Mineralization and degassification are two different tanks in the UVI system. Your mineralization tank is filled with kaldnes K1 media for the bacteria to colonize and is aerated, while the degas tank comes after the mineralization tank which is also aerated - it off gases compounds that will be harmful to plants.
You may not need these if you are going from your fish tank/sump directly to your grow beds. If you have alot of fish then you probably need a settling tank to remove excess solids. Grow beds only need around 10-20 grams of fish food/day as an input to support a square meter of plants where as a DWC system is 60-120 M2 with a lot of solids removal.
I am assuming you have a sump... are you using SLO (solids lift overflow) for your fish tanks?
3 sumps, 700 gallon system. Not familiar with SLO. The system is very light on fish, less than half capacity, but bc of our goals, and the fish, I cannot add more fish at this time. That's why feeding heavy so I can fill my grobeds
I understand the purposes of the demineralization/degas tanks, wondering if I need these or can I just transfer removed solids to the main sump with pump and get them quickly into grobeds?
Maybe connect all your sumps with SLOs?