What Corso312 said,
black with yellow lid at Home Depot. Very sturdy won't flex from water like Rubbermaid.
It was even recommended by My local Hydro shop as the best DIY container for a reservoir.
I still prefer a Bucket and lid, 3.5" net pots fit nicely, 4 cut in a cover.
I like the versatility and flexibility of smaller individual DWC systems in buckets.
works great for 1 - 4 net cups you can't fit more than 4.
3 1/2" net cups with 4 buckets w 4 holes each that's 16 plant sites and only 4
containers to clean every two weeks.
4 buckets fit in Less than 3' square space so 400 watts is fine in my space which is Tiny.
It's easy to just take a clean bucket and cover and move plants so the water/nutes can be changed.
I do use one large air pump and multiple large air stones 1 for each bucket.
At proper level water splashes the net pots nicely, you do have to maintain your water level and watch your ppm and PH
but it's not rocket science and I am no genius, just a Buzzed Noobie who smoked a Doobie or two....

peace,
DZ