How's it going bud! Yes our water has always been quite hard, it leaves rust stains everywhere. CLR gets a monthly payment from us lol. The water filter system i put in was just a cheap one i found on Amazon, I was hoping it would help but it gets clogged really quick.
The Duke project with the RBF pairing is really exciting. I also paired the Duke to the Kush Kush. I've been trying to make new crosses as it seems that's what the market is into right now, but I'm still working on the old lines to keep them progressing. I may have to debut a few of the new autos this year in the outdoor.
-- good Sunday to ya Jean!
Fe is an SoB to deal with, and to be rid of it you need first to get a test done to assess levels, then make a choice on how to remove it... Sounds like whole house is the ticket but if not, a smaller scale system is fine... RO systems can deal with it, but in higher levels it'll foul the membrane pretty quickly as you've seen -
An ion exchange resin bed is another way to go...similar to typical water softeners... other ways include some sort of oxidation treatment that basically turns it into rust as a precipitate that can be easily filtered out...
Check out some options mate, considering what the down stream costs and PITA factors it presents, some sort of filter system would be a solid investment... For sure your nutes will not play well with any dissolved forms of it, and even as a critical micronute, this liability in potential cross reactions (and consequences) is unwelcome to say the least!
Something is definitely off about my water in the spring for sure. The plants health is obviously tampered which is visible. I double checked the PH with the pen and some paper strips with color indications. Re calibrated the pen checked PH with both and its definitely over 9 currently. I will have to going forward use some PH Down to get into a better range around 6.7 for my growing style. I believe since we have been getting a lot of rain and the farmers have been pumping the fields with their fertilizers and I have a shallow natural spring fed well I may be seeing some runoff possibly. Luckily none of us drink our tap water. Not entirely sure if that's what's occurring but it has for years seemed my spring grows always have the worst issues I need to address.
-- I don't trust in coincidence!
The hitch with pH down is you're adding in even more ppm's, and most are hydroxide based, strong but kinda harsh... Weak acids (vinegar, citric) tend to wuss out, they lack "staying power"...
Alternatively, drinking water from a self fill store or machine is an good option, if not cheap. What does your family use at home to drink/cook with?
.... the inventory task is like untangling a ball of fishing line! 
At the very least the Orig. Haze crosses and a few other things can jet out your way this week...
