Crushed Oyster shells as a sand bed?

[Rickdolbier]

I was wondering if anyone could tell me if it would be OK to use crushed oyster shells as a sand bed? The LFS here sells Sand for about $25.00 for a 30 Lb bag! I am going to need around 250 -350 Lbs and I found that I can get Crushed Oyster Shell at the local farmers feed store for around $7-8.00 for a 50 Lb Bag and the quality looks good! They sell it as a calcium suppliment for laying hens. Thanks . . .

Rick D.

[Rickdolbier]

All we have here in "good 'ol Gainesville, FL" is silicate sand (Other than the $25.00 per bag stuff). I really though that all I should use is calcium based sand? Will critters burrow in silicate based sand and doesn't it cause alge blooms?

[Shoestring Reefer]

YES, IT CAUSES Algae blooms. Do a search for SOUTH DOWN SAND. The name is different now, and it's sold at home depot for about $5 for 50 lbs. Clear bag with blue and red letters, and I think there's a kid on the bag. It's carribian play ground sand, no silicates, white, and pretty clean.

[freakyreef]

Old castle is the new name for Southdown.
As far as silicate sand causing algae blooms, I would say it depends on what kind your using. The amount of free silica in some of the sands isn't enough to cause any problems. There are MANY people using silicate based sand with no problems.(I am one of them) I am not trying to step on anyones toes here, but to say that silicate based sand WILL cause an algae bloom is overstepping, can it cause algae blooms? Yes, depending on situation. FWIW

[Rickdolbier]

Old Castle (Southdown) is not sold in Florida. How can I get it without paying outrageous delivery fees? And does anyone know about my original question -- What about crushed oyster shell?

[freakyreef]

Oh yeah, skipped right over that. You said they are sold at your local feed store. Have you checked to see that it is pure, with no minerals or anything added? I cant see anything chemically wrong with this, might check over at the chemistry forum to be sure, however detrius will be trapped in the substrate due to its large size. I have a crushed coral base about an inch thick and personally think its too thick. I stir up the bottom quite often and am digusted by the sight.

[Rickdolbier]

The only thing that I have heard is that it may have a high protein content. What size should the substrate be and what is "detrius"?

[freakyreef]

As far as depth, I dont think anyone knows for sure. IMO The shallower it is the easier it is to keep clean of detrius (fish poo) :lol: I have seen a lot of people going bare bottom tanks or with just enough to cover the glass/acrylic. Your liable to get all kinds of reccomendations. This pertains to crushed bottom, for a sand bed, 4-6" in depth.

[wasp]

I have a crushed shell sandbed, the pieces are up to around 1/3rd inch, it is 2 inches deep, and then a mesh screen, and 2 inches of fine aragonite on top. The fine aragonite is to stop detritus (waste fish food, etc) from building up in the larger crushed shell. It works excellent as a nitrate reducer, I have zero nitates. Only thing with the crushed shell you are getting, it will almost certainly contain metal contaminants from the crushing process. My own shell was collected at the beach. If you could find out how it was crushed, you may be able to make a more informed decision.

[Shoestring Reefer]

Oops, I missed the point, too.

In my freshwater days I used graves substrait, probably 4-6 mm. When I cleaned it out after a year the bottom was NASTY. any areas that couldn't be vaccumed (like under plants) was black and loaded with organics. I was going to give it away, but ended up throwing it away because it was so nasty.

If you go with something big like crushed oyster shells, I wouldn't go very deep and definately wouldn't put any rock work above it.

Oh, and really rinse it, even if it doesn't say it has chemicals added. The crushed oyster shells I used for making rock were loaded with organic stuff. It looked clean and smelled clean-untill it got wet. I bet 10-15% went down the drain, no joke. Before I rinsed it, I actually posted somewhere that it was really clean. If only I had known...

Detritus = poop, etc.

[Rickdolbier]

Thanks, you guy and this site is TOPS! I am learning so much from this site . . . MEGA CUDOS to you who run this site! :-) And thanks for all who share their knowlege! I am gratefull.

Rick D.

[RicksReefs]

since your in fla., have you tried the gainesville reef club
or BARS (www.reefers.org ) many people here in fla. use
what eventually becomes caribsea aragonite sand @
$20 a ton (yes, ton!) you can PM me for details if you'd like
or post on the BARS forum. (caribsea frowns on open
discussions ;) )