Help me out with substrate for a large tank?

[Vladka]

I’ve been on a bit of a rollercoaster and would like to get it right this time.
TLDR: help picking easyish inexpensiveish substrate for 90 gal planted tank for somewhat low-med tech plants.

I have a 90 gallon aquarium and I tried to use dirt for the first time! And it is a complete disaster!! I think that it keeps coming up through the pool filter sand and my bs plecos are also digging it up at times. I can’t see anything through the tank basically and my swords are dying. Anyways this tank was not exactly ideal with the built in overflow box and black painted back (got as an emergency when the 60 started leaking) so my family convinced me to buy a new 90 to replace it.
I have great success in my 39 using fluval stratum, co2 injections and finned planted+ light and pps liquid ferts but I’m looking for something different in the 90.
Currently I have a finnex 24/7 plant light on it, no co2 (would prefer not to add but can), and no liquid ferts but can do pps if needed. I was hoping for a cheaper set up with lower maintenance large broad leaf plants (a carpet would be a dream as well).
So my question is what kind of substrate should I use? I’ve been thinking about peat moss, balls of Mexican potting clay, and maybe some fluorite topped off with pool filter sand? Not sure how much of each but currently it’s a complete mess and I have a new tank to start over with. I don’t wanna use stratum as I have very hard tap water (ph of about 7.8-8.2) and have no interest in using RO water for a 90 gallon as I do in the 29. I liked dirt because it didn’t need co2 or liquid ferts but I can get over it.
Stock:
2 angelfish
12 bosemani rainbowfish
10 Odessa barbs
1 black red tail shark
2 bs plecos
3 dojo loaches
Some snails [emoji222]
Pics of current 90:
Before it got messed up-

After it had time to brew-

New 90:

The 29 (to show I’m not a complete idiot):

 

[King Fisher]

Black diamond coal slag blasting media is a cheap substrate alternative if you can get it where you live.

 

[ZxC]

Black diamond blaring sand, medium - large grain.
Quartz sand.
Pool filter sand.

These are all super cheap, easy to plant into, inert (so you'll need ferts, but those are easy )

They are easy to clean as well.

 

[Vladka]

I currently have pool filter sand
I love the way black blasting sand looks but all my other tanks have black substrate already and I already have all the pool filter sand I need for this tank haha.

Don’t I need a nutritious substrate for plants? Isn’t that one of the most important part of it all? I hear people always advise to do a lot of research on substrate first.
Would the peat moss and Mexican potting clay be a bad idea to add?

 

[ZxC]

I currently have pool filter sand
I love the way black blasting sand looks but all my other tanks have black substrate already and I already have all the pool filter sand I need for this tank haha.

Don’t I need a nutritious substrate for plants? Isn’t that one of the most important part of it all? I hear people always advise to do a lot of research on substrate first.
Would the peat moss and Mexican potting clay be a bad idea to add?

The only nutrient rich substrate I would recommend would be ADA aqua soil or similar products.

Water column dosing is all you need for a successful planted tank. Nutrient rich substrates are completely un-necessary, (unless you are striving for an ADA aquasoil based tank in which there is a completely different formula to go by).

 

[TMaier]

Look into water filteration media. Lots of inert cool sand like garnet and rock too. 50 lb bags are like $20. And clean!

 

[DTWGulo]

I really like Ecocomplete and Flourite (In all its various forms). It's more expensive than regular sand, but you do get some benefits to plants without having it be too hideously expensive.

I've used dirt (sand cap), Eco/Flourite, Fluval stratum, plain sand. Grown plants fine in everything. Every single system is different and there are MANY factors that contribute to success. I don't think you can isolate any single one as the only one to worry about.

Sand + water dosing + good light = Just fine for plants

If/when you wanna scale up, use the liquid carbon options (Excel, Metricide, etc.), and root tabs for root-feeding plants.

 

[ZxC]

I really like Ecocomplete and Flourite (In all its various forms). It's more expensive than regular sand, but you do get some benefits to plants without having it be too hideously expensive.

I've used dirt (sand cap), Eco/Flourite, Fluval stratum, plain sand. Grown plants fine in everything. Every single system is different and there are MANY factors that contribute to success. I don't think you can isolate any single one as the only one to worry about.

Sand + water dosing + good light = Just fine for plants

If/when you wanna scale up, use the liquid carbon options (Excel, Metricide, etc.), and root tabs for root-feeding plants.

Could you explain the benefits of inert Eco-Complete and inert Flourite?

 

[DTWGulo]

Could you explain the benefits of inert Eco-Complete and inert Flourite?

I think I see where you're going with this. "Inert" meaning that it lacks organic components that the active substrates (like ADA Amazonia), I assume?

It was my understanding that the porosity of the volcanic substrates allowed for some sequestration/storage of nutrients that are in the water column. This allows those nutrients to be available to the plant roots more readily, simply from a "distance" standpoint, but also due to the symbiotic microbial/fungal colony in the substrate.

