Does this fit the older Innovative Marine Nuvo 30 and 38 aquariums?
YES. The width and depth fit, but this basket is shorter. Simply raise the height of this Media Basket by adding legs, or having it rest on squares of egg crate. (lighting louver)
Do I need two Media Baskets, one under each intake?
That all depends on what you will be stocking in your aquarium and how much filtration media you may need to run. Generally this basket is large enough to handle all the chemical media needs of the aquarium. This is why we offer the inTank Filter Floss holder Part Number - IM40FH. Having an inTank Media Basket under one intake, and inTank Filter Floss Holder under the second intake, saves money and still protects the rear chambers from detritus.
In the Fusion Lagoon 50 you may want to run two inTank Media Baskets as the water volume is larger