I have just set up my catfish tank with sand. I rinsed out the sand as much as I could but it's still pretty cloudy. How long does it usually take for sand to settle? Did I maybe need to rinse out the sand more?

Selena - I can't see your image, but my answer is that the sand settles almost instantly. Sand is defined as rock particles of a certain size. Sand-sized particles are fairly large and settle right away. The fines that are in with the sand (silts, etc.) can be much much smaller in size and will take much longer to settle. If the water is being agitated by aeration, filters, etc., it will take even longer. Your filter (given enough media to adsorb the fines) may do the job, or may not (if using coarse floss).

I would suggest that you rinse the sand in a container until the supernatant comes off clear.

Dennis

I agree - the sand itself is usually heavy enough to settle. The fine particulate that is left is better filtered out or removed through rinsing.

Catfish are bottom feeding fish - as are goldies. They, too, root around in the substrate on the bottom. Could it be that your fish are constantly stirring up the substrate in their search for food? Goldies will keep a sand based tank in a constant haze of sand with their actions.