chemical treatment of unusued holding tank

[hd002e]

I am definitely interested in this. Since I don’t have access to the inside of the tank a chemical solution would be perfect for me. I am overseas and cannot get a hold of this product, would you be so kond to snap a photo of the ingredients/chemical formulation and I’ll try to source it locally. I just hope that whatever acid there is, won’t hurt the fiberglass tank.

Originally Posted by SailingHarmonie

Nonsense. Holding tanks do NOT have to stink. And NEVER inside the boat. Now to be fair, some do, but a categorical statement "that they all do that" is just not true. With good design, and just a bit of care, holding tanks do not make a boat stink. Tolerating a stinky head is NOT a requirement for boat life.

Kind of like a diesel engine. If I go below on a boat and I smell diesel, I know the boat has a diesel engine. If I go below and do NOT smell diesel does that prove that there is no diesel engine? Of course not. It just shows the difference between a well maintained boat and... something else.

Now to be fair, it is probably true that most boats with salt water flushed heads do smell because most boats do not get used nearly enough to flush out the intake lines. In my experience MOST of the times people have a chronic complaint about how their head stinks, it is actually the incoming water that is the problem. Probably not the issue with the OP on this thread, however.

A suggestion to the OP, a tank that has been used for a long time often has a thick coating of hard calcium compounds on the walls. You can flush it with water forever, and these will not come out, and they will retain smell. If you want to clean the inside of the tank without cutting holes, the best solution I know of is "Sew-Clean" (as in "sewer clearer"). It is a formulation of Phosphoric acid and does an exceptional job at this. It is MUCH safer for you and your boat parts than muriatic acid that some people use. Follow the directions exactly, and if the source of the smell is really inside the tank, this is the best way to clean it.

An example of how it works: https://fetchinketch.net/2017/12/26/...th-a-solution/

Nothing but a long term happy customer.

[hd002e]

The rest of the bilge is sparkling clean, the chain locker has a mild seaweed smell but doesn’t get to the v-berth at all.

The holding tank is part of the waterproof bulkhead at the bow and is a thick structural fiberglass tank that is heavily laminated into the hull. I have replaced every single part of the plumbing system (hoses, head, clamps, anti-siphon, valves, deck fitting…) except for the holding tank. I have pressure washed, scrubbed, baking powdered everything around that area and can confidently narrow it down to the inside of the tank. I have no access to the inside and thus I need a chemical solution that is safe for (what I am guessing) is the gelcoat inside the tank.

What chemical would be appropriate?
After the treatment should I leave the tank full of some kind of odor eliminating liquid or empty it out to the best of my abilities and pray for the best?

Originally Posted by peghall

That only means that permeated hoses aren't likely to be source of your odor, but still can be if they're single wall flex PVC (the least expensive). But that doesn't mean the tank is the source. Although very rare, odor can permeate a cheap thin walled plastic tank..the same wet rag test on the outside of the tank will confirm or rule out the tank as the source. A wet bilge in need of a REAL cleaning for a change or a wet dirty shower sump can become a primordial soup that can make a whole boat smell like a swamp or even a sewer. The chain locker is the most overlooked source of odor. Residual odor--odor from previously stink hoses that's attached itself to surfaces in the lockers and passages is another likely source.


So you can keep trying products in the tank if you want to, but your time will be better spent looking for other sources.


--Peggie

[Windpilot]

Look up "Noflex" it's a digester, I'm using it for almost 2 years and think it works great. If you read up on it I think you might agree it's worth a try.
Greg

[Kettlewell]

Nonsense. Holding tanks do NOT have to stink. And NEVER inside the boat. Now to be fair, some do, but a categorical statement "that they all do that" is just not true.

Your quote marks don't quote me! In any case, this is a thread by someone who says his holding tank stinks, so I stand by my actual statement. I've been on many brand new boats at the boat shows that already have holding tank stink.

[colinalleck]

Vetus inspection port

Good luck
Col

[tbeargladd]

You might give this a try




PBW
All-purpose alkaline base cleaner
A friend used it for cleaning the holding tank and water tank. People used it for brewing tanks. Works well.

[merrydolphin]

Originally Posted by Kettlewell

This is one reason I hate holding tanks! You know someone has a holding tank the instant you go below just by the smell of either the tanks or the chemicals they use to mask the odors, and often both. I can smell some of these boats as I dinghy past them or walk around the boatyard. Sure, follow Peggy's best practices and you can eliminate most of the problem, but in my experience for whatever reason most boats with holding tanks just stink.

I agree. I hate holding tanks, and the whole BS about their need. When I was anchored in Trinidad, the Government did a serious study on pollution from the HUNDREDS of cruising boats anchored there. The vast majority didn’t have holding tanks. The study showed that the e-coli count was minimal except for a specific event………….RAIN. Whenever it rained it went way up! Yes, run-off from the land! If you have good movement of the water, the one or two turds ( and they exit the boat broken up), that you pump into the water rapidly disipates. 99.9% of water pollution comes from shore run-off and outlets.

