Full or empty water tank in tropical temperatures

[Oceansailor]

Originally Posted by sailorboy1

You don’t feel you have been answered? Because I feel you have.

No problem. I understand you have a bad day.

[sailorboy1]

Originally Posted by Oceansailor

No problem. I understand you have a bad day.

What?????

Did you not even read the answers I and others posted.

[DMCantor]

We have for many years emptied the water tanks when hauling out, and have always had good tasting water when we filled them again.

[S/V Illusion]

Originally Posted by Oceansailor

I do understand what you say and do agree. The question is if it worse with when it is “empty” but humid. Or if it is better if it is full with water.

This is one of those -there is no single correct answer- questions.

Thinking you can completely dry a tank is wishful. Whether it matters is the better question.

If you are pulling a boat for winter storage in a cold climate, the growth problems in moist closed spaces is minimal.

If you are here in Florida or the Caribbean, keep them full with clean water to minimize growth.

[tarian]

If your pipes are full and tank full there is no o2 for the mold to grow . bacterial infection or viruses must be introduced into the water system so if you know that your water is clean and fresh then you have no issues.
always good to rinse tanks out with a little Milton and flush again and then no issues , people have been using water in all sorts with no issues, the key is keeping the tanks free of contaminants in the first place
Use a charcoal filter , and if really worried about your water a simple UV system after the filter will kill it all off
MILTON>FILTER>UV you could drink piss water with that set up

[sailcrazy]

We've had our boat for 20 years, always in the tropics. We ever we've left her, we always fill the water and fuel tanks to the brim, add a little bleach, and leave them. Water can't condense in the fuel tank if its full of fuel, and while some things could grow in the water, mold and other really bad things can't without exposure to air. And, according to the "Headmistress", the worst part of draining your water system is failing to get ALL the hoses and fittings drained ..and dry..too; moisture in the hoses/fittings will equal mold, etc.. Since freezing is not an issue, we leave everything as full as we can. When we return 6 mo later, we waste that 6-month old water, refill, and waste that water too. Then we refill and use the whole-house filter to catch whatever might still be in the tanks.

[singlespeed]

The only times I faced this issue was when I went on the hard for our annual haulouts in the Eastern Caribbean. I had three separate 40 gallon water tanks on board. I would empty about a third of each tank and dose it with the appropriate volume of bleach for forty gallons of potable drinking water. Then fill the tank with filtered water from the boatyard. Run approximately two gallons of from each tank through any potable faucet on board. This includes the galley faucet, the head faucets, all showers and the heads (if fresh water flushed). Leave the entire system alone until just prior to splashing, the emptying the system by pumping out all the tanks, through all the potable water sources onboard. Either refill all the tanks with filtered boatyard water or wait until your are secure in your new anchorage to fire up your watermaker and start filling your tanks. The residual amount of chlorine left in the tanks with be so diluted as to not be detected by taste.

By leaving the chlorinated water water in the entire potable water system, you will reduce the rate of any growth. Growth will occur in any tank vent. There will be some chlorine gas escaping through the vent throughout the layup; always seemed enough to control the growth in the vent lines. You do inspect the intrusion screen at the vent outlets regularly, right? And don't do what another boater did, when we were in Grenada, and pour chlorinated water into the deck vent, you'll only infect a possibly acceptable tank. Also using anything but clear food grade hose for your vent lines means that the first time you realize that your tank is contaminated is when someone gets sick or the potable water smells. The vent lines breath as the tanks heat and cool throughout the day/night cycle; they provide the first visual indicators that you might be developing a problem.

If your water maker requires chlorine free fresh water for startup, buy a sufficient volume of distilled water (not spring for filtered water) to fire up the system. Distilled water should be chlorine and fluorine free. We had no problems sourcing distilled water in the Eastern Caribbean.

[GB32]

Endorse what Sailcrazy and Singlespeed say.
Works for me on 6 month lay-ups in Malaysia with GRP and Plastic tanks.

____________
The Plan is to make a Plan - if you don't have a Plan how can you change it?

[Dave_S]

I've wondered this as well. My thoughts are without a lot of work you can't completely empty or fill your tanks. I would think a 98% full tank with some chlorine would be better sitting for a while. Then a couple of flush outs when you get back and replace the filters.

I recently removed my tanks, chlorine washed and dried them right out. I also replaced all my lines because there was a smell to the water.

[doublewide]

Empty, full or in between probably doesn’t matter. We have never found our water contaminated after standing in the tanks for 8 months. We generally leave them mostly empty so we start each season’s cruise with fresher water.
Do not put bleach in SS tanks. Bleach will corrode SS. Use Aqua Mega instead.
Aqua Mega tablets purify our water with no tank damage
See this fine study in the subject.
https://www.rdmag.com/article/2014/09/are-your-stainless-steel-surfaces-being-corroded-repeated-bleach-use

[Oceansailor]

Another aspect with stainless is that it needs oxygen in order not to corrode. When the tank is used daily, fresh water will bring oxygen. For long term storage It might that the water is starved for oxygen? Any thoughts on that?

[jen1722terry]

We agree with HelloSailor on the use of hydrogen peroxide. Not as nasty as bleach. We use it to treat our water heater on the summer house that has been drained all winter, and we use it for the boat tanks also. We empty the tanks except for a small amount of antifreeze in the bottom to run through the hoses (our boat winters in Maine).

Also, the advice to put some peroxide in the partially full tanks after storage, pump it through all the water lines, then leave it in the hoses overnight seems to get the taste and odors out of the system.

Cheers!

Terry

[CSY Man]

Good topic.
Somebody mentioned vinegar is better than chlorine for storage: Experts Agree?
I used chlorine for ages. My water tanks have been monel, gelcoat and now plastic on present boat except the hot water tank which is SS.
(On various boats since 1985)

Smell and bad taste, after a Sears filter, has been from the filter housing and from the plastic tubing.
Also had a case of blisters in the fiberglass/gelcoat tank, sanded and prepped, then coated with West System Epoxy which is food grade as per the US Navy: They coat their fresh water tank with West, according to an expert I chatted with.
Smell and taste went away.

Chlorine or vinegar?

[Siberian Sea]

Water tanks empty, fuel tanks full.

[S/V Illusion]

Originally Posted by Siberian Sea

Water tanks empty, fuel tanks full.

Off topic regarding the latter issue but lots of disagreement regarding fuel tank full of old diesel. Diesel doesn’t age well