I think its just the sediment from the sand and it needs to settle... i only had like 5 gal. in it. so I took a cup and got the water out and brung the tank to the tub and put the sand into a buck et and washed again... looks a tad cleaner... but we'll see. I'm about to try again.
havn't quite decided on what to put in iot yet... I'm interested in eels.... but nothing for sure!!!