Rock and sand are partially used for aesthetics to create a far more realistic semblance of a natural reef. Moreover, substrates are the most important filter in the tank because beneficial bacteria populate the surfaces and crevices of both the rock and sand.


These bacteria then breakdown uneaten food and fish waste, filtering the tank for you. This is exactly why its called “live sand” and “live rock” because of the beneficial bacteria that live on the surfaces and populate the crevices.


Ryan aquascaping a 40 breeder


Live Rock

In the case of rock, some options are more alive than others before going into your tank. Wet rock from a local fish store that is housed in holding tanks contains the most living bacteria. Damp rock such as Real Reef is semi-live with dormant bacteria. Lastly, you have dry rock which is essentially clean calcium carbonate based rock, free of anything living.


Types of live rock


Each of these choices has its pros and cons. For first-timers, the number one goal is the easiest path to a successful and sharp looking tank followed closely by affordability.


The fastest and easiest route to natural-looking live rock is probably pre-cured wet rock from the local fish store but this is also the most expensive. At the rate of $8 - $10 per pound or more, it adds up quick considering you need 1 - 1.25 lbs per gallon and it also comes with the risk of introducing algae, pests and parasites.


Reef Saver Rock


On the flip side, dry rock such as our Marco Rocks Reef Saver comes in at ⅓ the price, around $3 per pound and is free of pests. This is exactly why dry rock is more than likely the most common rock used to build new reef tanks. It does, however, take a bit more patience upfront to completely cycle the tank, establish a functioning bacterial foundation and get that iconic purple reef rock look.


Patience is a virtue severely lacking in a majority of new reefers, it’s just time we own that.


Unboxing Real Reef Rocks


Thankfully, a balance of the two exists and is exactly what we recommend for new reefers. Real Reef Rock is shipped damp and has already been fully cured in clean saltwater for many months. It contains dormant bacteria that spring to life in your tank. More importantly, it really limits the risk of oddball pests and it looks great right away. The price point is right in the middle at around $6 per pound and provides a good balance of all objectives.


Real Reef Rock and Frag Rocks


Aquascaping

We chose the 55 pound box, one for each of our tanks. Using that rule of 1-1.25 pounds of rock per gallon of tank water, we will have more than enough for these 40-gallon displays. Having a couple of extra pieces around is a good idea so don’t stress on having leftovers. You will eventually use it down the road as the corals and tank develop.


Red Sea E-170 with Real Reef Rock


More or less we stacked the rock right on the bottom glass, the goal is just a stable formation which you find visually interesting and here are a few tips.


  • DON’T stack any higher than ⅔ of the total tank height because you need room for corals to grow.
  • DON’T create a rock pile or mound in the middle.
  • DO Create peaks and valleys, overhangs, arches, caves
  • Remember you are creating a habitat for fish and invertebrates and many of them prefer and need places to hide.
  • A successful aquascape does not fall down, allows the animals to hide in plain sight and looks nice at the same time.

Ryan using reef glue to secure rocks together



Pick up some of the BRS Extra Think Super Glue Gel in a tube which makes the glue easier to manage vs. the bottle. Use a generous amount on the locations where the rocks touch or connect with one another for long term stability of the structure. Clear cyanoacrylate gel is better than epoxy because of how it dries clear and can easily stay out of sight.


Caribsea Special Grade Reef Sand


Live Sand

Sand is simpler than rock and we have one specific suggestion. Caribsea Aragalive Special Grade Reef Sand because the grain size is perfect and what 90% of use here at BRS are using. The particles are not too unnaturally large like you might see with crushed coral but are also heavy enough to stay put, down on the bottom. Smaller particle sand such as Sugar Sized or Oolite will blow all over tank once you start pumping water and larger particle substrates such as Crushed Coral look terrible in most cases and get clogged up with detritus.


Caribsea Special Grade Reef Sand


One pound of sand per gallon of tank water will give you about a 1 inch deep sand bed. In this case, 30 pounds is plenty adequate for either of our tanks to create ½ - 1” deep beds. The dimension of your tank plays a role here because you are only covering the bottom panel.


1 inch sand bed


We don’t recommend anything deeper than 1 inch because you want to be able to clean it. Deeper than that is tougher to keep clean and tends to collect substantial amounts of waste and detritus, kind of like the tank’s septic system.


When it comes time to fill your tank, simply pour the entire contents of the bag around your rocks including any water that is typically inside the LIVE sand. This water contains dormant beneficial bacteria. Caribsea includes a water clarification packet you can use after filling the tank with saltwater.


Caribsea sand options


There are a wide variety of sand options and this Caribsea Special Grade live sand is simply our favorite. Regardless of dry or alive they get added to the tank the same way. Rock first then sand because you really want that rock sitting on the glass for structural stability.


We have rock and sand, now it is time for saltwater which Ryan tackles in the next few episodes starting with filtering your fresh tap water at home in Episode #9.


5 Minute Saltwater Aquarium Guide Episode #9


You can binge the entire 5 Minute Saltwater Aquarium Guide playlist right here on our website. We also invite you to join the #askBRStv Facebook Group which is a free resource for you to ask questions, get advice or simply get your daily reef aquarium fix.