Deionizer or regular water filter?

fdonadio · Nov 13, 2015

I have some problems with tap water in my city. Chlorine levels are so high that, sometimes, you can smell it or taste it in the water.

There are some filters available for around 30 USD that claim to eliminate 85% of free Cl. Besides that, these filters will eliminate 75% of solid contaminants.

For around 110 USD, I can get a deionizer that claims to eliminate soluble salts, metals and free Cl.

I thought I wouldn't need to buy distilled water if I got the deionizer, but I am not sure.

Should I go for the deionizer or the regular filter will do?

Simon Howers · Nov 14, 2015

Reverse osmosis

I suggest a 'reverse osmosis' filter. These are available for a reasonable price at aquarium shops. A typical filter, once setup properly, will deliver water containing no more than 10ppm dissolved solids - which is fine for photographic chemistry. You can keep fish as well!

I used one of these devices when I lived in London where water quality is terrible - there is so much chlorine in the water that a bath looks green!

Good luck

Simon

RobC · Nov 14, 2015

If you get an inline deioniser for your darkroom water supply it will take out nearly all the minerals. I'm not sure they take out chlorine though.
However, boiling water for a few minutes will evaporate off the chlorine.

Ian Grant · Nov 14, 2015

RobC said:
If you get an inline deioniser for your darkroom water supply it will take out nearly all the minerals. I'm not sure they take out chlorine though.
However, boiling water for a few minutes will evaporate off the chlorine.

They take out all the chlorine.

On a small scale the Britax (or similar) water filter jugs are sufficient, we have to filter our water here where we live in the UK as it has a very high calcium content and that also removes the chlorine.

Ian

RobC · Nov 14, 2015

one of these then...

http://www.coleparmer.com/Product/M..._housing_3_4_NPT_or_3_8_hose_barb/EW-01503-20

fdonadio · Nov 14, 2015

Thanks, all of you guys. Great answers. So, the deionizer seems to be the choice for me.

fdonadio · Nov 14, 2015

Simon Howers said:
I suggest a 'reverse osmosis' filter. These are available for a reasonable price at aquarium shops.

Well, depends on what one considers "reasonable". The cheapest ones available here cost close to 500 USD!

But thanks for the suggestion. I am still going to take a closer look at these.

Wayne · Nov 14, 2015

I don't know which deionizer you're looking at but the one linked to above has a flow rate of only 15 gph.

fdonadio said:
I have some problems with tap water in my city. Chlorine levels are so high that, sometimes, you can smell it or taste it in the water.

There are some filters available for around 30 USD that claim to eliminate 85% of free Cl. Besides that, these filters will eliminate 75% of solid contaminants.

For around 110 USD, I can get a deionizer that claims to eliminate soluble salts, metals and free Cl.

I thought I wouldn't need to buy distilled water if I got the deionizer, but I am not sure.

Should I go for the deionizer or the regular filter will do?

fdonadio · Nov 14, 2015

Wayne, thanks for the heads up! I'll pay attention to this...

Gerald C Koch · Nov 14, 2015

If the water is safe to drink, and I am sure it is, then the chlorine level is not a concern. The smell of chlorine is detectable at very low levels by its smell. In addition any sulfite present in developers and fixers will react with chlorine and convert it to chloride ion.

Wayne · Nov 14, 2015

Gerald C Koch said:
In addition any sulfite present in developers and fixers will react with chlorine and convert it to chloride ion.

the significance of which is probably obvious to you, but not to the rest of us idiots.

fdonadio · Nov 14, 2015

Gerald C Koch said:
If the water is safe to drink, and I am sure it is, then the chlorine level is not a concern. The smell of chlorine is detectable at very low levels by its smell. In addition any sulfite present in developers and fixers will react with chlorine and convert it to chloride ion.

Yes, it is safe to drink. My main concern is using this water to dissolve developers and other photo chemicals.

I have always believed that distilled water is the best option, but one has to go out and buy it. A distiller is way too expensive and wastes lots of water. I thought a deionizer would be an acceptable solution for this problem.

fdonadio · Nov 14, 2015

Wayne said:
the significance of which is probably obvious to you, but not to the rest of us idiots.

I understand that as "free Cl is not a serious problem". But I might be wrong.

georg16nik · Nov 14, 2015

fdonadio said:
Yes, it is safe to drink. My main concern is using this water to dissolve developers and other photo chemicals.

I have always believed that distilled water is the best option, but one has to go out and buy it. A distiller is way too expensive and wastes lots of water. I thought a deionizer would be an acceptable solution for this problem.

