mixing sand

[jacksonpt]

I've got about 160lbs of southdown sand in my 75g tank that is waiting to be stocked. I've got a perc and a 6-line in there for now to keep it cycled, but I'm getting ready to start stocking it for real (i.e. more aggressive fish). I've noticed that the SD is very, very fine, and stirs up easily. I was thinking about adding 40-60lbs LS (coarser than the SD) over the top of the SD. I would hope that the LS would remain as the top layer, and be less likely to get stirred up and cause dust storms in my tank. Would it work, or would the LS eventually filter down and I'd be back where I started?

 

[bang guy]

Most likely the larger particles will stay on top.

 

[pa reef pig]

If you put a more coarse layer of sand on top if the SD, you should be ok. Smaller grains of sand tend to settle to the bottom over time anyway. Go for it.

 

[saltyrich]

Yes. Go for it. I have about 30 lbs of ls that is a little more coarse on top of 40 lbs of very fine Caribsea aragonite. It has stayed put.

 

[ed r]

If you chose the Southdown to make a DSB, you probably did so because others told you it had the small grain size needed. Putting coarse grain sand in reduces the efficiency of the bed. As others said, the large grains stay on top, but that is the worst place for them. The larger grains accummulate detrius and are not easy for the desired infauna to manuever through. The fine sand eventually settles down unless your fish dig it up. I see you have a six-line. They are hard on DSBs. They eat the critters and do dig up the bed. Without those types of fish, the bacteria and worm population create a network that holds even the very fine sand in place. Sand storms should only occur if a powerhead falls off or a fish digs. Good luck with whatever you decide.

 

[jonthefb]

I have a fine layer of sand at the bottom of my tank that gradually increases in size towards the top, and i find that it works very well. You can clearly see the anaerobic bacteria bubbles in the lower sand, while the top inch is populated with tons of worms, shrimp, and mini-stars. I think these little mini-stars actually do better in a not-so-fine sand bed, as it is easier for them to move about!
Your sandbed is going to do its job either way, and i think you will be fine. Good luck!
jon