1.25–1.95 mm diameter grain size
At CaribSea we take aquariums seriously. Since 1972 we have supplied hundreds of public aquariums, zoos, aquaculture facilities, public and private institutions, and hundreds of thousands of dedicated aquarists with the highest quality marine and freshwater products. CaribSea has been in the forefront of the principle that substrates are a piece of equirment, not just a decorative afterthought. Caribsea substrates are as precisely engineered as any piece of advanced equipment used by today`s hobbyists and professionals. CaribSea products are the chemical support, biological filtration, and biodiversity backbone for many of the most spectacular aquatic displays ever created. We are now celebrating our 35th year in the business, and our product line has continued to grow; making CaribSea your aragonite source and so much more.
Most orders under $29 ship for only $2.99 using a mix of economy shipping methods including UPS Ground, USPS First Class, and/or SurePost. Your order will be delivered in 1-7 business days after it ships out.
We ship 99% of the products we carry for free within the contiguous United States using a mix of economy methods including USPS First Class Mail, SurePost and UPS Ground. Your order will arrive in 1-7 business days. Just spend $29 or more!
Over 90% of shoppers receive their orders within 2 business using UPS Ground. Upgrade from free economy shipping to UPS Ground for only $2.99—or spend $250 and we’ll upgrade you automatically!
Expedited shipping services are available for most products if you are in a hurry. Get guaranteed delivery in 2 business days, 1 business day, or next day by 10:30 am. Costs vary by location.
Same-day shipping is available Monday-Friday for most products—place your order by 10:30 am PST. Pre-ordered and back-ordered items do not qualify, nor do drop-shipped, live, or frozen shipments.
We ship live plants, live foods, and frozen foods within the contiguous United States. Each of these categories is subject to its own $19.99 flat-rate shipping fee to cover the special packaging and/or expedited shipping costs required to ensure safe delivery. Orders with 12+ live plants ship free!
Return any new and unused item within 60 days for a full refund. Having difficulty with a product? Contact us to speak with an aquarium expert. If you need a replacement, fill out this form.
A small segment of the 180+ brands we carry require that customers contact them directly if/when problems arise. You can view the full list of those brands and get their contact info here.
Marine Depot is an authorized reseller for every product we carry. That means when you buy aquarium supplies from us, your products are not only backed by our own 60-day return policy, they also carry full factory warranties, where applicable. Some items have a 1-year warranty, others have limited lifetime warranties. Warranty coverage varies from manufacturer to manufacturer, so please read the product description of the item(s) you are considering thoroughly for details or contact us if you have warranty questions.
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You can also get bonus reward points by purchasing select items during special sales and promotions.