Sand particle size for DSB

[MarkD40]

I am in the process of setting up a 20 gallon tank next to my 75 gallon sump to function as a refugium. I have heard repeatedly that the size of the sand grains is important. What size is the best. Should it be arragonite sand? Is it possible to have too fine a sand or will it pack too tightly?

The water from my display tank enters a perforated basket filled with filter floss suspended in a 5 gallon bucket. The bucket has a bulkhead in the bottom and the water is then pumped through a berlin venturi skimmer before the water enters the sump. The water from the sump is then pumped through a 25 watt UV sterilizer on it's way back to the tank. Am I using too much mechanical filtration for an adequate amount of detritis and organic material to get into the sump to support the needs of sand stirrers? Will enough "food" enter the refugium to support little things?

Thanks!

 

[Pandora]

Mark:
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I prefer around 2mm grains, I think I read this from Dr. Ron's articles previously also; there can be some variation. Aragonite is the best (this means the composition is calcium carbonate and generally you can infer that the grains are small, not like crushed coral). You might also hear of it described as oolite, this just talks about the grain shape ("egg shaped", round).

My opinion on yuor sump setup is that it should be fine to get the nutrients down into the area where you are housing your refugium dentrivores (I take it the purpose of the perforated basket is as a "prefilter" for bigger stuff not to drop in, and not too fine a mesh?). On the UV, you'll hear lots of varying opinions on this, but honestly, a 25 W on the rate that your pump must be set at is not going to do all that much as far as disease control anyway (higher wattage to be really effective, but then at that rate, you'll end up killing some of the bugs you want to circulate back into the main tank, catch 22). I scrapped mine years ago. You're a doc too, good preventative measures are key; can prevent a lot of problems before they occur with QT & good water quality management.

 

[MarkD40]

Actually my UV is 40 watts. Been a loooong day. Thanks for the feedback Pandora.

I would rather have a bottle in front of me than a frontal lobotomy. (Old one but still good)

 

[lbear]

<a href=showthread.php?s=&postid=6741399#post6741399 target=_blank>Originally posted</a> by Pandora
Mark:
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I prefer around 2mm grains, I think I read this from Dr. Ron's articles previously also; there can be some variation.

Based on Dr. Ron's article, sediment particle diameters should range from coarse sand (2.0mm) to fine sand (0.063mm). The sediments should be skewed so that about 60% of the sediment is between 0.5mm and 0.062mm diameter.

I am new to the SW. I am also interested about setting up DSB. I also read the article inland aquatics. http://www.inlandaquatics.com/info/faq_lsand.html just wondering how many people follow those steps and how many people have success.

 

[Pandora]

Yup, that's true lbear (been a while since I read that article)... but I think in practice, no one is really going to be measuring their grains down to the micron. It's a good idea to get the majority of your grain sizes around this size with a variety, and not too big and jagged so that the dentrivores feel comfortable in it... I think that's the important thing. My sand is a mix of mostly Southdown, with a small percentage of silica sand (Quikcrete) to increase volume, and also oolite sand from other sources.