Deciding on a substrate


Junior Poster
Nov 13, 2007
I am starting a 65gal, and am trying to decide on a substrate. I'm a believer in doing it right the first time, so if I need to spend a little extra money, that's ok, but! that doesn't mean I want to waste money for the overhyped latest and greatest. I narrowed it down to Flourite, Aquasoil, and Soilmaster.

Since all of these a clay based, my first question is do I need a substate that is pre-loaded with nutrients. Yes, this might help initially, but can Flourite and SMS be soaked in nutrients so that they absorb? Is this really important, or just marketing?

Is the iron in Flourite important and can it be replaced by iron supplementation in the water column. Do certain plants require iron at the root level vs. water column?

Do dyes in SMS effect it's porosity and therefore it's CEC?

What is the difference in their respective weights, and is this a real difference or just a personal preference?

Also, is there any possible combination of substrates that would be "ideal"? I know that's subjective, but I was considering Flourite black with SMS charcoal, totally mixed, not layered. I don't want a layered scheme, due to be mixed up eventually.

This ends up being a cost benefit analysis. I like aquasoil, but when I include shipping, the cost skyrockets, so I'm questioning whether the benefit outweighs the cost?

Thanks for any and all input!!!!



Plant Guru Team
Lifetime Member
Sep 23, 2007
South Florida

All three are good, but a lot depends on other factors:

1. What type of setup? tank size, c02 fert or no? Slow growth, low maint?

2. High light, low or med? CF, MH, ??

3. Your goals. Do you want a heavily planted tank, or not?

I think with some more info, you will get a more tailored response.

Is the iron in Flourite important and can it be replaced by iron supplementation in the water column. Do certain plants require iron at the root level vs. water column?

My understanding is that plants will take nutrients as they can get them, some more from leaves and roots than others.

If you do not plan on additional water column fert, then maybe a nute based substrate would be better for you in the long run.

I use flourite and have been able to grow anything that I have placed in there.
I just started water column fert (EI) but before that nothing, but still had 'decent' growth.

Hope this helps a bit.


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
Sacramento, CA
I would start by deciding which substrate material looks the best to me. Then I would decide if I am the type who needs the crutch that ADA soil provides for absent minded fertilizing - forgetting to do so many times. If I were that absent mnded I would want the ADA soil, if I liked the color. If not, I would probablly use SMS, accepting that it may depress the KH of the water for awhile. Since you listed only black or dark gray substrates I assume that is what you want. Finally, I would look for a place to buy 3M Color Quartz black sand, to see if it is economical. If so, and if I didn't want the fertile substrate, I would use it, because it is heavier and easier to plant in.

SMS is very light weight, and at least when first added to the tank, it doesn't hold small rooted plants well at all.


Junior Poster
Nov 13, 2007
To be more specific on my intended tank, 65 gallon 36 x 18 x 24 tall, it will be a psuedo biotope aiming toward Rio Guapore in S America with apistos. Pressurized CO2, fertilizer supplementation, high tech, 6 T5 HOs, RODI water, heavily planted, clear water (vs black water). Haven't really decided on color of substrate. I want artistic, but probably more important is function.



Guru Class Expert
Jul 9, 2007
Austin, TX
I'll cast a vote for Aquasoil. I haven't used the other substrates you mentioned, except for plain aquarium gravel, so my vote is sort of biased. As opposed to gravel, aquasoil is very easy to plant in and looks very natural, in my opinion. It reminds me of pond silt, in tiny pellet form. It is very light, but still holds plants well, and is gentle on the stems. It is also very nutritious and my plants just love it. You dont have to worry about "charging" it with NPK beforehand, and as Hoppy mentioned, you dont have to be as strict with your fertilization. There's a little more room for error. It does lower the KH of the tank water and can possibly leach tea-colored tannins. But the tannins quickly stop leaching after a few weeks/months, and the water will stay clear. Another con regarding Aquasoil is that you cannot really replant or rescape your tank a lot. Disturbing the substrate will send a bunch of particulate/silt into the water column and make it cloudy. This too is not really a problem, because the filter will take care of the sediment, and it settles back down fairly quickly. I think the soft, clay "pellets/balls" are also safe for bottom-dwelling fish such as Corydoras, Loaches, etc. It won't damage their barbels, and I think the microorganisms that live in the dirt/substrate/soil are beneficial to them/their digestive tracts. I could be wrong, however. I'm no fish expert. But my pygmy cories are doing fine.

The only real issue I had with aquasoil is during the tank startup. Aquasoil really does leach a bunch of ammonia and organic compounds into the water. It does this for about a month. You will have to do large waterchanges every few days, as well as use mulm from a preexisting tank, zeolite in the filter, activated carbon in the filter, and plant many plants from the start. All these will reduce the problems with the initial ammonia and dissolved organic compounds that Aquasoil causes.

Even with the initial challenges of using Aquasoil, I still reccommend it. Its asthetics --color, texture, feel-- are great. It comes in 3? different colors. Its functionality and benefit to the plants are obvious to me as well. My HC grows great in the stuff.

Pricewise, I think Aquasoil is worth the investment. Yes, plain gravel/sand is cheaper and easier to find, and will grow plants fine -- but Aquasoil does have its advantages. I ordered mine from Aquarium Design Group. -- They have a great price and various shipping options. They are in Houston and if you live in central to east US, their shipping would be cheapest/quickest. If you live west US, shipping from AquaForest in California would be cheapest/quickest. And they have prices on Aquasoil just as cheap as ADG.

Either way, good luck with your tank and have fun setting it up!
-Mike B-

Tom Barr

Staff member
Jan 23, 2005
Given the goals and your input, ADA Aqua soil sounds right for you.

Tom Barr