Another question for the SIGforum brain trust:

I have my own well. I've lived here for 6 years, well system is 17 years old. Never a problem until today. I used to have Culligan change my filters once a year. They used 5 micron filters. I've been changing the filters for the past 2 years with 1 micron filters every 4 months. Today when I changed my filter, this is what it looked like:



I've got a LOT of rust in my system this time out. Normally the filters are still white with scatter sediment/sand particles. The water from the well at the well head is clear, with no hint of rust. The system runs as such:
Well to pressure tank.
Pressure tank to filter housing.
Filter housing to water softener.
Water softener to media housing(filled with Poly Guard to reduce scale in pipes https://proproducts.com/product/poly-guard-crystals/ )
Media housing to house.

Here's what the setup looks like, filter on the right, softener in the middle, media housing on the right:



Last year the inlet union for the media housing was rusted, and I had it replaced:



Now the filter housing inlet is rusted. Could I be getting rust from the housing into the pipe, and thus onto the filter?



Or could I be getting rust from the pressure tank into the filter?



Or might I have a problem somewhere else? I replaced the filter with another 1 micron filter, and plan to check it again in 1 month(vs. the normal 4 months). Could the corrosion be due to Galvanic corrosion(dissimilar metals)?

UPDATE: 19 August
I checked with the local well shop. He suggested I check for clear water iron. So I drew some water direct from the well head into a bottle, and let it sit. After 10 days there was no rust formation-good.
Had plumber come out last week. He replaced the corroded fitting. This was the source of the rust:




Plumber replaced with PEX:



I replaced the filter again since the water was turned off, and will check in another month.

This message has been edited. Last edited by: Sgt Neutron,

Definitely change that fitting to brass or copper.

I'm on the Board of our small community water system. A few years ago we had a leak. It was in the service line between the curb stop and meter. Dug it up and found someone used a black iron pipe nipple for a 4" section, right next to curb stop. Not sure how many years it was like that, but it developed a hole. You'd be amazed how much water can come out of a 3/8" hole 24 X 7. Sorry for the drift.

Could the corrosion be due to Galvanic corrosion(dissimilar metals)?

Nailed it

Are you using dielectric fittings? If all of your fittings aren't the same material, I believe it's typically required by code.

The fitting should be brass/copper.

Change it out.

Isn't there a bladder in those tanks? If so, I wouldn't think that was the source of your rust.

While I was away on business, my pressure tank crapped out. My dad installed a sofener & a USED pressure tank & my filter looked like that when I came back. Changed the tank & it cleared up.
If you had something where it was exposed to air recently, id suspect that, but it doesn't make sense for it to just happen

It was the fitting. Update in Original Post ^^^