Silica sand is a lighter tan and is very uniform and fine in grain size. It cleans very easily and provides a nice look , itís very afffordable and can usually be found for 10 dollars or less per 100 lb. sack.
Play sand is also very affordable and is darker and less uniform in grain size & color than Silica sand. It contains a fair amount of clay and can be quite dirty compared to Silica sand. As long as you take the time to thoroughly rinse the sand it makes a good substrate.
Black Beauty is another affordable sand used for sand-blasting and is sold at home supply/hardware outlets. Itís not really sand but powdered iron slag. It can be quite sharp so itís not recommended for fish that sift a lot of sand such as Tanganyikan sandsifters. Furthermore, these very fine particles contain iron, which means they are not inert.
Coral Sand is an off white color, lighter than the previous sands, and less uniform. Itís a bit rough to the touch but is a good choice if you need to stabilize your PH or improve your buffering capacity. Itís fairly expensive compared to the previous types but less than Aragonite.
Aragonite is a sandy substrate available in several colors and grain sizes, itís similar to Coral sand as far as buffering goes, so itís a good choice if you need help with buffering. Itís quite expensive, so you may want to consider another choice if you have a large tank to fill.
Lastly, a newer sand is now available that is a nice black color, very uniform and much safer than Black Beauty. Itís Black Tahitian Moon Sand, itís a great choice if you want the black sand, but itís expensive (similar to Aragonite).
Once youíve decided to switch to sand and have picked out the variety, you need to prepare it for the tank. I recommend only a 1-1.5" depth of sand throughout the tank, it can take a lot to maintain a real deep bed and can cause problems which Iíll explain later on.
With the exception of "Live Aragonite" (sand thatís pre-seeded w/ living organisms/bacteria) youíll need to clean your sand. Donít cut corners here; itís time well spent. Get a 5 gallon bucket and a garden hose with sprayer attachment. Pour about 2 gallons of sand into the bucket and fill the bucket with water, pour the excess dirt film from the bucket, then really churn the sand while giving it a high pressure spray, this will get most of the dust, etc, off the sand. Pour the dirt film again and repeat until youíre pouring clear water. If you choose Play sand or Black Beauty this can take several tries before itís clean enough. I get a 30 gallon trash can and line it w/ a couple trash bags to pour the clean sand into. Just repeat this process 2 gallons of sand at a time until you get all the required sand clean.
If youíre switching from gravel to sand thereís a couple ways to make the switch. If you have a small tank and want to remove the fish while doing the change-over thatís fine. Larger tanks w/ a lot of fish is easier if you leave the fish in while changing over. I like using a large filter bag to load the gravel into, you can also use a spaghetti-strainer bowl or nylon hose. Anything thatís safe and porous will do. If you donít have much bacteria filtration in your tank you may want to keep some seeded gravel in a filter bag or nylon hose so you can aid your sand substrate in establishing bacteria levels, just put the bag near the filter intake and you should get good results after about 5-7 days.
When the gravel is removed BE SURE to shut down any impeller operated pumps & filters. Youíll have a lot of sand floating around and it can really do some damage to your equipment. When adding the sand if youíve left your fish in the tank, be careful not to add too much at once. It can clump together and become a "depth charge", splashing a lot of water and stressing the fish, just be patient and careful here. Once your sand is added and youíve got it leveled out and the tank arranged to your liking, go ahead and turn on your pumps/filters.
Another thing to keep in mind: If youíre cleaning your sand with very cold water, or leave the sand overnight in the cold, the sand can cause a quick temperature drop when added to an existing tank and shock the fish. Be sure to keep the sand in room temp for awhile to get the sand temp back up or add some warmer water to the sand. This usually isnít a problem, but itís something you should be aware of.
Maintaining the sand bed can seem like a challenge to those that havenít tried it. Itís actually very easy once youíve gotten used to it. Hereís the procedure I use and itís worked well over the years:
Every 2-4 weeks, depending on your fish load and available time, a good skimming of the sand should be performed. A small vinyl hose works well, about the inner diameter of a garden hose. Just hook the hose up to a faucet pump and siphon up the surface detritus. You may siphon a lot of sand the first couple of tries, a little practice is all it takes. Just keep the end of the hose about Ĺ" away from the sand and quickly siphon up the fish waste. No need to remove or re-arrange the rocks, just get all the visible sand areas. Try to get the entire "visible" sand floor.
Every 8-16 weeks, again, depending on fish load, a good churning of the sand bed is required. Trapped food and gasses can become toxic over time and these need to be released periodically. Youíll notice that there will be a statification of the sand bed. The bottom "trapped" layer of sand will turn a dark grey-black in time, and once the layer is churned up and the waste & gasses released, it will eventually turn back to the original sand color. Youíll even notice a bit of "rotten-egg" odor when churning the bed, this is normal and are just the gasses being released. At this time you should also move rocks and churn the sand under them. You may want to do half the tank at a time so there wonít be as much disturbance. Youíll have quite a cloud of debris, so youíll want to let it settle and do a good skimming again. Be sure to keep all impeller-operated equipment off during the churning procedure.
One last note, when keeping sand in Acrylic tanks, be extra careful when cleaning the surface and using algae-cleaning magnets. A single grain of sand between your cleaning sponge or magnet and the acrylic surface can be very damaging.
Hope you enjoy sand as your substrate! □