OT- Reverse Osmosis water system??

Re: OT- Reverse Osmosis water system??

Kneale Brownson

The house we just move into came with an RO drinking water system installed under the kitchen sink with a separate faucet above. When I called the supplier about getting replacement filters (there are three plus a reservoir tank in place), they indicated the installation was on a maintenance schedule and a technician would be visiting next winter. Apparently, water system testing determines how long filters should last, and is an important part of determining what you need.

I have years of experience doing plumbing work in the dozen rentals we used to have, and the RO installation I see under the sink looks pretty straight forward. I would have no problem punching a hole in a metal sink and installing the single-lever faucet or tapping into the water supply line. If you'd feel comfortable doing those things, the installation would be a DIY possibility. But the water testing, as I understand it, is a bit more of a challenge.

The system seems to work great, by the way.

Question

Bill Tindall, E.Tn.

I know the science behind how they work. They exclude dissolved ions and molecules from the water that passes the membrane. May seem like a dumb question to someone that uses one, but why put one on drinking water? What undesirable stuff is being removed?

Re: OT- simple test for hardness (lime)

Larry Clinton At Frankfort, (Central) Indiana

Many years (about 60) I trained at Calgon corporation on the servicing / sales / testing of Water treatment systems.

Most water softeners are sold basically to remove lime and iron from drinkable water. RO systems do remove more contaminates than the conventional "water softeners".

However to determine if a softener is removing the lime "hardness" from the water there is a very simple test.

Fill a glass about 1/2 to 3/4 full, and add 1 or 2 drops of Ivory dish SOAP and shake it (with your hand over the top).

If the water softener has removed the lime there will be quite a bit of suds on the top of the water in the glass and the water below the suds will remain clear. If the water is "hard" (contains lime) there will be little or no suds and the water will become cloudy!

Note this will not work with dish detergent, only with pure SOAP.

Re: Question

Paul Leuba

Our well water at home is quite acidic. We installed an acid neutralizer and water softener to prevent the pipe and fixture corrosion that had been occurring up to that point.

The softener has been a great help in preventing soap scum buildup on showers, tubs and dishes. It also provides for the use of much less soap and detergent in the laundry, dishwasher and shower to achieve cleanliness. That a benefit to our septic system.

We installed an RO system for drinking water and ice cubes to remove the residual salts introduced by the neutralizer and softener. The drinking and cooking water, and ice cubes really have a much better taste compared to water not processed through the RO system.

Paul in Hunt Valley, MD

Re: Question

Larry Clinton At Frankfort, (Central) Indiana

Bill I am not real well educated on the RO systems but they do remove all tastes, color (usually from tannic acid) and minerals that the conventional Ion exchange systems do not remove.

As i am sure your aware, the conventional softeners only (aside from some particle filtration) exchange the iron and calcium

ions with sodium ions.

Basically the RO water is more like distilled water.

more questions

Bill Tindall, E.Tn.

(I have a general interest in water chemistry)

An RO unit to remove sodium chloride either from water softening or salt water infiltration makes perfect sense. Backing upstream I am puzzled. I don't know how water can be acidic and "hard" from calcium and magnesium salts at the same time, unless treatment for acidity leads to the water being "hard". If you have any more information on your situation I am curious to learn about it.

Re: OT- simple test for hardness (lime)

Tom Norton

The reason for considering the RO system is my wife has developed a few allergies and it appears that the water after it is softened may be a problem. We are try to isolate the problem by her using only bottled water for a while.

Re: more questions

Paul Leuba

The acidic water from the well is first put through an acid neutralizer tank that contains calcite crystals (calcium chloride crystals I believe). This process rises the ph of the water to near neutral, however the addition of the calcite to the water raises the hardness to the point where much soap/detergent is needed to raise suds, and a film of soap scum starts appearing on dishes and plumbing fixtures, particularly tubs and shower enclosures.

The solution to this problem is to then pass the water through a softener system where resin media binds to the excess minerals thereby reducing the hardness of the water.

Both the neutralizer and softener tanks require back flushing, perhaps weekly, perhaps more often if the hardness is high or water consumption is high. The softener is back flushed with a salty brine (sodium chloride) to regenerate the resin media. This process unbinds the minerals from the resin and flushes it to an external sump of some sort. There is some sodium chloride residue that remains in the system that an RO system is effective in removing if one is installed downstream from the softener.

So, in summary, there are three separate treatment systems in our configuration. They are connected in serial with the neutralizer first, the softener second, and the RO system third. The RO system is used to process only drinking and cooking water, and water used to make ice. The warranty of some automatic ice makers is voided if softened water is plumbed to it that is not first treated with an RO system.

Paul in Hunt Valley, MD

Re: Question

Jesse Cloud

Many of us out west live in areas with a history of volcanic activity or downstream from such an area. Such areas have naturally occurring arsenic, often way above the EPA standard. RO's will remove enough arsenic to be within the standard.

As to the water testing, I don't think those parameters change often, unless you have some potentially harmful industrial or military (huge offenders) activity nearby. I would simply continue to use the filters and membrane currently installed.

