Most of our tanks use the same type of substrate because it seems to work well for us. We usually use black CaribSea Eco-Complete® Planted Aquarium Substrate, CaribSea FloraMax® Planted Aquarium Substrate, Flourite® Premium Aquarium Plant Substrate or a similar product. Any other substrate we happen to have laying around such as regular aquarium gravel is sometimes mixed in.
Because these specialized substrates are highly porous we feel it helps promote the growth of beneficial bacteria and allows water to move within the substrate.
We also find that our plants do quite well and seldom need fertilizer.
We consider the substrate to be a significant part of our aquarium filtration system for the major of our aquariums. Because the substrate is used as our primary filtration system we consider it one of the most important parts of the aquarium setup.
Recently we decided to try a couple different options because of the cost involved in using the substrate that we normally choose and to see if there are any benefits to using a different substrate.
Safe T Sorb
The lowest cost substrate we found came from Tractor Supply Company.
Although not intended for aquarium use we noted that there were a few hobbyists using this material as a substrate for their aquariums.
Due to the very low cost of this product, we decided to give it a try.
It’s packaged as product use to clean up oil spills.
The material appears to be a baked clay product similar to a dense, hard clay cat litter
When we open the package it had a slight smell of oil. Because of the smell we were concerned that there may be some contamination that may be harmful to our fish however we didn’t hear of any hobbyists having an issue with it.
We tried the product in three different aquariums we found that overall we didn’t really like the product as it didn’t seem to support the beneficial bacteria that we like to have in the substrate.
We had some difficulties managing the water parameters when we used the same sponge filters that we use in the majority of our other aquariums.
We also noticed that the plants didn’t do as well. Only a few weeks after putting the plants and substrate together we noticed that some of the plants started to show signs of a lack of iron.
After trying this substrate for over 6 months in several tanks we found that with the exception of a couple of tanks the fish nor the plants seem to do well in it and we could not find any benefits for using this as aquarium substrate other than cost.
Update: After over a year of using the product we noticed that it didn’t fall apart in the water nearly as much as we expected and it looks nearly identical to what it looked like when we first started using it.
Java Moss has grown in the tanks making the water more stabile. Overall the product seem okay with the biggest issue being that there was really no nutrients in the substrate for rooted plants.
Checking the Safety Data Sheet we found that it is made of Calcined Montmorillonite Clay. Calcined according to Wikipedia is a term used for “heating to high temperatures in air or oxygen”.
Wikipedia also says that when Montmorillonite is calcined it produces arcillite, a porous material.
Black Diamond Medium Coal Slag
Another low-cost product we tried that came from Tractor Supply Company was Black Diamond medium coal slag.
This product is intended for use as a sandblasting abrasive. It seems to be completely inert and did not seem to affect the water chemistry.
After rinsing the product we found that some of it still floated on the surface of the water and we had to skim it off with a net.
Although the product looked beautiful in the aquarium we found that it was too densely packed to promote the growth of beneficial bacteria however we did like it better than Safe T Sorb.
CaribSea Arag-Alive Hawaiian Black Aquarium Gravel
Another type of substrate we decided to experiment with was CaribSea Arag-Alive Hawaiian Black Aquarium Gravel.
The substrate is designed for saltwater use and it contains aragonite our which increases the pH in the water. The package says that it causes the water to have a stable PH of 8.2.
The product advertises that it should not be rinsed as it is loaded with beneficial marine bacteria and inhibits the growth of algae. We were not sure what benefits we would see in a freshwater aquarium but we thought we would give it a try.
The color is black with the addition of some small white coloration as well. In the package, the substrate appeared to be very similar to the substrate we usually use (CaribSea FloraMax Planted Aquarium Substrate) however once we opened the package we found that it was much smaller and similar to a coarse sand.
The substrate is packaged in sea water. Although this product is intended for use in a marine aquarium, the package also advertised that it was “Ideal for most freshwater aquaria, including discus, tetras, angelfish, water turtles, rays, plants, cichlids and more“.
Because Endlers seem to do well with the addition of salt in their water and prefer hard water we thought this might be an ideal substrate to test for use in some of our Endler tanks.
We had a little concern for the plants, however, we do add salt to our tanks and our plants (Cryptocoryne wendtii) seem to tolerate it well.
At the time we decided to do the test the substrate was on sale for $13.49 (reg. 29.99) and there was free shipping when we purchased over $50 worth of product.
Although the package is a 20 lbs package the volume of substrate the volume is not as much as other brands we have purchased due to the additional weight of the water in the package.
One package seems to be about ideal for one 10 gallon tank giving about a 2″-3″ layer of substrate on the bottom.
After a couple of months of using this product, we are happy with the results. The substrate is packaged with salt water and bacteria and should not be rinsed before use.
We found that the fish nor the plants suffered any ill effects from the salt. The tanks we have used this product in are doing very well.
Because the grain size of the substrate is smaller we still prefer use CaribSea FloraMax® Planted Aquarium Substrate or Flourite® Premium Aquarium Plant Substrate however because of the bacteria that is supplied with this product we feel it is a great product for use in rapidly cycling an aquarium in an emergency.
Other Low-Cost Alternative Aquarium Substrates
So far we haven’t found an ideal substrate that can be found at a very low cost but we’ll continue working on it.