I've had good luck with the disposable water filters by Camco too when rinsing. I had an old one laying around I tried once and it worked well in reducing them. Also avoid direct sun. I always wash in the early AM before the sun gets the unit or vehicle hot.
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2014 375 BHFS Eagle Premier
2014 Ram 3500 Longhorn DRW CC
6.7 CTD, Aisin, 4.10's
Yamaha EF3000iSEB
I use my home built DI system made from components purchased from www.bulkreefsupply.com .
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Ed and Sheila
Hartselle, AL.
2016 Seneca 37 FS
2016 Jeep Wrangler Unlimited
2019 Silverado High Country 4x4 Crew Cab
Australian Cattle dogs Zan & Tre
I bring a bucket of softened water from the house and do a final rinse with the softened water and then use wax as U dry product. Have to make a few trips but no hose attachments so no other way to get soft water to the RV.
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2017 SLX 195RB
2021 Jeep Grand Cherokee Summit L 5.7L V8
Andersen WDH hitch, Renogy 100 AH Lithium &
200 Watts solar panels from Renogy
Prev. '14 Jeep Grand Cherokee Overland, gas 3.6 V6
I just do mine in sections and dry each as I finish it (avoiding direct sunlight). I have a couple of large bath towels and a shop broom...I wrap the towels on the broom head and dry each side in less than 10 minutes.....no spots. Then wax afterwards. We have pretty hard water where I live too. Soft water is the only way to eliminate the minerals (various systems as noted above) but if you dry the unit before the water drys leaving the minerals it works too...just takes more effort, but I need the exercise. YMMV>
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2016 Jayco GreyHawk 31DS
2016 Jeep Cherokee Trailhawk Toad.
SE Washington State