holding tank, best way to rinse it out

[simonfraser]

not sure how bad the deposits are in the holding tank, but what can i pour into the heads to rinse the tank out ?

will be out at sea when i use the heads in the future

 

[Megs20Burt!]

We use water softener for the holding tank which we understand prevents solids build-up and bicarbonate of soda if leaving the boat unused for sometime. As we are inland, not much choice other than use pump-out.

 

[simonfraser]

tnx

 

[Mistroma]

Our tank is translucent with a back light. It just shows a dark shadow for the level but the tank sides are clearly visible when empty.

There are a small number of little patches on the tank wall but it is mostly clear after >10 years regular use. I give it a rough clean after emptying but partly filling with salt water and a proper clean at the end of each season. The latter involves a fill with some hydrochloric acid dissolved in fresh water and left for about 12 hours before emptying and refilling with salt water at sea. I repeat with caustic soda and fresh water and give it a last fill with fresh water the night before lifting out. The tank is emptied en-route to the boatyard a few miles away.

I also put a little hydrochloric acid through the bowl every 6 weeks or so. Probably overkill but it does seem to work and I don't have any build up in tank or the pipes. It also helps that I always flush extremely well after peeing, not possible in harbour of course as the holding tank capacity is a limiting factor.

Hydrochloric acid will dissolve calcium salts but you'd end up using a huge amount on a badly coated system. It works well if you keep on top of it. The caustic soda just softens "organic" material and helps reduce material sticking to the tank wall but won't move any calcium related deposits.

 

[longjohnsilver]

I also use a little brick acid very occasionally to keep the pipes clear. And absolutely agree that flushing the loo with plenty of water definitely helps prevent the lime scale in the first place. A well known ex poster, jfm recommended using dissolved dish washer tablets which I’ve done. I assume it helps, the theory seems sound. Nothing to lose by trying.

 

[Momac]

I have been using Ordourlos this year as opposed to Elsan Blue previously .
Elsan is toxic / carcinogenic .

Just a measured dose of Odourlos is added via the toilet after each emptying of the holding tank. I cant see into the tank but there are no smells and noticeably no smell when pumping out , seems better than with Elsan.

We had a while with no tank additives before starting with the Ordourlos
Adding acid or bicarb or other tank additives would kill the enzymes .

We do pump out on the river (while on the move , not at a mooring) as it is permitted.

 

[BruceK]

I've always avoided any chemicals. Instead I try and promote a healthy bacteria colony that breaks everything down. It's always with some dismay at the beginning of the season after a winter on the hard that the colony is dead and the black tank stinks. A couple of weeks and it finds harmony again. If any of you ever had a french drain system you'd appreciate those bacteria.

 

[Boater On Thames]

We do pump out on the river (while on the move , not at a mooring) as it is permitted.

This scares me! What river are you in?

 

[Momac]

Why does it scare you ?
On the Thames you are prohibited by a bylaw. Even so it would be foolish to swim in the Thames .

Exclusive: water firms discharged raw sewage into England's rivers 200,000 times in 2019

Other than where a bylaw is in place the discharge of sewage from a vessel is specifically excluded from prohibited activities.

The Environmental Permitting (England and Wales) Regulations 2016

UK Statutory Instruments
2016 No. 1154
SCHEDULE 21
Paragraph 3
Meaning of “water discharge activity”


3.—(1) A “water discharge activity” means any of the following—



(a)the discharge or entry to inland freshwaters, coastal waters or relevant territorial waters of any—


(i)poisonous, noxious or polluting matter,


(ii)waste matter, or


(iii)trade effluent or sewage effluent;


(b)the discharge from land through a pipe into the sea outside the seaward limits of relevant territorial waters of any trade effluent or sewage effluent;


(c)the removal from any part of the bottom, channel or bed of any inland freshwaters of a deposit accumulated by reason of any dam, weir or sluice holding back the waters, by causing it to be carried away in suspension in the waters, unless the activity is carried on in the exercise of a power conferred by or under any enactment relating to land drainage, flood prevention or navigation;


(d)the cutting or uprooting of a substantial amount of vegetation in any inland freshwaters or so near to any such waters that it falls into them, where it is not reasonable to take steps to remove the vegetation from these waters;


(e)an activity in respect of which a notice under paragraph 4 or 5 has been served and has taken effect.


(2) A discharge or an activity that might lead to a discharge is not a “water discharge activity”—



(a)if the discharge is made, or authorised to be made, by or under any prescribed statutory provision, or


(b)if the discharge is of trade effluent or sewage effluent from a vessel.



(3) In determining whether a discharge or an activity is a water discharge activity, no account must be taken of any radioactivity possessed by any substance or article or by any part of any premises.

 

[Portofino]

Serviced the three macerators a few years back did not notice any calcification.We use what ever supermarket proprietary toilet cleaner diluted every flush .This keeps it fresh for the next user and effectively drip feeds the tank contents .
Its discharged running way out at sea .
In the winter I crush a dissolvable bleach tablet and flush that in .
This sumner I changed / re routed the vent pipe .Tank is twixt engines in the middle of the V in the ER .You stand on it .
After pulling it off not surprisingly there was minimal odour .

Previous boatload a vacuflush system ( horrible system ) that did scale up and required it’s Y valves dismantling , scraping out cleaning with acid , etc and knackered duck beak valves replacing etc .Yes the white pipes went hard as the scale accumulated.

The difference I can think of is this current boat has a macerator on each bowl .Not sure why this effect and a little aeration while it’s chopping the contents up every flush prevents this scaling up of the white pipes .
Every other variable is identical.