Uric Acid Crystals in the holding tank

Firefly211

Firefly211

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A couple of weeks ago the pump on the Jabsco was becoming stiff so I stripped it down an renewed the rubbers. What was clear was that there was a lot of uric acid crystals in and around the seals and the bores of the pump base. Suspecting the worst I cleared and rinsed the holding tank this morning to find more solid crystals in the tank. I am guessing the pipes are going to be coated too.

I regularly use Thetford Aquachem as I thought this minimised this sort of thing. I also put some in the loo brush container so that it also has regular doses when the brush is used.

Q - Is there any easy chem solution to flushing out the system and what can I use to stop this happening?
 
I try and encourage people to flush the heads with fresh water before leaving the boat to prevent urine/sea water sitting in pipes.
When I recently took out the holding tank and cleaned it out I was pulling out sheets of salt/crud.
Tek Tanks provided me with some chemical samples. They were pretty good but the volumes we would go through on a school boat makes it impratical. Leesan also do chemicals. Both companies are pleasant to deal with so ring up and have a chat.
 
As you say, their was sheets of the stuff in the holding tank. It the pipes i am concerned about. Will have a chat as suggested.

Anyone know a home brew solution? Vinegar, Bicarb or toilet duck?
 
There have been many threads on this topic, well worth searching. The crystals are usually various carbonates that deposit from seawater on contact with urine. Thick, hard layers are unlikely to be removed by any chemicals in the short term, far better to remove them mechanically, by pounding on plastic tanks with hands, removing hoses and banging them on walls, etc. If the crystals are still soft then chemical methods will work. Hydrochloric acid is best by a long way, followed by all sorts of weak and organic acids.
 
Every time i leave a boat, I pour 1 liter of vinegar in each loo.

Keeps the pipes clean and minimises crystal formation
 
Firefly211 said:
A couple of weeks ago the pump on the Jabsco was becoming stiff so I stripped it down an renewed the rubbers. What was clear was that there was a lot of uric acid crystals in and around the seals and the bores of the pump base. Suspecting the worst I cleared and rinsed the holding tank this morning to find more solid crystals in the tank. I am guessing the pipes are going to be coated too.

I regularly use Thetford Aquachem as I thought this minimised this sort of thing. I also put some in the loo brush container so that it also has regular doses when the brush is used.

Q - Is there any easy chem solution to flushing out the system and what can I use to stop this happening?
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Uric acid crystals I would imagine would be soluble in caustic soda solution, although I have an idea that the sodium salt is not itself all that soluble.

Maintaining a high pH in the holding tank will not be a solution to the problem as that will lead to calcium carbonate deposition as described in the previous replies.

However how do you know your problem is due to uric acid ? How have you identified the crystals as uric acid ?

The more common problem is that of bacterial action on urea producing ammonia which raises the pH causing carbonate deposition.
 
VicS said:
However how do you know your problem is due to uric acid ? How have you identified the crystals as uric acid ?

The more common problem is that of bacterial action on urea producing ammonia which raises the pH causing carbonate deposition.
Click to expand...

To be honest I have no idea what kind of crystals they are and have just assumed uric acid. How do I know if it's carbonate deposition?
 
Firefly211 said:
To be honest I have no idea what kind of crystals they are and have just assumed uric acid. How do I know if it's carbonate deposition?
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Add some to some acid. Hydrochloric acid if you can, an acid descaler or vinegar if you dont have any HCL.

If it fizzes it is almost certainly carbonate, but the reaction with vinegar wont be at all vigorous.
 
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VicS said:
Add some to some acid. Hydrochloric acid if you can, vinegar if you dont have any HCL.

If it fizzes it is almost certainly carbonate, but the reaction with vinegar wont be all that vigorous.
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I work in a school so I will pay a visit to the science prep lab in the morning! Many thanks
 
VicS said:
However how do you know your problem is due to uric acid ? How have you identified the crystals as uric acid ?

The more common problem is that of bacterial action on urea producing ammonia which raises the pH causing carbonate deposition.
Click to expand...

I find it difficult to believe that, in a system which is routinely and properly flushed, uric acid crystals will form "... in and around the seals and the bores of the pump base". Surely for that to happen urine itself would have to be so supersaturated with uric acid that the latter could subsequently precipitate from the very heavily diluted urine residue that might be left in the pump after flushing? I would have thought it is calcium carbonate, formed as you describe.
 
Firefly211 said:
A couple of weeks ago the pump on the Jabsco was becoming stiff so I stripped it down an renewed the rubbers. What was clear was that there was a lot of uric acid crystals in and around the seals and the bores of the pump base. Suspecting the worst I cleared and rinsed the holding tank this morning to find more solid crystals in the tank. I am guessing the pipes are going to be coated too.

I regularly use Thetford Aquachem as I thought this minimised this sort of thing. I also put some in the loo brush container so that it also has regular doses when the brush is used.

Q - Is there any easy chem solution to flushing out the system and what can I use to stop this happening?
Click to expand...

Mens' urinals suffer from yellow crystals in the pipes which can block them - as a result I think of the deodorising blocks which cleaners put in them.
 
garvellachs said:
Mens' urinals suffer from yellow crystals in the pipes which can block them - as a result I think of the deodorising blocks which cleaners put in them.
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When I was working we had this recurring problem with the urinal in the Gents. After a few years of callouts to different plumbers a new chap came.

He told me "All you need to do is stop putting these stupid crystals in the loo, they keep us plumbers in business!!"

We stopped and had no further trouble.
 
Alpha22 said:
Have a read about vinegar......

http://www.pbase.com/mainecruising/vinegar_in_the_head

.... totally useless at clearing pipes in sea toilets.
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Er ... The main author found it did nothing after 4 hours, but one comment below the article said it had worked for him in minutes, and another said that it had worked after leaving it in for 4 months! Too many variables?

If the OP does the test as discussed with VicS, I hope he will come back and tell us the result!
 
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