u/Helphelpmepleaspleas

I opened an RO membrane that had been used for only about 3 months.
The end of the membrane has a lot of brown/dark specks and discoloration, especially around the outer edge. However, after unrolling it, the membrane sheets inside look relatively clean.
I included another photo I found of an RO membrane that someone said had been used for about 7 years. Surprisingly, that membrane looks much cleaner on the end surface than mine.
I understand that different source water and usage conditions can make membranes look different, so I’m not saying the comparison proves anything.
My questions are:
Is this amount of buildup normal after only 3 months?
What could the brown/black deposits be — sediment, iron/manganese, organic matter, biofilm, carbon fines, or something else?
Why would the exposed end look dirty while the membrane sheets inside still look relatively clean?
Would you recommend having the deposits or the source water professionally tested?
I’d especially appreciate input from anyone who works with RO systems or has opened used RO membranes before.

I have been searching for answers for over six months, and I would sincerely appreciate any guidance.
My two children and I all drank water from the same countertop reverse osmosis (RO) water purifier for approximately three months.
During that time, all of us developed gastrointestinal symptoms. We stopped using the purifier after we became concerned about the water quality because our home test strips repeatedly suggested elevated nitrate/nitrite levels, although we do not have certified laboratory confirmation.
After stopping the purifier, the gastrointestinal symptoms gradually improved. However, I continue to experience progressive symptoms that have not been explained despite multiple medical evaluations.
My current symptoms include:
Progressive thinning of my arms and legs (loss of muscle mass that I perceive)
Muscle pain in my thighs
Tingling or crawling sensations around my knees and in my arms and legs
Bone pain
Fatigue
Noticeable changes in my body over the past six months
I am also deeply worried because I feel that my two children may be developing similar changes after sharing the same water source.
I understand that no one can determine the exact cause over the internet, and I am not asking anyone to conclude that the water purifier caused our symptoms.
My questions are:
If you were a Medical Toxicologist, how would you approach a case like this?
Would this history justify referral to Medical Toxicology or Occupational & Environmental Medicine?
What categories of environmental or chemical exposures would you consider?
Are there any objective laboratory tests or evaluations that might help distinguish possible toxic exposure from other medical conditions?
I am simply trying to understand what the most appropriate next step would be because we have been searching for answers for months and still do not know where to turn.
Thank you very much for taking the time to read this.

RO membrane used for only 3 months — is this amount of dark/brown buildup normal?

Question about environmental exposure evaluation from a toxicology perspective