How do I fix the Petri dish problem once I have it?

[Beartrack]

Ran some water through the freshwater tank this last week and found that the boat was stored with a full tank of water - you guessed it - out came green stuff in the water that looked a lot like moss strands! Any pointers from folks that have seen or ran into this level of biological stuff in their fresh water tanks on how I can clean it out and make it drinkable again? Thanks folks!

[rogerbum]

Fill it most of the way up with water and add some bleach 1/4cup per gallon. Leave it in the tank for a day or two. Rinse with 2-3 volumes of water. To get the water out more quickly/easily get a long piece of tygon tubing and attach it to the faucet. With the boat on the trailer, put the hose out the side window and use it to siphon out the tank. I couldn't find tygon tubing that was an exact fit so I built up the faucet diameter with a bit of electrical tape first.

[El and Bill]

Roger --
Spoken like a true biology labratory scientist -- nothing to add to your excellent solution, except, when you refill your tank after the cleansing, we add about a half bottle of cheap vodka. Kills the chlorox aftertaste, prevents return of the greenies, and makes a happy boat. That's the geologist addition to the biologist remedy.

[Pat Anderson]

A couple of comments - 1/4 of bleach per gallon of water is way overkill...a quarter cup per 5 gallons is actually effective with a couple of hours of contact time. The siphon hose does not have to be tygon - simple clear plastic tubing from the hardware store works fine, and one of the standard sizes just slips over the spigot on a CD22 perfectly (not all of us have the stuff in a DNA lab just lying around!) - a couple of foot pumps and off she goes. Finally, three water rinses should do it, but if there is any residual chlorine taste or odor, baking soda is the best way to neutralize it (not sure what vodka would do, but if it make Bill and the boat both happy, hey, why not!),

[MOOSE]

And another thing I recently did was to permanently remove the "sight-glass" tube, which was always so black and full of uncleanable gunk that I could never see what the water level was anyway. I took the tube fitting off the tank as well and replaced it with a similarly sized nylon plug from the hardware store. I always felt that tube was nothing more than a permanent breeding ground for the little off-tasting beasties.
Al

[Sea Wolf]

[BrentB]

How many use a point of use water filter?

[thataway]

A point of use water filter would be fine, but you still have to "kill" the problem. We use a Brita filter the kind you pour the water in a pitcher.
But we have a fine mesh screen in front of the water pump (my CD 25 does not have one, and I am going to put one in next week). Also remember that there are some micro-organisms which are not killed with Chlorox/bleach. (Cysts, such as Giardia and a fine filter is necessary for that)

I agree with Pat, that the 1/4 cup a gallon is pretty concentrated. But, some folks recommend a cup per 10 gallons. A cup is 8 oz, so 1/4 cup would be 2 oz. Generally "sanitizing" bleach is one tablespoon a gallon. A table spoon is 0.5 oz.. For just "purification" 8 to 16 drops a gallon is the recommended amount. One ounce equals 360 drops... Also check the concentration of Bleach, be sure it is pure bleach, and Bleach looses about 50% of its concentration in a year's storage.

Is an excess of chlorox going to damage anything in the system? Chlorox is hard on seals and rubber components--and it may be a little hard on the pump. I also usually go with a 2 to 8 hours of contact time--which is plenty. I would not go with over 24 hours. Be sure and get the concentrated bleach solution into the water heater for the "hot" water side, and all of the cold water tubing (including shower and deck fresh water wash down). Keep the water system pressurized while the bleach is sitting in the llines.

Another old RV trick is that is there are any tanks which you think might be clinging, put some ice cubes into the tank, and drive around until they melt (with the chlorox)--the ice cubes are mildly abrasive, will not harm the tank and help to clean the walls of the tanks.

I agree with the baking soda. Never tried the Vodka. (For killing bacteria in laboratory conditions, red wine ranked 3 to 4 times more effective than pure alcohol or tequila. The effective ingredient is believed to be phenol compounds enhanced from charred wood of the wine-aging casks.) It is difficult to get the chlorox taste out of the tanks. We would sanitize our water tanks every 6 months when full time cruising--I still do this every 6 months, even with leaving tanks "empty" during the winter and frequent usage the rest of the year.

