DIY people - where can i get some grommets? getting frustrated

ok im trying to build my own setup but i have run into a problem - grommets. where in the hell can i find some? i swear i looked everywhere in lowes and home depot and couldnt find shit. i ask the employees and they just send me in circles. can anyone here help me out and tell me where i need to be looking? ive looked by the plumbing, by the screws and fasteners that are in the pullout drawers, pretty much all around the stores, no luck. i just cant believe the things would be so hard to find. im sure some of you will think this is hilarious but i seriously cannot find the damn things. i have a hydro store where i get all my nutes and stuff, would they have em?

Amazon.com: 180-Piece Rubber Grommet Shop Assortment: Home Improvement

Radio snatch, or your local electronics parts supplier.

I used the ones for the toilet float to bowl, they are 3/4" and I used 3/4 pvc that was threaded. I used these on the buckets. What size do you need? There are also 5/8 hose gromets too.

High Tech Garden Supply

they pop right in if you drill the right size hole

problem is they're only 1/2 inch so drainage can choke easily if your intake is too much