I am in the early stages of a water quality project. We have a mountain house that we have been working on for a few years but still not quite able to stay up there yet. The symptoms we have are reddish water out of the taps and a lot scale built up and iron staining on brand new toilets that have been lightly used in the last year. I had a water test done to see if it was safe, I didn't know what all to test for so I picked arsenic, coliform, and iron(I could see the staining already). Other subjective data: no sulfur smell, no slime in the toilet tank.

The results:
coliform negative
Iron 1.04 mg/L
Arsenic .053 mg/L

I know I don't have enough info to move forward so my first question is what do I need for water tests? There is a company called Aquaknow that will test for this list for $100.

Chemicals Metals
Aluminum 0.1
Arsenic 0.005
Barium 0.30
Cadmium 0.002
Calcium 2.0
Chromium 0.010
Copper 0.004
Iron 0.020
Lead 0.002
Magnesium 0.10
Manganese 0.004
Mercury 0.001
Nickel 0.02
Selenium 0.020
Silver 0.002
Sodium 1
Zinc 0.004
Inorganic Chemicals and Physical Factors
Alkalinity (Total as CaCO3) 20
Chloride 5.0
Fluoride 0.5
Nitrate as N 0.5
Nitrite as N 0.5
Sulfate 5.0
Hardness 10
pH (Standard Units)
Total Dissolved Solids 20
Turbidity (Turbidity Units) 0.

Any recommendations on what to test and who to test it would be appreciated. Do I need to know dissolved oxygen?

The iron topic is a little confusing also. It seems there are three types:
ferrous iron- clear water iron, water starts out clear and then turns red after it has a chance to oxidize
ferric iron- comes out of the tap red but the rust particles settle in time
colloidal iron- oxidized iron where the particle size is very small and it is bound to an organic. Will never settle to the bottom.

Is there a lab test to distinguish what I have? the toilet water always has a tint(seems more yellow than red) so I was thinking maybe I have the colloidal version. I would love some suggestions on how to distinguish.

The arsenic is a whole different animal. I found one link that implied you could reduce arsenic with a iron filter and an ion exchange system(regular water softener?) Here is the link
. The thought being if have an oxidizing media then some of the arsenic will bind to the iron and can then be filtered out. In the ion exchange system apparently one type of arsenic(As V) will bind to the exchange media. It competes with sulfates so your water needs to be low in sulfate content. Is there a way to know what type of arsenic you have?

I have already asked a ton of questions so I will stop here.... First thing is to get the right testing done.