumbing. So the great thing about 200g is usually can bypass questionable water. The bad thing is you can have stagnant water if you don't flush your tanks whenever you get a chance and run water through all your plumbing.
Talking about flushes good to remember for those flushing their heads with fresh water is to avoid using heavily bleached water through your heads if you don't want to be replacing joker and duckbill valves all the time.
 

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Oh BTW when I was talking about water wasting I was referring the wasted water that occurs as you wait to flush the plumbing before use. Even got the bride to rinse-off- soap- rinse -off. a solenoid isn't a really that helpful.
 

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PDQ,

What are the goals of your filtration system? If I recall, you aren't cruising in third world areas, but you did mention that you're not on a municipal supply. Many systems, to my view, are built because people like the peace of mind that they get from having filtered water but usually, the water they're filtering is "clean enough" to begin with, at least from an infectious disease point of view.

Are you trying to decrease the chance of waterborne illness? Improve taste? Why not just get your well water tested and if it tests well, just let the low ph of your stomach do the sterilizing for you?

MedSailor
 

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A camelback all clear can do batch's in 60 something seconds and fit in your pack and make 80 cycles with its built in battery

How the hard part done how hard could it be to scale up a bit

Has the All Clear system been tested and validated by an independent laboratory? The All Clear unit has been thoroughly tested by a US EPA approved independent lab to ensure that it meets or exceeds the EPA standards for microbiological water purification devices. The results of the All Clear third party testing demonstrated that the unit reduced bacteria by 99.9999%, viruses by 99.99% and protozoan cysts by 99.9%. All Clear purifies water not only to stringent EPA standards, but to CamelBak’s uncompromising standards of safety and performance. - See more at: CamelBak | All Clear UV Purification FAQS
 

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Discussion Starter · #19 ·
PDQ,

What are the goals of your filtration system? If I recall, you aren't cruising in third world areas, but you did mention that you're not on a municipal supply. Many systems, to my view, are built because people like the peace of mind that they get from having filtered water but usually, the water they're filtering is "clean enough" to begin with, at least from an infectious disease point of view.

Are you trying to decrease the chance of waterborne illness? Improve taste? Why not just get your well water tested and if it tests well, just let the low ph of your stomach do the sterilizing for you?

MedSailor
You are on-target. Specifically, the Chesapeake area abounds with wells that are impacted by brackish water. Not so much that the salt is an issue, but enough that the sulfate can lead to sulfide if given the right circumstances. Keeping the tank clean is generally enough. I filter what I put in and I clean and dry the tank each fall; that has worked for me, but my wife would like better, and some of my dock-mates without these practices get some real stink going. I'm going to add a vent strainer (easy solution to a few bugs some years) and most likely some additional step, but I'm still weighing options. It will be something in a standard size--I hate proprietary fit stuff.

As an engineer I fully recognize that system design is based on needs--from a health perspective, mine are very small. But I also did not intend to discuss the whole system in the thread, just the question of weather using carbon is a plus or a minus when filling. The reason is that all of the hose-end filters are either carbon/particle or carbon/KDF/particle. They are handy for a small boat, though the contact time is so limited I'm sure function is too (I use a flow limiting orifice plate in mine).
 

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Discussion Starter · #20 ·
^^ The "All Clear" is a neat idea that is certainly functions for travelers. There is a pen using the same principle that has been well tested. Simple.

If I were traveling in really pestilential locations UV would be high on my list. All of the challenges are solvable. The problem I have with all of the systems I have seen is some impracticality of operation (they either stay on or they lack a warm-up interlock). But I'd need a health reason I do not have.
 
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