toilet build-up

scoty

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I have a lav vac system and have tried lots of chemicals,,,those that I think will not harm my blakes sea cocks, BUT nothing so far stops a build-up of scale,
No paper is ever used, as the toilet is only used in emergency for peeing,

any suggestions to keep the pipes clear,
 
It's called urine scale and can be removed with strong acid. Vinegar won't do the job!
Either buy a dedicated urine scale remover or get some hydrochloric acid.
 
Sounds like it is not being pumped enough to completely clear the waste pipework after use.
 
Urine reacts with seawater to form the scale deposit. Look at the size of the pump and compare to the size of the waste pipe you need to completely flush the urine. Typically 20 strokes of the pump is a minimum, and may be more.
 
Vinegar worked on my heads through-hull.
It was completely blocked with scale and jammed so I used a softwood bung at the outlet end and filled with seacock with Sarsons malt. It foamed up right away but I left it for a couple of days, topping up now and again.
It got rid of the scale and the ball valve now works perfectly.
There is a low foaming marine toilet cleaner which contains phosphoric acid which works fine to prevent scale building up. I bought two bottles of NATO labelled stuff from a market trader years ago... it might be worth a Google.
 
Lee Sanitation do some good stuff that keeps the pipes clear and doesn't rot your rubber. It's called Leescale and you can buy it from them on line. I dose our Lavac system with it from time to time and it works for us. The occasional flush through with warm soapy water helps, as does the trick of priming the system with fresh water if you are leaving the boat for a while. With the Lavac just pump through with the lid up and then add fresh water and pump through until the system is full. Prevents nasty niffs when you return as well. Even so, it is worth an annual check of the Lavac pump and its valves, especially the joker (exit) valve which can deteriorate quite quickly and allow run back into the bowl. You can replace that valve with the pump in situ, but the inlet requires the unit to be taken off and split.
 
Just a word of caution. De- scaling should be done regularly (say once a month). If you leave it to build up then the Hydrochloric Acid can liberate large chunks of scale which then block the outlet valve.....the rest is history!!!!

I put Hydrochloric acid down as you say once a month, however if you are in the water how does it stay in the bits that you need it to, namely the bottom 1 ft of the pipe? Do you pump it through and mid pumping shut off the outlet valve?

What concentration should the acid be? Do you know what it is called in Greece - its all dutch to me out there!
 
I put Hydrochloric acid down as you say once a month, however if you are in the water how does it stay in the bits that you need it to, namely the bottom 1 ft of the pipe? Do you pump it through and mid pumping shut off the outlet valve?

What concentration should the acid be? Do you know what it is called in Greece - its all dutch to me out there!

Hi Chris,

I buy the stuff on sale in most of the supermarkets, Proton seems to keep quite strong stuff. Don't dilute it, just as it comes. Pump out the bowl as far as possible, then pour in a 500 ml bottle and pump about three times. You will hear the bubbling as CO2 is released. When this dies down a bit, pump three times again. Keep going in three-pump cuycles until it is all gone. Add another bottlefull if it seems to need it. I usually use about 1 litre every three or four weeks.

I can't think of any way to react the deposits on the downstream side of the loop but my observations are that enough acid seems to get there that deposits are light.
 
I continue to be astonished by these toilet posts! I replaced my 20 year old outlet seacock this year, which involved also replacing part of the outlet pipe. The pipe had never been removed in 20 years. Strangely, it wasn't full of crud. I can't explain why this should have been the case. I never use acids to clean the pipework, but the outlet pipe is quite short, and I always insist on copious flushing of the toilet. Maybe flushing is the secret?
 
So, Vic, is it true that all these people with toilet problems simply don't flush enough seawater through? Is it that simple? We hear these stories of people taking pipes out and bashing them on the pontoon to get the crud out. Surely, if flushing were the answer, people would be doing it?
 
It probably does not need an awful lot of nitrogenous waste left in the pipes to cause the problem.
My understanding it that the bacteria get to work on it producing ammonia, that raises the pH, and neutralises, if that is the right word, the "bi" in the bicarbonte (the hydrogen in hydrogen carbonate to be more scientific) with the result that calcium carbonate is deposited.

If you flush away all the waste that causes the problem you wont get any scaling but I guess no one wants, or expects, to spend 30 seconds peeing and several minutes pumping. Result scaled pipes.

My bucket doesn't seem to get scaled :D
 
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