I started this 20 gallon long tank about a month ago as an upgrade to my 10 gallon tank. New apartment, new city, new school, new degree - time for a bigger tank.
Some of the details:
Tank size: 20 gallon long
Substrate: 2 bags of Flourite
Hardscape: Some local rocks
Filter: Aquaclear 30
Lighting: Coralife 2x18W 30" fixture (initially)
I dumped one bag of flourite into a 5g bucket and started trying to rinse it in my bathtub. Thick, muddy brown water came out in unending quantities, making a horrible mess in my tub. It was a huge PITA and I felt like I was wasting tons of water, not to mention worries about clogging the drain with sandy particles. If I stopped stirring the flourite, I could get the water to run almost clear, but as soon as I mixed it up a little, it'd be back to mud color.
Eventually, I gave up on rinsing my flourite and let it settle in the bucket (still wet). I added a completely unrinsed bag to the tank first, then the "rinsed" stuff. I tried to avoid adding the dirty water from the bucket and the fine particles that made their way to the bottom as I stirred.
I added a little water to the tank (slowly), and it clouded up but settled within a day (no filter was running). I added some rocks for hardscape...
... and a small java fern plantlet, just for kicks. It wasn't tied down to anything, but it'd just been floating around my 10g anyway.