descaling holding tank - how?

[vyv_cox]

Virtually every de-scaler is harmful to the aquatic enviroment. As they are normally some sort of acid. AFAIK.

The good thing about using hydrochloric acid for this purpose is that its reaction products are mostly calcium chloride, water and carbon dioxide, none of which could be called harmful to the environment. Not too sure about the sulphamic acid, which is H3NSO3, presumably the reaction products are some combination of calcium sulphates, nitrates, water, CO2? No doubt Vic will tell us.

However, the main point is that using these products until they have reacted and then releasing them is not particularly harmful.

 

[pmyatt]

Every year, when ashore doing our annual maintenance, we close the heads inlet sea cock and then pump a couple of gallons of vinegar into the pipes and holding tank and leave it until we go back in the water - seems to work - both tank and pipes remain smell-free and the hand pump continues to operate freely.

 

[PetiteFleur]

I recently spotted some old-fashioned "Spirit of Salts" in my local hardware shop, and used it on a lime-scale encrusted domestic installation. Highly effective, but with alarming gurgling noises and acrid fumes. Don't know what's in it but it's clearly acidic, so I should check on its ingredients in view of the preceeding warnings.

'Spirit of Salts' - we have some and your post prompted me to get SWMBO to find it and have a look - it is marked 32% Hydrochloric Acid.

 

[nimbusgb]

I have used Dilute sulphuric acid to 'decoke' home porcelainware.

Where do you get it from? Easy the local battery installed has huundreds of dead batteries in a box around the back. A bit of sweet talking and .....

 

[ksutton]

Would this work?

http://www.wickes.co.uk/Brick-and-Mortar-Cleaner/invt/153779

 

[nimbusgb]

I think you'll find that the brick cleaner is diulute HCl

 

[BobnLesley]

De-scaling

Since arriving in Turkey we've discovered Pur Coz (Pu-ah Juice) which cleans and de-scales everything; it also leaves your fingers (gloves are for wimps!) a strong orangey-yellow colour, so I'm presuming that it's Nitric Acid based? It's certainly powerful stuff!

 

[mike489]

Pressure washer

We have had holding tank problems previously, and have come up with a number of solutions. The best one (least messy)is using the deck pump out facility so the easiest way to shift a blockage seems to be to 1) block the breather, 2) apply the pump out facility with the seacock closed, after 20 secs or so open the sea cock. This usually results in a great intake of water and the blockage is no more - keep the pump out running fresh water through the tank for a while.

Having read up on holding tanks it seems that they should be regularily cleaned. We use our pressure washer, which has a drain cleaner attachment. we thread the drain cleaner attachment into the tank then run the pressure washer with the seacock closed. Empty tank and repeat until the amount of white scale is nearly non-existent.

And finally we now NEVER put loo paper through the holding tank, it seems to be asking for trouble.

Since doing the maintainence twice yearly and stopping the Loo paper, the tank has been much better.

(If you don't have a deck pumpout it is possible (but not very pleasant) to thread the drain cleaner through the outlet seacock. (If you don't have a diverter valve).

 

[Bobobolinsky]

I recently spotted some old-fashioned "Spirit of Salts" in my local hardware shop, and used it on a lime-scale encrusted domestic installation. Highly effective, but with alarming gurgling noises and acrid fumes. Don't know what's in it but it's clearly acidic, so I should check on its ingredients in view of the preceeding warnings.

It's the apothecary's name for hydrochloric acid. Can't see that using it on a low pressure header is going to cause much damage as long as it is flushed out well. As has been said it can cause cracking when under pressure. Stainless pressure vessels are tested with water with less than 29ppm of chlorides. Basically though it means no testing with sea water. Have had to get water brought in in tanks where desal/ro was not acceptable