I have never done the maintenance myself (too arthritic to bend under the sink and twist around), but I have watched the plumber. It takes him about 10 minutes to swap out the filters and the membrane. Looks very straightforward. No special tools. Ours is a kinetico.

I have mixed feelings about using the RO for drinking water. It filters out most minerals and your body does need trace amounts that you will need to get somewhere else.

Re: Question

Kneale Brownson

My location in Utah is one such downstream-from-volcanic-activity mountain creation. Our town-processed water is "safe" to drink but not really tasty or healthful.

Micro plastic is the new polutant

Chemistry of what is going on

Bill Tindall, E.Tn.

I would like to know what is making your water acidic. That is rare unless it contains sulfur. Sulfur will oxidize in oxygenated water to make sulfuric acid.

Your incoming water is exposed to calcium carbonate, limestone, which is a base. The calcium carbonate may be just ground up pure limestone, or a manufactured equivalent, maybe with high surface area to get a fast reaction. How much does it use a month?

The acid plus the base makes neutral and as you say the product is calcium bicarbonate, hard water. Your water must be very acidic to dissolve an appreciable amount of the calcium carbonate. Interesting....I wonder what the source of the acidity is.

Re: OT- simple test for hardness (lime)

Walta

To me what the RO filter removes is irrelevant, the fact that the water tastes better makes the RO system worthwhile.

If the water preshure falls below 60 PSI, as most well water systems do you should get a RO system with its own pump.

I have found this system from Oceanic Water Systems has been inexpensive and reliable.

I chose the 4 stage system with the pump $180 shipped

http://oceanicwater.com/index.php/4-stage-reverse-osmosis-drinking-water-filter-system-permeate-pump-100-gpd.html

Re: Chemistry of what is going on

Paul Leuba

Well water in this area is naturally acidic with a ph of around 5.8+-. There is no hint of a sulfur oder from the water. I don’t believe acidic water is uncommon because of the number of neutralizer systems that are sold. Do you happen to know the ph of the water in your area?

The consumption of calcite crystals is about 3 - 3 1/2 lbs./mo.

Paul in Hunt Valley, MD

Re: OT- simple test for hardness (lime)

Tom Norton

Interesting $. Two of our friends have Kinetico units and they paid $1500+!

Re: Chemistry of what is going on~ not unusual!

Larry Clinton At Frankfort, (Central) Indiana

As I stated before many years ago I sold and serviced Water conditioning systems.

I live in Indiana and at the time was in the Northern part of the state. I had several issues with acidic water. When I consulted with the Calgon Corp. lab and sent them samples, they concluded the acidity was caused by tannic acid.

The wells were drilled into a layer that a glacier had plowed under that contained a forest and that the decaying vegetation had contaminated the water with the tannic acid!

In one case the acidity was so bad that the well pipe was eroded away about every 5 years, we treated the home water supply but at the time nothing could be done about the well itself - today possibly a plastic insert could be used, don't know.

In another case the water was not only acidic but was quite brown. The water was safe to use but stained clothing etc. This was solved by use of a commercial water softener.

This area is right south of Lake Michigan, apparently the glacier stopped and melted in this area. The soil in the small town I lived in was yellow sand like the Indiana Dunes.

Currently I live about 50 mile north of Indianapolis. One of my coworkers had to drill a new well several years ago. At about 85' the driller struck wood, he brought a core sample into work for us to see. Pretty interesting as the piece looked like it just came from a living tree, showing no sign of aging or decay!

Re: Chemistry of what is going on~ not unusual!

John in NM

Pretty amazing finding preserved wood in soil at 85'. Maybe it will be petrified wood one day?

I would suppose that there is a lot of organic matter soaking up any available oxygen in that groundwater, that is commonly seen drilling holes for mineral exploration - hit ground water and the rock changes - drastically if there are many ore minerals, more subtly if its just the usual iron bearing minerals found in igneous and metamorphic rocks. Oxides above, sulfides below. One place I remember in Mexico it was within about 12' of the ground surface!

We did occasionally bring up a piece of wood, but those were old mine timbers!

Even  more interesting chemistry

Bill Tindall, E.Tn.

It will take about 1/1000 of the calcite (calcium carbonate) you are using to move the pH from high 5's to mid 6's where what ever the problem is at high 5's won't be any longer. The rest of the calcite is just dissolving to make your water hard.

Distilled water equilibrated with air containing its normal concentration of CO2 has a pH about what your water is. The CO2 dissolves in the water and makes a tiny amount of carbonic acid.

If your water source is in rock that doesn't dissolve much, granite for example, it will not be buffered. Exposed to air the water will acidify to a pH in the high 5's by dissolving CO2. This situation could be what you have, or you might have some other source of acidity.

Suppose your water is simply pure water saturated with carbon dioxide. If you pass this water over calcite, exposed to air, given enough time the calcite will dissolve until it is saturated with dissolved calcite, whose solubility is about 0.01% calcium, quite hard water. Water coming from a limestone source will be about 0.01% calcium. If you are dissolving 3 pounds of calcite and you use 3,000 gallon of water the resulting water will be about 0.005% calcium. moderately hard. The residence time of the water in the calcite bed will not likely be long enough to completely saturate it with calcite.

