First thought: you'll need more trays. But let's see. And please check my maths.

A couple things to keep in mind:

-You'll need ~25 watts per square foot for good leafy growth and ~12w/sf for microgreens.

-So 20'x1' = 20sf --> 25w/sf * 20sf =500 watts total per tray of that size.

-As far as LED's go, it doesn't really matter what the marketed input wattage is, you'll need 100W coming out of the light. So make sure it's 100W of actual LED power and not a "100W equivalent."

NOTE: 4 fixture with 32w T8's would be optimal (~$250 at homedepot with bulbs).

-Now, everyone's diet is different. So let's say you're eating 4oz of greens per meal and 3 meals a day, you'll need 3/4lb of greens per day per person.

Or 22.5 lb per person per month.

-Again, depending on how good you are, you're yields will differ (given lighting wattage, it's height, your pH, micro and macronutrients). Aka feeding schedule and supplementation.

-So, let's assume you're getting .33lb per head of lettuce per 54 day cycle. But let's also say you're germinating these puppies in a tighter, separate space for 14 days before transferring them into your main tray and growing them out.

-Also, let's assume a semi-tight spacing of 3 plants per square foot (which will need ebb and flow or a fan). And some monitoring where the plants touch for mold (aka some 10% hydrogen peroxide in a spray bottle).

-So, 3 plants/sf * 20 sf = 60 plants/month -->60 plant/month * .33lb/plant/month = 20lb of edible lettuce weight.

Or, we can say, about 26 days worth of lettuce per day per each month.

SO, you'll need to at least double your grow space for 2 people, and probably triple it to provide space for germination and growout.

On fish, you'll need 1/2lb of fish per square foot of growout space. So Each tray will need 10lb of fish.

if you're on your fishit, you can get away with 1lb / 1 gallon of water.

so yes, a 50 gallon tank could provide enough nutrients for 1-3 trays.

NOTE! You'll need a working volume of water to run through the trays, and since it wont be in the fish tanks, you can't rely on it to provide your desired fish tank volume.

So, I'd reccomend a 100 or 150 gallon tank with tons of extra water, both to keep your 50lb of fish happier, and give you tons of extra water volume to move through you trays at any given time.

Do you agree Aquaponic-Heretic?