alternate toilet chemicals

Submitted: Wednesday, Dec 17, 2014 at 08:39
ThreadID: 110444 Views:2960 Replies:8 FollowUps:5
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Hi all, have looked at the blogs on this, any advances on the suggestion of using napisan solution or similar in bottom tank as an alternate to commercial products? ( 34% Sodium percarbonate). do members think this is 'green' safe and economocal method to use and what about top chemical at all?. on the road for 6/12.
PS: thanks to mother hen for blog .

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Reply By: Member - mike g2 - Wednesday, Dec 17, 2014 at 08:51

Wednesday, Dec 17, 2014 at 08:51
Me again, have looked more into other posts and articles- i think have managed to answer own question now!. quite a few items on napisan or equivalent bieng ok.
AnswerID: 543073

Reply By: Peter_n_Margaret - Wednesday, Dec 17, 2014 at 08:54

Wednesday, Dec 17, 2014 at 08:54
Nothing in the top tank.
Sodium percarbonate is setic safe and "green".
Do not use too much. That is counter productive.
We use one teaspoon full per #2.

This was written by Frans Harmer, fill time on the road and semi retired industrial chemist.

"Sodium percarbonate is also known as Sodium Carbonate Peroxide (PCS) which is probably a better general description and its chemical name is Sodium Carbonate Peroxyhydrate.

Its chemical formula is (Na2CO3)2(H2O2)3and as you can see there is a fair bit of oxygen there. Pure sodium percarbonate contains about 13% oxygen.

It is the product used in all those adverts you see for various products supposedly “oxygenated” and have that miraculous “oxi” or “oxy” action which includes those washing powders we put into our washing machines and where applicable into the septic systems.

The misunderstanding about PCS is the fact it is promoted as a bleach even if it is an oxygenating bleach.

We have all been brought up to consider bleach as evil in some regards. Unfortunately, this “bad bleach” is chlorine based like the stuff we throw in swimming pools to kill the bad bugs and if introduced into septics, it kills the good bugs. Formaldehyde which is contained in some of the chemicals for toilet casettes is also in this category.

So the problem here is the general reaction by those not knowledgeable in the difference, see the products containing PCS as a bleach meaning it is bad which is the opposite to the facts.

Just to clarify to some who may have seen other names for oxygenating bleaches, there are 3 types of oxygen bleaches generally available - hydrogen peroxide, sodium percarbonate (which we shall continue to abbreviate as PCS) and sodium perborate.

If we understand how PCS works, we can see why they are not at all harmful to septics.

Those familiar with common chemical compounds will see that PCS essentially contains sodium carbonate and hydrogen peroxide stuck together. It is made by treating natural soda ash with hydrogen peroxide and the oxygen is absorbed while remaining a free flowing solid.

Upon dissolving in water, it breaks back down into natural soda ash after the oxygen is released. The oxygen is used up in your toilet cassette breaking down the stuff that is in there, and you are then left with the soda ash which can do no harm to any septic.

Now let’s turn the argument around from why is PCS not harmful to septics to what can there be to harm a septic system.

When PCS is broken down we have sodium carbonate which has a higher than neutral pH. Septic systems will fail at lower pH and require higher levels to stay efficient. The septics that smell usually have an acidity problem which is killing off the bugs. A means of correcting this is to raise the pH by the addition of lime. Sodium carbonate has a similar effect, however the comparatively minute amount we are putting into a septic will really have no effect, but if it does it will be positive.

In fact it is recommended that bicarbonate of soda (sodium bicarbonate) is used as a cleaner for septics. Sodium carbonate (the left-over from PCS) has the same chemical effects as Bicarb so that can not harm the septic.

The usefulness of PCS in our use is the generation of oxygen. The basic septics are anaerobic and this could be one of the reasons for the misconceptions about using PCS products with septics if there is an assumption that the oxygen will ruin a septic.

This argument also doesn’t stand up to scrutiny. Firstly, we are using a teaspoonful per day which let’s face it is bugger all. At that rate, all the oxygen will be used up trying to cope with the stuff in the toilet, so by the time we dispose of it there will be no free oxygen and even if there was, there would be nowhere near enough to adversely affect a septic.

Secondly, the same would apply to all those “Oxy” washing powders and cleaners (all PCS) which are all OK for septics and if anything, would deliver more free oxygen than our cassette or black water tank.

Thirdly, although septics are an anaerobic system, they are unaffected by the introduction of a little oxygen. Aerobic systems require the introduction of oxygen. Anaerobic systems do not require oxygen and work best without it. This does not mean that a little oxygen will kill it.

So if anybody with a septic believes that the PCS products are bad, they will need to stop using most of the modern day "safe for septics" PCS bleaches, cleaners, dishwasher powders, washing powders etc.

By all means use the generic nappy treatment products if they say they are septic safe on the labels.

Where can there be a problem with these products? Only where there are other compounds in there which are not septic friendly so it is important to read the label to make sure the one you use is OK for septics.

Because the oxygen is released as soon as it is dissolved in water, I would suggest a teaspoon of the powder per day directly into the toilet. It will release the oxygen a little more slowly.

Keep in mind it will be absolutely useless if you only pee in the toilet - you will need to use something else.

