i just switched my 46g from big gravel to flourite, about 3 weeks ago, and i thought it would only take 2-3 hours..... it took almost 6 hours, non-stop.
It took me a while to grab all my plants and put them in a bucket, and kept my biowheels under all the plants so they wouldn't dry out and die.
catching my fish wasn't to hard, and i put them in a seprate bucket with a heater. and then i cleaned the glass on my window very well since i had the chance.
i had my dad in the bathtub rinsing 2 bags of gravel all together, while i would grab small portions from the bathtub and use the speghetti strainer.
it worked well, but my back and legs were killing me
i honeslty think you can rinse flourite forever and still get it somewhat cloudy, so once it just slight started to clear up, I would throw it in the tank. i added 15 pounds of vey small gravel ( a bit larger than sand) as a top layer.
yes it is true the flourite will surface to the top of the gravel after planting, but it still looks great I think.
It will be a very time consuming process iof you alreayd have gravel like how i did, but I am extremely happy with the results.
good luck