When I was first starting out in the hobby, there was a lot of discussion about cation exchange capacity and other substrates that would 'store' beneficial substances for the plants. If I recall correctly, organics and clay have the highest CEC; sand the lowest. There is an overly broad scope to each of those types in terms of actual chemical composition. It has been too long since my chem courses for me to really dig into the underlying mechanisms here. Perhaps you could offer a refresher on this from a practical perspective?

The reason CEC was of interest was that it could serve as a reservoir for nutrients when the water column was deficient in the same. I would guess that most all planted tank people can attest to stability being one of the most important factors for success.

Straight from the company webpage: "Eco‑Complete’s™ secret lies in rich basaltic volcanic soil which contains iron, calcium, magnesium, potassium, sulfur plus over 25 other elements to nourish your aquatic plants."

Depending on which product, it may have bacteria or fungi added to the bag to help set up a good microbial environment in the substrate. How much does this help? I don't really know. The tank in which I tested substrate additives grew Hemianthus callitrichoides "Cuba" exceedingly well, but I used a range of products from the substrate manufacturer and ADA.

From a physical standpoint, the texture makes it easier to mound/scape than sand, and is more stable once scaped.

I'll grant that we have to take a leap of faith with any company's product. Your mileage -will- vary, as there are too many variables to overcome with just substrate, just light, just CO2, just fertilizers, and so on.

If you've found any of my statements that don't hold up against solid experience or, preferably, data, I'm all ears. The one thing that hasn't ever changed in my time as an aquatic gardener is that everything changes and I can always learn.

 

[DTWGulo]

I had a couple of additional thoughts that make these substrates beneficial options for beginner/inexperienced planted tank hobbyists:

Better safety compared to the soils like ADA (Early ammonia spike)
Easier maintenance if you use the versions with larger particle size.

So, ultimately, if they won't hurt, and may help, and fit the budget: why wouldn't you choose them?

 

[ZxC]

I think I see where you're going with this. "Inert" meaning that it lacks organic components that the active substrates (like ADA Amazonia), I assume?

It was my understanding that the porosity of the volcanic substrates allowed for some sequestration/storage of nutrients that are in the water column.

When I was first starting out in the hobby, there was a lot of discussion about cation exchange capacity and other substrates that would 'store' beneficial substances for the plants. If I recall correctly, organics and clay have the highest CEC; sand the lowest. Perhaps you could offer a refresher on this from a practical perspective?


Straight from the company webpage: "Eco‑Complete’s™ secret lies in rich basaltic volcanic soil which contains iron, calcium, magnesium, potassium, sulfur plus over 25 other elements to nourish your aquatic plants."

From a physical standpoint, the texture makes it easier to mound/scape than sand, and is more stable once scaped.

Great points, all of which are fairly wide spread. I'll offer my take on the matter.

Both Flourite and Eco-Complete are completely inert substrates that do not provide plant with nutrients in sufficient quantities. I've read Caribsea's statement on Eco-Complete and it confuses the daylights out of me. Volcanic rock is inert, it will not break down and supply plants with the minerals it is made out of. Yes, it contains these minerals, but they are not being released for plants to actually use. They also claim 25 elements to nourish plants which is odd because there are only 17 essential plant elements, 3 of which are sourced from water and air (not really "nutrients") -- Being Oxygen, Hydrogen and Carbon.

Now, you are correct that the CEC is a network of bonding sites along a substrates surface that will exchange and store nutrients. Organic matter (ADA style soils) will have the highest CEC and sands / gravels will have the lowest CEC. Now when it comes to Eco-Complete or Flourite, physically they are larger grained gravel with a network or pores. The actual rated CEC of both of these products are extremely low:

Flourite is number 19 - rated at 1/7 meq/100g.
Eco-Complete won't be much better as there is simply 0 organic matter and 0 clay content which are the largest CEC contributes to a soil / substrate.

I had a couple of additional thoughts that make these substrates beneficial options for beginner/inexperienced planted tank hobbyists:

Better safety compared to the soils like ADA (Early ammonia spike)
Easier maintenance if you use the versions with larger particle size.

So, ultimately, if they won't hurt, and may help, and fit the budget: why wouldn't you choose them?

Which substrates are you thinking specifically?

 

[DTWGulo]

Which substrates are you thinking specifically?

That's a great chart! (Sadly published about 4 years before I started working on planted tanks.)

...a great chart that clearly states how little CEC non-organic and non-clay containing substrates actually have.

Let's look at 19. Flourite as an example of something I've used. Flourite's CEC is 1.7

Compared to play sand -- a popular low cost option, which is CEC <0.1, there is a large numerical difference between the two.

But how much does that matter? How good is it when other non-organic substrates (such as 13. Hartz cat litter!) are so much higher? Does that 1.7 make a measurable difference in plant growth/health? I have no idea.

The only way to know for sure would be to set up a side-by-side experiment with all other factors equally controlled and see what happens. Not something I've had the time or desire to do, to be blunt. Someone probably has (Tom Barr?); I just haven't seen the results/data.

