Guest Derek Uzzell Posted February 16, 2005 Share Posted February 16, 2005 This is an idle curiosity inquiry. Although I understand the basic principles of motorhome 'nautical' toilet systems fitted with fixed waste tanks, I've no practical experience of them. My main interest is whether toilet chemicals actually need to be employed in the waste tank. As far as I can see, when a nautical toilet is used there is little opportunity for odours to enter the bathroom area via the pedestal itself (unlike with Thetford cassette toilets). I presume the fixed waste tank is vented and I would anticipate it's from here that any unpleasant-smelling waste gases might emerge. I notice from Dometic's advertising leaflet for their vacuum-toilet system that mention is made of "an in-line filter that stops malodours from escaping through the vent connection". Is such a filter normal or just peculiar to the Dometic system? With a 'sealed' toilet pedestal and a filtered tank-vent there would appear to be no obvious requirement for chemical treatment of the waste. Even if chemicals were used in a fixed tank, I wonder about their effectiveness for prolonged odour suppression. My experience of 2 adults and a Thetford 20 litres-capacity toilet was that, with regular usage, 3 days was the maximum realistic interval between emptyings and, as disposal time approached, the Nose Test indicated that the chemicals (Thetford Aqua-Kem Green in our case) were definitely flagging. Fixed waste tanks have much greater capacity (Dometic offer tanks up to 90 litres) implying far less frequent emptying requirements - perhaps an interval of 2 or even 3 weeks - and chemicals that become ineffective at 3 days will be well and truly past it after a fortnight. Perhaps RV owners can advise: I don't like being behind the times and I'd really like to get to the bottom of this. Link to comment Share on other sites More sharing options...
Guest Geoff Posted February 16, 2005 Share Posted February 16, 2005 Derek As you obviously did not intend your last sentence to be a pun ! perhaps we had better flush out your motives. I think that I have the best of all worlds with our marine type toilet. It flushes into a holding tank (vented)which with the pull of a lever can emptied into a quite large holding tank. With an outside lever this tank can be discharged directly into the service drain or into a cassette (or several) for disposal in the usual manner. I do not know if it is necessary to use chemicals I have just continued to do so from a habit of many years. I will be interested to hear other views on this and perhaps I can save some money. Link to comment Share on other sites More sharing options...
Guest Derek Uzzell Posted February 17, 2005 Share Posted February 17, 2005 Having visited some USA RV-related websites I note that various chemical waste treatments are being marketed for leisure-vehicle fixed toilet tanks, including a Thetford product named Aqua Kem Supreme Green. Apparently 4ozs of this can treat 40 gallons of waste, and on that basis a half-ounce (2 tablespoonfuls?) should be plenty for your average 17-20 litres Euro cassette. Must be a darned effective chemical given that, for 'ordinary' Aqua Kem Green, Thetford advise a dosage of 75ml per 10 litres of waste-tank capacity. Link to comment Share on other sites More sharing options...
Guest Neal Posted February 18, 2005 Share Posted February 18, 2005 Derek I'll resist the urge to play the pun "game"; my inadequate vocabulary will inevitably cause offence to some! Yes, I use chemicals in my holding tanks (Elsan Blue in the black tank). I am not sure of the capacity of the tank, it's probably about 20 gallons or so, but a cupful of the chemical is all that is required. (I don't actually use a cup, of course, I guesstimate). I use chemicals for a number of reasons: 1. Force of habit, as Geoff has said 2. You will get smells invading the bathroom as there is no water trap. Every time the toilet is used the valve is opened and smells will emerge. The use of chemicals eradicates this. 3. Chemicals break down the waste material and therefore provide an element of cleaning within the holding tank, pipework, dump valves, and dump hose. Some US products, such as TFT, contain additives like coconut oil, which are supposed to lubricate both valves and actual "evacuation". Finally, dumping the tanks without the use of chemicals would be an unpleasant task! Hope this helps. Regards Neal Link to comment Share on other sites More sharing options...
Guest John Posted February 18, 2005 Share Posted February 18, 2005 I have a new German Van with a fixed electric marine toilet. The tank capacity is 180 litres. It is roof vented without a charcoal filter. I was told not to use chemicals and have not do so. There are no smells in the van and no apparent smells outside. Emptying has not been a problem through the 40mm pipe provided, running grey water throught afterwards. Toilet paper is critical so as to not block the macerator. I have wanted to avoid a 'poo paper' bin so use easily degradable toilet rolls. The data on degredation on various makes is on the www. Link to comment Share on other sites More sharing options...
Guest Neal Posted February 18, 2005 Share Posted February 18, 2005 John I hope you never have to deal with your blocked macerator, it ain't gonna be pleasant! Who told you not to use chemicals? Was it written instructions from the converter? From the toilet system manufacturer? Does the system have other means to break down the waste matter, such as SOG? The more the product is broken down, the less trouble you get from the macerator. I believe that the Americans have, by far, the greatest experience in the design, build, and use of marine toilet systems coupled to holding tanks in RV's. If they recommend the use of an additive (chemical) then that's what I'll do. Fragrant regards Neal Link to comment Share on other sites More sharing options...
Guest David Powell Posted February 18, 2005 Share Posted February 18, 2005 The answer is yes use chemicals, Loo Bloo, or what ever. I have no experience of motor home marine toilets, but as some of you know I Narrow Boat on the canals, and naturally all the big ones have marine toilets, and if you don't use chemicals, and pump out at least weekly, the smell will knock a man off his horse. Another problem with marine toilets with a large holding tank is the dreaded Pyramid which can become as well built as the great pyramids of Egypt, so use loads of flush to ensure the chemicals do their job and break everything down. Probably not quite the same as motor home marine toilets Derek, but near enough to take a couple of notes on the subject and draw your own conclusions. Link to comment Share on other sites More sharing options...
