Question of the Week Are you ignoring your substrate?

[Art]

Should we think more about our substrate’s impact on your aquarium’s ecosystem?

The substrate you use is:

• home to a huge system of bacteria and other microorganisms;
• the toilet bowl of your tank;
• a nutrient storehouse and processing plant;
• the home and food location for plant roots; and
• an aesthetic piece of the overall aquascape.

Be honest. Do you factor the above points into how you setup and maintain your tank? Should you spend more time thinking about it?

For example,

1. Should you use more root tabs and less liquid fertilizer?
2. Should you use an organic substrate rather than inert one?
3. Does color play a role in the ecosystem?
4. Does gradual size matter?
5. Should you clean it every time you do a water change?
6. Are multi-layered substrates like PowerSand and AquaSoil better?

It’s a new week! Happy Monday!

Let’s have some fun sharing our thoughts and experience on the above this week!

 

[ElleDee]

I don't think the substrate is ignored exactly, but it can be complicated and is not well understood.

My experience in the hobby points strongly to the importance of the substrate in achieving a mature, stable aquarium - the magical "balanced" state where problems are small and you just do basic maintenance and enjoy - but I don't know how to really apply this knowledge in a useful way.

I spent a lot of time reading and thinking about the substrate for my big tank because I wanted to do a diy nutrient layer. I have an MS in horticultural science and my foundational knowledge in planted substrates is pretty good. But in the end I still felt like I was guessing about stuff. They were educated guesses, there was a reason why I made every decision that I did, but I didn't know if it was going to come together like I wanted. There were so many aspects where I was aiming for a sweet spot, so there was a risk of both over- and undershooting.

And now that the tank has been running for a while it seems like the substrate system is going well (yay) and I am pleased about that, but could it be even better if I had made different choices? I have no way to evaluate that.

 

[Art]

What choices were you considering?

 

[ElleDee]

Ok, you asked!

The main issue was in figuring out which components to include and how much. Organic matter in particular is such a double edge sword, which we've talked about here at various points - it provides CO2 and nutrients as it breaks down, has CEC that generally surpasses all mineral soils, and contributes to a biologically active rhizosphere, but excess organics seems to bring pernicious algae, plus it greatly increases BOD of the tank, which could lead to water aeration issues, hydrogen sulfide production, etc. With such major positive and negative effects possible, what do you do?

At one point in the planning process I made this chart detailing the different substrate components and what I thought each was bringing to the mix:


This was rudimentary brainstorming, so no laughing! You may notice I don't have any quantities for anything, because I just don't know what they are. The whole soil structure column is speculative because I don't know how it translates to permanently flooded soils. I do suspect that it's an underappreciated aspect in the hobby, but I am acutely aware I have a knowledge gap.

I should clarify my earlier post a bit:

My experience in the hobby points strongly to the importance of the substrate in achieving a mature, stable aquarium - the magical "balanced" state where problems are small and you just do basic maintenance and enjoy -

It's not just the substrate, but the plant roots, the bacteria, the soil water and the interactions between them that is important, at least in the type of tanks I run.

but I don't know how to really apply this knowledge in a useful way.

I mean that I don't know how to apply this knowledge in a useful way beyond what has already been done by others. I can't resist the urge to put my own spin on something, and I feel like with my background I ought to be able to, like, deepen my understanding or contribute something useful eventually. Maybe I'm just reinventing the wheel, but hey, then I have a wheel I made myself.

 

[Phish Tank]

I do think about substrate impact, but I've only done inert in my big tank (tried sand, now it's gravel). Sand was so hard to clean and always looked dirty. I'm much happier with gravel, and it let's me keep UGF plates under half the tank.

For some reason I feel like aquasoil would add another variable i can't control to the tank. I also am keeping a medium energy tank, and felt like aquasoil would put the tank in overdrive.

Recently I set up my first nano tank with a thin layer of potting soil, covered by a thin layer of sand, topped with a thin-ish gravel layer. Jury is still out on if I like it.