By the way, do you know why they are called septics? Simply, because they are septic. They are full of Eschericia coli (e-coli lives within our large intestines in a symbiotic relationship with us as it is a source of vitamin K). So, anaerobic systems are "septic" (meaning contaminated with microbes) and must be isolated from surface water and well aquifers and is a reason you can not locate your septic trench near a stream or underground water supply."

OKA196 Motorhome.
AnswerID: 543074

Follow Up By: SuperGrover - Wednesday, Dec 17, 2014 at 18:32

Wednesday, Dec 17, 2014 at 18:32
Keep in mind it will be absolutely useless if you only pee in the toilet - you will need to use something else.

We only use ours for this purpose. Any recommendations for a suitable product for urine only?
FollowupID: 829971

Follow Up By: Bigfish - Wednesday, Dec 17, 2014 at 19:27

Wednesday, Dec 17, 2014 at 19:27
I was about to say the same thing

Very informative.
FollowupID: 829977

Follow Up By: Peter_n_Margaret - Wednesday, Dec 17, 2014 at 21:17

Wednesday, Dec 17, 2014 at 21:17
Google SOG for RV toilets.
It is a fan that sucks air through from the bowl to the outside when the flap is opened. There is a carbon filter on the outlet to absorb smells to protect the neighbours too.
Also works well for 'normal' use and some people are happy to use no chemicals if an SOG is fitted.

OK196 Motorhome
FollowupID: 829980

Follow Up By: SuperGrover - Wednesday, Dec 17, 2014 at 22:27

Wednesday, Dec 17, 2014 at 22:27
Thank you I looked at the SOG for RV toilets site and it looks interesting but I would not like to cut all those holes and go to all that trouble for something that I have not heard of being used much here in Australia. I am happy to try different treatments to add to the water which I can just wash out if I do not like it. I was wondering why I was not having much success with napisan for my use. Thanks again
FollowupID: 829983

Reply By: Grumblebum and the Dragon - Wednesday, Dec 17, 2014 at 09:15

Wednesday, Dec 17, 2014 at 09:15
A very erudite explanation for the uninitiated - well done Peter
AnswerID: 543075

Reply By: Member - John and Val - Wednesday, Dec 17, 2014 at 10:47

Wednesday, Dec 17, 2014 at 10:47
Thanks Peter for posting that explanation by Franz Harmer - should lay to rest any misconceptions about how Napisan and similar products work, and why they wont harm septic systems. Also confirmed a long standing practice of ours to occasionally flush some lime into our septic system - works a treat to stop any smells. Frustratingly, many councils and commercial operators advocate regular pumping out of septic systems, something that is not necessary at all if the system is working properly - a triumph of commercial hype over basic science (chemistry and microbiology)! Our septic has been going for about 35 years and has never been pumped. And we have found that Napisan works very well in a potra-loo.


J and V
"Not everything that can be counted counts, and not everything that counts can be counted."
- Albert Einstein

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AnswerID: 543079

Reply By: Notso - Wednesday, Dec 17, 2014 at 12:20

Wednesday, Dec 17, 2014 at 12:20
The thing with the percarbonates is that they only work whilst there is free oxygen. Putting organic matter into the toilet creates what is termed "the biological oxygen demand". This organic matter to put it nicely uses up the oxygen this kills odours etc. But, when all the oxygen is used up then there is nothing left to break down odours etc so the tank can get quite smelly very quickly.
AnswerID: 543082

Follow Up By: Motherhen - Wednesday, Dec 17, 2014 at 23:58

Wednesday, Dec 17, 2014 at 23:58
With Sodium Percarbonate powders it is easy to add a little each day to keep it active.


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Reply By: Hoyks - Wednesday, Dec 17, 2014 at 18:53

Wednesday, Dec 17, 2014 at 18:53
I use the cheap black and gold nappy treatment product. It is a fraction of the cost of the named brand, yet has the same active ingredient in the same concentration.

It doesn't smell as nice, but after I crap on it, anything is an improvement.

In the top tank, just water. In the bottom I put a 1/4-1/2 cap of the powder and about a liter of water. For No.1 a deserving tree was usually selected so the port-a-potty didn't get over used.

The toilet bounced around for a few days in the back of the ute before getting emptied and was not anywhere near as offensive as I thought it would be. Paper and No.2 formed a none too attractive slurry that hosed out and had hardly had any odour to speak of.
AnswerID: 543093

Reply By: Slow one - Wednesday, Dec 17, 2014 at 20:25

Wednesday, Dec 17, 2014 at 20:25
We have been using this formula that was suggested by someone on a forum with very good results.

40ml of 34% Sodium percarbonate for 1 litre of water and add 1/2 teaspoon of Citric acid + 1/2 teaspoon of euclyptus oil in the bottom tank.

Have found this works very well and is much better than just using the percarbonate by itself.
AnswerID: 543097

Reply By: Motherhen - Thursday, Dec 18, 2014 at 00:02

Thursday, Dec 18, 2014 at 00:02
No additive at all is fine if

1. You fit a SOG
2. You have a vacu-flush toilet
3. you empty daily or at least every two days.


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AnswerID: 543106

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