Now you "soften" this water and it will have the calcium replaced by an equivalent amount of sodium. Then you reverse "osmoss" this water to get mineral-free water. If, or when, this water is exposed to air you wind up with pure water at pH in the high 5's, just where you started.

To test if the water pH is simply the result of dissolved carbon dioxide boil it (which will strip out the CO2) and test again. I don't know what problem CO2 saturated pure water might cause, but I would want to know before I spent all the expense to make it hard and then turn it back into what I stated with.

Re: Even  more interesting chemistry

Don Stephan

Certainly one would hope a complete study is made by the companies offering water treatment systems and carefully explained to potential customers. But what is not clear in your explanation is how treated water would be exposed to air long enough to absorb carbon dioxide and lower the pH. Isn't the water in a closed system prevented from contact with air, until it leaves the water tap? So many refrigerators today have water dispensers in the door, it would less likely people would have open jugs in the fridge, where carbon dioxide could be absorbed, unless they use one of the countertop filtering systems. If the latter, how quickly would the pH of water lower from carbon dioxide absorption?

Re: Even  more interesting chemistry

Paul Leuba

The entire reason to use a system to neutralize the water, and then to reduce the subsequent hardness, is to prevent corrosion of the copper pipes and water fixtures through out the system. The system is of course sealed from the atmosphere and not picking up CO2 from air. What happens when we open the tap to extract water is of very short duration and does not provide sufficient time for the water to absorb CO2 from the air. There is no evidence that the water we are getting from the tap, RO or otherwise, has a PH back where we started.

The cost of purchasing and maintaining a treatment system is much less then the cost of continuously repairing pin hole leaks in pipe, repairing water damage from the leaks, and replacing corroded plumbing fixtures through out the house. We've had our neutralizer system since 1985. We've witnessed unfortunate neighbors who have not neutralized their water experience multiple bouts of the above, sometimes with catastrophic water leaks while they were away at work. Besides, the water taste is the best I've had anywhere. We are often complemented on it by visitors.

Paul in Hunt Valley, MD

What unit?

Tom Norton

If you installed one which unit did you use?

Puzzling math...

Tim Greif - West of Chicago

" If you are dissolving 3 pounds of calcite and you use 3,000 gallon of water the resulting water will be about 0.005% calcium."

Enlighten me Bill. 3 pounds in 25,020 pounds of water looks like 0.0119 % by weight, more than double your 0.005% figure. Not picking nits, just trying to figure what I'm missing?

math is fine, chemistry is not

Bill Tindall, E.Tn.

atomic wt. of calcium is 40, carbonate is 60. Calcium carbonate is 100. For every pound of calcium carbonate dissolved there will be 0.4 pounds of calcium in solution and 0.6 pounds carbonate.

Then things get more complicated. In "round numbers" every 0.6 pound of carbon dioxide in the water will dissolve 1 pound of calcium carbonate. Simplifying, we now have 2 x 0.6 pounds of carbonate in solution (actually present as a mix of carbon dioxide, carbonic acid and bicarbonate. Going through the water softener doesn't change this situation. Now we get to the RO membrane.

I'll bet it is permeable to CO2. How much winds up in the RO water could be measured by a pH measurement, but I can't calculate it. There is no way for the home owner to know. You can't taste a difference. Measuring pH reliably in the range of high 5's to low 8's is extraordinarily difficult in otherwise pure water. A whiff of CO2 containing air can change the sample half a pH unit.

Bottom line, it is possible that the system described turns slightly acidic otherwise pure water into slightly acidic otherwise pure water. Or not. Just tossing out possibilities that are chemically reasonable. Don't count on your Culligan Man to dissuade you from buying stuff that may not do anything useful.

BTW, we can thank the EPA for some of the pin hole corrosion that appeared in copper pipes. Some decades ago they mandated reduction of lead in pipe. The result was that in some water situations- unchlorinated sulfate containing water- a bacteria grew in the pipes that made pin holes under the colonies. Had a good friend that worked on the biochem of the situation. Tiny amounts of lead in the pipe prevented colonization.

The best pipe protection is water containing some dissolved calcium carbonate. It only gets worse after softening and RO, but maybe not enough worse to be a problem,...or not. Water chemistry is complicated. Corrosion is even more complicated. Put the two together and ....

Re: What unit?

Walta

Tom if your “what unit” question is to me I thought my link took you to the 100 gallon per day 4 stage unit with pump.

Given your water source you may want the 6 stage unit.

6 Stage Alkaline Reverse Osmosis Drinking Water Filtration System 100 GPD | Permeate Pump, RO pH Alkaline Mineral Filter, Tank

http://oceanicwater.com/index.php/6-stage-alkaline-reverse-osmosis-drinking-water-filtration-system-100-gpd-permeate-pump-ro-ph-alkaline-mineral-filter-tank.html

Over the last 20 year I have had 3 RO systems. The first 2 used property filters that were expensive to replace. One manufacture went away and the filter became more expensive than a new unit. The other I discovered needed a new tank when I was getting the house ready to sell so the unit was removed from service.

Walta