Us disorganized unrepresented boaters do make great scape goats, as municipalities pump hundreds of cubic yard per minute. (one yard cubed is 202 gal). And no, it’s not all nicely treated. (Believe that and I have a bridge to sell you). Once you leave the US, good luck finding any pump outs in most of the world. And for the privilege of these holding tanks, that you now have little use for, you get a permanently stinky boat. And once it permeates the boat it is really hard to ever get rid of. I have seen a number of boats where the smell had permeated the wood work. Sooooo, I have gone to composing heads and love them. And NO smell! Plus you eliminate holes in the bottom of your boat that clearly have the potential to sink you. ( and many boats have sunk due to head issues).

Now if you live in an inclosed body of water. Eg a lake or inclosed marina with very little water moving, then you do need either holding tanks, or composting.

[Iron E]

Originally Posted by peghall

A wet bilge in need of a REAL cleaning for a change or a wet dirty shower sump can become a primordial soup that can make a whole boat smell like a swamp or even a sewer. The chain locker is the most overlooked source of odor. Residual odor--odor from previously stink hoses that's attached itself to surfaces in the lockers and passages is another likely source.


So you can keep trying products in the tank if you want to, but your time will be better spent looking for other sources.


--Peggie

This.

I was doing some work this weekend and removed the galley sink hose for better access. The water in the hose spilled into the bilge and the immediate smell floored me (My wife gave me a look like I tried to sneak one out)

Though it smelled like sewage, it definitely wasn't. It was something that brewed from sea life from the through hull mixed with whatever was rinsed in the sink.

[Bowdrie]

On a lighter note.
I see you're in the Eastern Med? If so, can you get a few gallons of cheap red wine?
Pour it in the tank, go sailing so it gets sloshed around a lot and then pump the tank out.

Should make any leaks easy to find.
Just saying.

[merrydolphin]

Originally Posted by Iron E

This.

I was doing some work this weekend and removed the galley sink hose for better access. The water in the hose spilled into the bilge and the immediate smell floored me (My wife gave me a look like I tried to sneak one out)

Though it smelled like sewage, it definitely wasn't. It was something that brewed from sea life from the through hull mixed with whatever was rinsed in the sink.

Nothing, and I mean nothing smells holding tank but a holding tanks and it’s peripherals. Yucky bilge, sink drains all have there smell but holding tanks permeate a boat and soak in to everything. Like someone said some you can smell as you approach for the water/dock. And it’s unmistakeable.

[peghall]

Not quite true. A wet dirty bilge or sump is a "primordial soup" that can make an entire boat smell like a swamp or even a sewer. Residual odor left behind in lockers and passages after a leak or spill or stinking hoses have been replaced are another source. Chain lockers in need of cleaning are the most overlooked source. I devoted an entire section of my book to "Boat Odors Aren't ALL in Your HEAD."


--Peggie

[sailorboy1]

Originally Posted by Kettlewell

I've been on many brand new boats at the boat shows that already have holding tank stink.

must be you then because rarely do I go onto a boat that has holding smell and I notice smells very easy

[peghall]

Sorry I omitted to mention that every single hose and head component, valves, deck plate etc has been replaced. So my source is inside the tank.


I doubt that. It's either residual odor left on all the surfaces, nooks and crannies including the outside of the tank by the previous stinky hoses or there was a previous spill which often happens when a hose or maybe a macerator pump is disconnected.

The cure: You cannot eliminate any odor unless you first eliminate its source 'cuz as long as the source continues to exist it'll continue to generate odor. So first you need to scrub every surface, nook and cranny including the outside of the tank using a strong solution of detergent and water (Dawn Ultra is good for this)... NO bleach.

When everything is just damp dry, treat every surface nick and cranny including the outside of the tank with a product called PureAyre, which you can buy from Amazon (not sure where you are but Amazon (dot wherever) should have it....their "household" version will work just fine for this. It's not an air freshener, It's the only product I've found that eliminates ANY odor when used according to directions.. Not only will it get of diesel and residual odor left behind by stinking sanitation hoses, but PureAyre is also rated for use around food...which means you can even use it to get rid of the odor left in your fridge by the steaks or fish that spoiled when a natural disaster took out shore power for 3 days. Also does a great job on musty PFDs and foulies..

How to use it:
Use PureAyre full strength...I'd use a pump garden spray jug set to a fine mist. Spray every surface, nook and cranny and the outside of the tank...just a light spray. Do NOT rinse...just let it dry with hatches open so that plenty of fresh air can circulate for 24 hours. If the soft goods in the cabin have picked up the odor, just spraying it on the surface won't do much...you need to spray enough on carpets and rugs to penetrate to the backing...enough to penetrate cushions to the middle from both sides..not enough to make 'em drippy, just enough to get into the cushion....you'll prob'ly have to remove the covers and send 'em to be cleaned. Again, just let everything dry. If you still have any odor, you missed a spot.

A spray bottle won't go very far...plus, it's cheaper in the long run to buy it by the gallon to use as needed. Just remember to store it in a cool place


--Peggie