Shocking water tanks after emptying for winter?

[rslifkin]

Originally Posted by CarlF

I've never understood the need for a so much bleach for tanks that were clean before storage. After winterizing I do two or three 1/8th tank fills and empty to flush out the antifreeze taste from the piping. Then I fill and add bleach to about 5ppm on a test strip (pools are 3ppm). This takes less than a tablespoon of bleach for 100 gallons. I run this into all the pipes. After three hours I empty and then refill and test the chlorine level again - I'll add a bit of bleach if necessary to reach 1ppm which is municipal water level. If it is 2ppm or higher I'll empty and fill again.

Perhaps this is dangerous but I've been doing it for over a decade and to my knowledge no one has gotten sick. I don't allow bottled water on my boat because the tank water is so good.

If you're testing the chlorine level during the flush to ensure that the chlorine residual in all of the lines and the tank wasn't depleted, you're fine. More bleach is the safe option if you're not doing that testing, however. And less bleach also means the required contact time for disinfection is longer (3 hours may not be enough).

[sv_pelagia]

OP, we're lucky here in BC, unlike out on the east coast (or Great Lakes).

the "warmth" (it's all relative) of the sea water in the winter here in Southern BC will protect your water tanks from freezing for at least several days should there be a protracted power outage (unlikely where you are). This assumes your tanks are below the waterline. Hopefully, also for water lines.

Nevertheless, we do have an electric heater set to turn on at about 10°C.

Cold today, eh!


We keep our tanks full all year, but we do empty (and refill) them at least once per year (of course, we also empty/refill them through regular use many times May-Sept). We just drain them into the bilge (good for cleaning/exercising bilge pumps) rather than using the water pump. We don't "shock" them (not great anyways for our aluminum tanks).

[NYSail]

Many people do not use the tanks often and the water stagnates…… it seems I hear more people complaining about smelly water than people (like me) that drink the tank water. When water is available I use it to the extreme so the water is fresh and thus my tanks and lines stay clean.
When I bought my last boat, the water tank was literally black with chunks……. I did the major bleach clean as per “the head mistress” and scrub and after that all was squeaky good…..
I too do not have bottled water aboard as the plastic is toxic and adds too much garbage.
I do have a water filter (pitcher style) that we use for drinking, but for everything else (brushing teeth, cooking etc) it’s straight from the tap!

Greg

[NorthCoastJoe]

Peggy, what is your ratio for bleach in aluminum tanks? Or is hydrogen peroxide better?

[peghall]

Ratio is the same regardless of tank material. It's cumulative exposure to bleach that does the damage, which is what makes adding a little bleach to each fill a bad idea. The solution is in the tank for such a short time, and then THOROUGHLY flushed out, that it doesn't have time to do any harm to metal water tanks.



When I recommissioned mine, made it very easy job. I put the bleach solution in the tank last thing before turning in for the night. I'd brought bottled water to make my morning coffee, which I did while I drained the solution. I refilled with clean water while I made and ate breakfast. Tasted the tank water...if I didn't taste chlorine, I called the job done. Drained and refilled w with vinegar solution if I did. Stuck with bottle water for a couple of days before draining that.


--Peggie

[Mike OReilly]

I shock our tank every spring with re-launch. I do use antifreeze, so flushing the tank with bleach water, and then more water, is important.

I tend to follow Peggy's recommendation, although I don't fill our 200 gallon tank to the top, and I use a concentration that is somewhat less. In truth, I'm just not that fastidious about the exact amount.

Normal process is to fill maybe 1/2 the tank in the evening with the mix, and let it sit overnight. I run all the lines and facets, so the mix is sitting in the entire system. Then I pump it out in the morning, again running through all lines and facets. I then fill and pump water through the tank and system a few more times to get rid of any residual odours.

To avoid added wear&tear on my pressure pump I rig an external pump that takes the water from the tank and dumps it directly into the bilge. The bilge pump then finishes the job. This has the added bonus of cleaning the bilge out.

[CarlF]

Perhaps one reason I've never had a problem using less bleach after storage is that I keep the tank very clean. There's a sediment filter on the fill hose and I don't use the marina hose. I run the tanks dry every three weeks and fill fresh with municipal water that has some chlorine. If I'm making water, I'll treat the tank with bleach to 1ppm every three weeks too.

During winter storage the tank is empty except for a few gallons of antifreeze which doesn't support organic growth anyways.

I've done this since the boat was new so the tanks have never grown anything. The first time with a boat with unknown tanks - I do the full Peggy bleach concentration.

[desodave]

Originally Posted by sv_pelagia

OP, we're lucky here in BC, unlike out on the east coast (or Great Lakes).

the "warmth" (it's all relative) of the sea water in the winter here in Southern BC will protect your water tanks from freezing for at least several days should there be a protracted power outage (unlikely where you are). This assumes your tanks are below the waterline. Hopefully, also for water lines.

