Is an cold liquor tank is necessary for an micro brewing system below 10bbl? Would you need the cold liquor tank as RO water tank for blending the chemicals?
You can get by without one. Using cold liquor through your HX during knockout means you don't have to have a two-stage HX of water/glycol. You can spread the cooling load of knockout over a longer period of chilling down your CLT between batches, meaning you can go with a smaller glycol chiller.
As Linus said, you can use a two stage water and glycol HX instead of a CLT. You don't necessarily need a bigger chiller to accommodate the HX as long as you shut off your tank jackets while you are using the HX. If your HX is sized right, you should be able to run into the unitank in less than an hour.