Depending on where we pick up the water, we like to filter the water going into the tank, then add our own bleach solution. There are some pretty nasty smelling and tasting waters, plus some which have particles in the water, which we like to filter out--if you use a charcole filter, be sure and add the chlorox.

[BrentB]

yes treat and filter before filling the tank is highly recommended. POU filter is to trap live and dead bacteria and debris. However, bleach will not stop biofilms formation and will not kill not only Giardia cyst but also Cryptosporidium sp oocysts and many bacteria produce high amounts of slime that are resistant to high levels of free chlorine.

[rogerbum]

Bill - I like the vodka to help with the taste. I've used tequilla as a winter storage "anti-freeze". Add margarita mix and ice in spring and drive to the ramp. Drinks are ready at launch time! (Of course, don't operate the boat under the influence). An alternative solution to get rid of the after taste is to:
1) fill a glass with water from the tank
2) pour a shot of your favorite alcohol
3) dump out the glass and drink the shot!

[thataway]

Brent makes an excellent point--and unfortunately one of the cl resistant bacteria is cholera which is a pathogen. Incidently the Brita filter is not a steralizing filter, it is taste and odor filter. Filters like the Seagull IV and Nature Pure filters are specific for filtering out cysts, killing bacteria and viriuses. I tend to not trust these, because of potential filter "leakage" and depleation.

Some folks use filters which allow them to use "Lake water" for drinking--I would be afraid of overwhelming number of bacteria, if a boat was dumping raw sewage nearby.

[Beartrack]

LOL, ok, I'm a 15-year engineer and I still think I'm now on information overload a bit.

So I'm confused, short of straight Vodka , is there ANY way to use this tank safely again given all the potential contaminents, bacteria, slime, cysts, pathogens or who knows what else I've missed? I'm a software guy, not a biologist, but none of those things (especially having had giardia before) sound particularly appealing. Is there a sure fire way to kill all of this stuff or should I just be relying on bottled water now from here on out?

Thanks all!
Beartrack

[El and Bill]

Beartrack --
There are as many opinions as there are members -- but we'll share our experience. We simply drink the water. We verify that town water is the source of water at the marina, and town water is checked for contamination far more frequently than store-bought bottled water. Twice in our almost seven years of cruising, we have 'chloroxed" the tank, just as Roger described, because we noticed a few 'greenies.'

We have not had any illness related to water, and darn little illness from anything. (maybe because we are exposing ourselves and building resistance) -- who knows?

Now, backpacking for extended times, and being forced to drink spring water, we filter to avoid giardia -- on the boat, we drink town water from marinas that have a town water source -- no fuss, no muss, no diseases.

(Overseas, we only drink -- beer!) and never an intestinal problem.

[rogerbum]

Go with a dilute bleach solution. You can make it more dilute than I suggested and you'll almost certainly be fine. In general, as long as tap water from your local (already treated) source went in, the likelihood that the gunk growing in there is a human pathogen such as Giardia or Cryptosporidium is very slim. Giardia in water generally comes from human or animal waste in the water system and unless you've been misusing your fresh water tank, you probably don't have any in there. More likely, you have a green algae that looks ugly, tastes bad but won't kill you. The chlorine will get that.

As Bob said above, chlorine can do damage to rubber. The only rubber in the system on a 22 is the foot pump. If you don't pump the water all the way out prior to treating or immediately out after you add bleach to the tank, the diffusion rate through the long tube to the pump is so low, the chlorine won't be in contact with the pump during treatment. Then when you drain the tank, the rubber will only see chlorine for a few minutes. Once you run a few volumes of tap water through, you're also treating the tank to some extent as the local water supply is probably chlorinated (and fluorinated too!).

As for whether you use tygon or any other tubing - Pat's right - can be anything, Although the clear tubing you get at Home Depot or Lowes is often tygon (it's available to lawyers as well as scientists).

Most importantly, once you do get the tank clean, either empty it or change out to fresh water every week or two so you don't have to do this all over again.

[dogon dory]

Sorry, Folks - Post Deleted By Author