High Alkalinity

[Lowboy]

Our water is nearly off the scale in alkalinity at 250+. The water is only moderately hard. Would a water softener help much?

We use an RO for drinking but a whole house RO is expensive and maintenance would also be costly.

[Akpsdvan]

Softener is going to work on hardness not the alkalinity.
High is > 300mg/L
Low is < 30mg/L
Looks to be no federal limit either way.

One way of lowering it is with feeding white vinegar, citric acid ..

[Lowboy]

Thanks for the reply Akpsdvan. Our alkalinity is off the chart on our water test kit above 300mg/L. It leaves white spotting on everything it touches like shower glass and on the car if you wash it.

Would a carbon filter help any?

The farmers use acid on the crops to combat high alkalinity but injection into a water system would seem costly. Our total hardness is in the ideal range and the pH is showing 7.5.

[Akpsdvan]

I would look to have a test on silica..

Have you also done a test on hardness either in grains or ppm?

[Lowboy]

Here's a link to a report from our water district for 2009. There is a Silica test report showing 32-39 Mg/L..

http://www.douglascountynv.gov/sites/CDAdmin/utilities/ccr/East_Valley_Water_Quality_Report.pdf

[Akpsdvan]

Do some searching on Silica.. even if the hardness is removed some of the challenges that you have will still be there.. no easy way of silica removal.

[Lowboy]

Good point on the silica..

After some internet research the white spots are evidently from the silica and not alkaline. Our under sink RO removes the silica to the point of not leaving any white scum in the bottom of a pan boiling water many times. I've purposely boiled water straight from the tap and the white scum starts forming after only one boil.

As we live in a valley with geothermal springs all around us the silica makes sense. Rather than a DI tank I think the answer is a whole house RO. I have a utility room with the incoming water service looped into it so I can separate the outside irrigation water from the house. We only use about 5000 gallons per month in the house so the RO would be practical.

[Akpsdvan]

If you use Whole House RO, what kind of plumbing is there right now in the house? Copper?
RO water gets the ph lowered... and most likely will be a challenge with the copper pipes.
Then there is the holding tank that you will need for the RO water and some thing like a Grundfos pump for getting the water from the tank to in the house lines.
For an RO of the size most likely for your place , just the RO system could run in the 5k range, then there is the tank and pump to take in to pricing and that could run another 2-3k depending on size of tank and pump used..

Just saying..
Prices may or may not be close but are some thing to think about.
There are those that go the way you are thinking.. so there is nothing wrong with it, nor am I saying not to, just keep in mind that it most likely will not be cheap, nor will it fit in a closet.

[Lowboy]

Another good call...

I never thought about the copper pipes which is the old part of our house. The new addition upstairs is Pex. It's quite ironic how the RO water gets mad and wants it's metal and minerals back.

I have plenty of room in the utility room for a RO like the Merlin on E-Bay below with pump and tank etc.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270652975266&ssPageName=STRK:MEWAX:IT#ht_7137wt_907

We've used the "snake oil" clamp on Magnets and believe it or not they do work on the white scum staining to a certain degree.

With the copper pipes in the downstairs I fear the RO would be too much for the copper.

[Akpsdvan]

One of the things about RO's that is not really talked about is water temp.. oh they say X unit will do say 200 gpd, but what is not said is that is on 77F water.
I know this because years ago I ran an RO plant with 2 3300 membranes and between the 2 that was 6600 gallons that I should have been able to do, but only was able to do 2500 and the biggest reason was that the water temp was at 35F...
So depending on the water temp that you are dealing with will be the real number of gallons that any RO unit will do for you.
The other is that any RO will work better with not only 0grain water but rather 0ppm hard water.
1 grain is 17.1ppm this was the other thing that I learned first hand that by having the softener at max salt per cubic foot I was able to get the most out of the RO, if I ran at say 6lbs per cubic then I was down on the RO and the distiller worked harder and was down for maintenance 4 times a year over the 3 times if at max salt... down time equals man hours to clean and lost production.
So a softener before to pre treat the water, ro system , storage and then maybe calcite or soda ash injection to bring the ph up , and if calcite is used and the water now again has hardness if that is to much a softener again ... but there the hardness of the water can be adjusted depending on how hard you wish it to be by adding some of the ph corrected water to the re softened water..

[pawaterguy]

What an RO membrane produces is also connected to the incoming water pressure. The higher the pressure the more GPD it will produce and at a lower TDS/higher quality. One of the other downsides to the whole house RO is that you can say good bye to cold tap water. The temp of the room where the tank is stored is the temp of the water you'll get from the cold tap. And, depending on how large of a tank you use and how much water you use, it may correct itself in PH before it comes through the system.

[Lowboy]

The other spot I'd be in trouble with is the tankless Rinnai heater and the hydronic heat exchanger for the forced air heater connected to it. All copper piping..

What about using ceramic filter media for silica?

[Akpsdvan]

Here are a few links on Silica removal..

http://www.nationaldriller.com/Articles/Feature_Article/4f751c94a9197010VgnVCM100000f932a8c0____

http://www.hv.com.my/SilicaSRC.htm

http://www.ntut.edu.tw/~wwwoaa/oaa-nwww/oaa-bt/bt-data/std/21/paper_01.pdf