One does have to consider the action of bacteria and plants on substrates of any type. In some cases, bacteria and plants liberate nutrients from otherwise precipitated states. (Walstad, Ecology of the Planted Aquarium). Perhaps that's why the claim to provide nutrients from an inert substrate arises? I doubt that is enough on its own to overcome the deficit in CEC, though.

 

[ZxC]

Let's look at 19. Flourite as an example of something I've used. Flourite's CEC is 1.7

Compared to play sand -- a popular low cost option, which is CEC <0.1, there is a large numerical difference between the two.

But how much does that matter? How good is it when other non-organic substrates (such as 13. Hartz cat litter!) are so much higher? Does that 1.7 make a measurable difference in plant growth/health? I have no idea.

There would be absolutely 0 difference between sand and Flourite. 1.7meq/100g is still extremely low.

The only way to know for sure would be to set up a side-by-side experiment with all other factors equally controlled and see what happens. Not something I've had the time or desire to do, to be blunt.

There has been tests done (at the hobbyist level) a quick google search can produce a bunch actually (last time I checked anyway) and there is really no difference.

Supply the plants with what they need - whether that be from the substrate, or the water column -- and they will grow and thrive.

I've had tanks with Eco-Complete -- It worked well.
I have had, and currently still have, tank(s) with Flourite - It works well.

I have a tank with inert sand - It looks better, is easier to maintain and much easier to plant in to, it's way cheaper and the plants flourish the exact same if not better than in the other tanks.

 

[DTWGulo]

The side-by-sides come down to how strictly you want to adhere to experimental best practices. But, ultimately, we're not trying to grow sweet potatoes on the moon, here.

For practical applications, I doubt that the chemical composition of inert substrates makes a big difference in low-tech systems. I think it could be argued that there might be some benefits to various mixes in high-tech systems, but isolating the substrate as the only variable is not a trivial task, and is not likely to ever see any real-world benefits.

I don't personally find sand easier to plant in across the board. It depends on what I'm planting and what tools I have available to use. I also prefer non-sand substrates for aquascaping.

This was a good discussion and I appreciate the input, ZxC. Should help a lot of people answer questions about substrates. That chart in and of itself was excellent. I dug up the original magazine and cruised through it. Sorry to see that it's not being published anymore.

 

[Vladka]

Okay guys so I still think it’s worth adding something I’ll just do fluorite and peat moss under the PFS and some Mexican potting clay in there. BUT doesn’t a good substrate matter if I want a carpet? I’ve never been able to get one going with s repens or baby tears. I’d like to try Monte Carlo, any advise where to get it and if I need special substrate to do a carpet?

 

[DTWGulo]

Fertilizer, light, and CO2 are the best way to get good growth of whatever you want to grow.

I’ve had good luck with Monte Carlo and dwarf hairgrass.

Less luck with baby tears but the light in that tank wasn’t great.

 

[ZxC]

Sand would allow the delicate carpeting plants to grab hold and spread with ease.
Water column dosing is all that is needed.
Strong light and high CO2 concentrations are the 2 biggest factors in getting a carpet.

Mixing or layering substrates is of no benefit in my opinion, especially if it's inert Flourite and inert sand.

 

[DTWGulo]

Just for kicks I emailed Caribsea to ask how Ecocomplete actually benefits plants if it's an intert substrate and has a very low CEC. This is what the company rep answered:

CEC quantifies the how many cations (positively charged ions which includes the metals) are on the surfaces of a substrate of set volume and therefore are readily available for uptake by plants. The highest values are for soils that are rich in clays or organics (or both) and the pH is also a factor in this value. The CEC is hard to predict (probably because of living microorganisms in the soil) so direct measurement is the standard practice. Eco Complete is rich in neither organic matter or clays so how does a plant get access to the rich elemental composition? That’s where the Eco part of the name comes in. We include microorganisms as the intermediary between the grain and the roots. Mycorrhizal fungi and root associated bacteria secrete small amounts of acid or bases to release elements from the grains and trade them to the roots in exchange for starch and a place to live. Remember that the vast majority of aquatic plants are really emergent not truly aquatic and are therefore mycorrhizal dependent. Also, all substrates accumulate organics over the life of the aquarium and if they are not disturbed and in the case of Eco Complete, this works in your favor. If this were a quartz based material you would derive no benefit at all over the life of the system. Eco Complete is also compatible with just about anything. If you are planning a soil based system heavy in clays and organics you can include Eco and boost the transition metals that way too. Please feel free to contact us anytime with questions. We love talking about aquariums!

 

[ZxC]

Just for kicks I emailed Caribsea to ask how Ecocomplete actually benefits plants if it's an intert substrate and has a very low CEC. This is what the company rep answered:[/I]

So it’s lava rock with some added biologicals lol

 

[Autumnsky]

I got mine before they were adding mycorrhizal fungi for excellent root growth.

I have had excellent low tech growth with DHG. This was in year old Amazonia
This is just a old school style turtle bowl

11/2017

When it was started 6/2017

Also had it growing in Garnet sand about as thick in a big vase.