Cheapest steam distillers cost ~ $100US and is low maintenance - some citric acid once in a while.
The monobed deionizer with max capacity 700 grains CaCO3 suggested above is $141US.

Wayne · Nov 14, 2015

That seems like a logical interpretation.

fdonadio said:
I understand that as "free Cl is not a serious problem". But I might be wrong.

walliswizard · Nov 14, 2015

I use battery top-up water from the local motorist centre. Very cheap. That's deionized, seems fine for what I need.

Gerald C Koch · Nov 14, 2015

A very simple and cheap solution is to boil the water for a couple of minutes. Any dissolved gases like chlorine will be expelled. This method will also remove any temporary hardness from the water. Let it stand overnight and then either filter or decant it from any solids.

Роберт · Nov 15, 2015

Exactly, and the most oxygen (gas) is also out then. Much better when making a developer from this "photo" water.

fdonadio · Nov 16, 2015

georg16nik said:
Cheapest steam distillers cost ~ $100US and is low maintenance - some citric acid once in a while.
The monobed deionizer with max capacity 700 grains CaCO3 suggested above is $141US.

I've searched a lot and didn't find steam distillers for sale here in Brazil. Strange, but... Go figure!

I can get deionizing filters for under $100 US here. These have a very low flow rate, though. The better ones cost between $100 and $150.

Reverse osmosis filters are pretty expensive. Simple 3-stage, 10 gallons/day filters cost over $400 US without a pressurizing pump (over $100 extra)!

From what I've read, RO filters are suitable substitutes for distillers. Chemists on duty, please confirm this!

fdonadio · Nov 16, 2015

walliswizard said:
I use battery top-up water from the local motorist centre. Very cheap. That's deionized, seems fine for what I need.

Wallis, that is sold here in Brazil as "distilled water". It's very cheap indeed.

As I said, my main concern is the need to go out and buy water when I need to mix chemicals – usually at 10pm, in the city I live in, this would be an impossible mission!

fdonadio · Nov 16, 2015

Gerald C Koch said:
A very simple and cheap solution is to boil the water for a couple of minutes. Any dissolved gases like chlorine will be expelled. This method will also remove any temporary hardness from the water. Let it stand overnight and then either filter or decant it from any solids.

Роберт said:
Exactly, and the most oxygen (gas) is also out then. Much better when making a developer from this "photo" water.

Gerald and Robert,

This would be acceptable when I find out I'm out of "chemically pure" water. But it isn't something I'd like to do very often.

fdonadio · Nov 16, 2015

Thanks everyone for all the information.

Thinking about it, my conclusion is:

1. Tap water that is safe to drink would be OK for mixing photochemistry;

2. Boiling the water would make most of the chlorine go away;

3. A good filter (or a deionizer) would be good enough, if tap water contains a considerable amount of solids (but then it wouldn't be safe to drink);

4. If one wants convenience, distilled water is cheap;

5. If one wants even more convenience and is paranoid about water purity, a reverse osmosis filter would be the solution.

M Carter · Nov 16, 2015

We have an under-sink filter for drinking water; it lasts a year or two before the rate slows down. I use that water to mix fix, stop and paper developer.

I use distilled water to mix film developer (and usually lith developer, since I keep it for months/years as old brown);

I use regular tap water for washing film and prints;

I use filtered water for final print rinse;

I use distilled water for final film rinse.

So I may go through 2-4 gallons distilled water a month - it usually sells for .50 to $1 a gallon in my neighborhood.

Reverse osmosis - I had one as an undersink filter - but I understand they use, say, 2 gallons of water to make 1/2 gallon of filtered water. So if you live in a drought area, perhaps research those?

fdonadio · Nov 16, 2015

M Carter, I knew that some distillers waste water like that, but never heard of anything about RO filters... I should research a little more.

Jim Noel · Nov 16, 2015

Simon Howers said:
I suggest a 'reverse osmosis' filter. These are available for a reasonable price at aquarium shops. A typical filter, once setup properly, will deliver water containing no more than 10ppm dissolved solids - which is fine for photographic chemistry. You can keep fish as well!

I used one of these devices when I lived in London where water quality is terrible - there is so much chlorine in the water that a bath looks green!

Good luck

Simon

I second the use of reverse osmosis. I have used one for more than 25 years and couldn't be more pleased with the water quality for photography as well as drinking and cooking.

Deionizer or regular water filter?

Privacy & Transparency

Privacy & Transparency