Guest Norma Posted February 19, 2005 Share Posted February 19, 2005 Hubby has just explained the pyramid to me. Thankfully that has never happened to us! Then I suppose we move around alot more than a barge. I have certainly noticed a build of gas if we haven't used enough blu, particularly in the summer months. There doesn't seem to be an escape for it - beyond back into the van. And I assume the gas will, of course, expand till it is unloaded. Try to empty as often as poss rather than lug it around. But it sometimes can get difficult. We did try a well marketed organic product. Everything seem to sit on the blade and block the whole system. Where can you buy very long sleeved rubber gloves? Link to comment Share on other sites More sharing options...
Guest Docted Posted February 20, 2005 Share Posted February 20, 2005 Try a Vet Stores Supplier, after all they put their hands all the way up! Link to comment Share on other sites More sharing options...
Guest Ruth Posted February 20, 2005 Share Posted February 20, 2005 As Derek will know from a previous reply we have a Laika with a marine loo, however the waste first enters a holding tank which when full allows you 2 options- empty via cassette or pull a lever and let it into the marine tank. The latter holds a volume equivalent to 3 cassettes worth before it needs to be emptied. We use chemicals for 2 reasons, both mentioned above: 1.If we didn't, smells would enter the van from the first holding tank. 2. The emptying, via either method, would be more unpleasant. I also wonder whether the loo paper would be less likely to biodegrade. At present it seems to - we use the cheap aldi one as it disintegrates well. HTH Regards, Ruth Link to comment Share on other sites More sharing options...
Guest David Powell Posted February 21, 2005 Share Posted February 21, 2005 Hello again Derek..another bit of information which may help your research on this subject. A motor caravanning friend of mine dropped in today for a quick cuppa, read your "fixed toilet waste tanks" and said he had bother with smells coming back up last year. Problem solved by service engineer. His wife preferred quilted toilet paper, which blocked the non-return valve, holding it open. He was advised to use only the correct paper which will desolve[or breakdown]in chemicals. Link to comment Share on other sites More sharing options...
Guest Derek Uzzell Posted February 21, 2005 Share Posted February 21, 2005 Thanks for the replies. I must admit I'd not considered the value of toilet chemicals as a tank-cleaning agent. However, with hindsight, even with relatively limited use (in number of days per year), regular emptying and plenty of rinsing, AND use of a toilet chemical, our Thetford cassette would, over time, build up an impressive layer of scaly deposits inside. Unless periodically removed by citric acid treatment, this scale would eventually cause the rubber seals to start to leak. I presume the same thing happens with large fixed tanks except more so. At the NEC Show I spoke to Dometic about the cassette version of their 'no chemicals needed' vacuum-toilet system and asked how odours were avoided. Like the fixed-tank system, a charcoal-based filter is fitted, this time beneath the cassette itself, and waste gases are vented through the filter (suggested life-span around 3 years) to the underside of the vehicle. I also commented that the capacity (14 litres) of the Dometic cassette compared poorly with Thetford models (17 to 20 litres) and I wasn't swayed by the argument that "Dometic's vacuum-toilet uses less water to flush so the cassette can be smaller". However, as we were about to have lunch, I decided not to risk a disgusted outburst from my squeamish wife and refrained from an in-depth discussion with Dometic's representative on the finer points of motorhome lavatorial etiquette. I'm disappointed that our chatty new pal Gavin (aka Pol Emique) hasn't responded to this posting, as he's clearly keen on the ecological aspects of motorcaravanning (and decidedly full of **** too.) Link to comment Share on other sites More sharing options...
Guest Neal Posted February 21, 2005 Share Posted February 21, 2005 Ooooh, Derek!!!!!!!!!! You bitch! For Gawd's sake, don't start him off again! Link to comment Share on other sites More sharing options...
Guest Clive Posted February 22, 2005 Share Posted February 22, 2005 Regular driving and fast cornering and hard breaking normally overcome the Pyramid problem. Or is that all Po ? Link to comment Share on other sites More sharing options...
Guest brian Posted March 4, 2005 Share Posted March 4, 2005 Ihave a sept 2000 Laika Ecovyp 1r.Problem is the 1st seals leak into the larger marine tank and that leaks onto the ground,obviousely both seals need replacing, has anybody undertaken this task , if so what's the best way to tackle this job and where can I get the correct seals? Incidently I've flushed it out and have been using a thetford toilet but I dont know the manufacturer of the tanks, no help from fiats at all brian Link to comment Share on other sites More sharing options...
Guest brian Posted March 4, 2005 Share Posted March 4, 2005 Ihave a sept 2000 Laika Ecovyp 1r.Problem is the 1st seals leak into the larger marine tank and that leaks onto the ground,obviousely both seals need replacing, has anybody undertaken this task , if so what's the best way to tackle this job and where can I get the correct seals? Incidently I've flushed it out and have been using a thetford toilet but I dont know the manufacturer of the tanks, no help from fiats at all brian Link to comment Share on other sites More sharing options...
Guest brian phillips Posted March 4, 2005 Share Posted March 4, 2005 Ihave a sept 2000 Laika Ecovyp 1r.Problem is the 1st seals leak into the larger marine tank and that leaks onto the ground,obviousely both seals need replacing, has anybody undertaken this task , if so what's the best way to tackle this job and where can I get the correct seals? Incidently I've flushed it out and have been using a thetford toilet but I dont know the manufacturer of the tanks, no help from fiats at all brian Link to comment Share on other sites More sharing options...
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