Nevertheless, we do have an electric heater set to turn on at about 10°C.

Cold today, eh!


We keep our tanks full all year, but we do empty (and refill) them at least once per year (of course, we also empty/refill them through regular use many times May-Sept). We just drain them into the bilge (good for cleaning/exercising bilge pumps) rather than using the water pump. We don't "shock" them (not great anyways for our aluminum tanks).

On the boat today dealing with the water and a couple of other things, getting it ready for the snow tomorrow. Cold was terrible !! Especially in the sunshine.

Both tanks are at least partially above the waterline ... it's more the lines that concern me. Boat has a liner with compartments so can't really drain them into the bilge.

We had a 12+ hr BCH outage last winter and the marina electrical system is very old as well ... probably trying to wear suspenders and a belt at the same time ! You're right ... we have an effective heat sink under us as well.
Just a spectacular view of the Coast mountains on the drive up from Courtenay today ... almost made me want to untie the boat and head for Desolation

[bgallinger]

Originally Posted by Jammer

That's a lot. Usually I would use like a 1/4 cup for an hour for that.



The right way to do it is to get free chlorine test strips (cheap at amazon etc) and use enough bleach to get a high enough concentration (ppm) for a long enough time to meet FDA/USDA guidelines. Water chemistry varies as does the nitrogen load in your tanks and lines so it is impossible to get the chlorine dosage right without testing. That is what I will be doing this coming spring.

Peggy, can you please confirm the amount of bleach to use is: 1 quart in 50 Gallons?

[peghall]

1 qt household bleach per 50 gal tank capacity is the ratio needed:



"The following recommendations conform to section 10.8 in the A-1 192 code covering electrical, plumbing, and heating of recreational vehicles (which includes boats). The solution is approved and recommended by competent health officials. It may be used in a new system a used one that has not been used for a period of time, or one that may have been contaminated.


--Peggie

[malbert73]

I have aluminum tanks so am not thrilled to use bleach. I imagine a 1 time use isn’t harmful?
I’ve never actually shocked my tanks or lines. I have a seagull filter and separate tap for drinking water. I use Aqua Mega tabs for my water tanks after running municipal water through an RV hose filter to remove chlorine. Water coming from taps for washing doesn’t ever smell. What am I missing?

[desodave]

Originally Posted by malbert73

I have aluminum tanks so am not thrilled to use bleach. I imagine a 1 time use isn’t harmful?
I’ve never actually shocked my tanks or lines. I have a seagull filter and separate tap for drinking water. I use Aqua Mega tabs for my water tanks after running municipal water through an RV hose filter to remove chlorine. Water coming from taps for washing doesn’t ever smell. What am I missing?

Have you ever emptied your tanks and left them for a period of time? That's what we're doing and why we're shocking them ... to make sure anything that grows in a damp environment is killed and the subsequent water in them is safe. I've never seen anything that suggests a need to do it on tanks left filled, but I'll leave the answer to that question to someone more knowledgeable.

[malbert73]

Originally Posted by desodave

Have you ever emptied your tanks and left them for a period of time? That's what we're doing and why we're shocking them ... to make sure anything that grows in a damp environment is killed and the subsequent water in them is safe. I've never seen anything that suggests a need to do it on tanks left filled, but I'll leave the answer to that question to someone more knowledgeable.

Yes, every single winter I empty them [emoji3]
Of course, I recently installed deck plates in an inspection port on each tank and shop Vac’d out all of the water so they are dry and will air out. But prior I didn’t do that.

I mean, the logic makes a lot of sense to do it. And I am fastidious about boat maintenance in my 15+ years of ownership. So I’m asking the question of does everyone do this and I missed it somehow

[Sailor Sailor]

Originally Posted by malbert73

Yes, every single winter I empty them [emoji3]
Of course, I recently installed deck plates in an inspection port on each tank and shop Vac’d out all of the water so they are dry and will air out. But prior I didn’t do that.

I mean, the logic makes a lot of sense to do it. And I am fastidious about boat maintenance in my 15+ years of ownership. So I’m asking the question of does everyone do this and I missed it somehow

Yep, I do what you do. Empty the tanks, pump out the hoses, clean the filter, vacuum out all the water, and leave the inspection ports open to air dry. I look inside the tank with a flashlight to ensure it is dry and clean. Seems to work well.

In the Spring, fill water with bleach mixture - 1/2 cup for 44 gal., run through the entire system, allow it to sit for a short period of time, then drain and fill with small amount of bleach to stand for a week or two.

[Sam Woodbridge]

Did you guys know Peggie Halls book on boat odors is on Amazon? It also on a digital format which I didn’t know until a few days ago!

And that prompted me to buy her book!


Sam