# Improving inert substrates



## zoon (30 Jul 2010)

Due to budget when setting up my tanks, I has to go for sand and gravel.  My 500L is mainly sand with some gravel areas ad the nano is sand.  Is there something I can poke in to the substrate to improve plant growth?  I have mainly swords and vallis in my big tank.  Was looking at JBL balls, but don't facny the price for the amount I'll need!  Root tabs have a similar problem in that I'll need lots and want to do something cheap. Was wondering if I could poke cat litter or similar around the base of the plant as I use EI ferts - would this work to absorb some of this and release it slowly?  Or am I talking total c%&@?!


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## ceg4048 (30 Jul 2010)

Hi,
   If you're dosing EI why worry about it? If you want better performance then add more CO2 and dose the water column even more. If you still want to add something to the substrate then freeze some high concentration solution in your ice cube tray, then take the cubes out and push them deep into the substrate. That'll be about as cheap as you can get. You can even get creative and add some Osmocote granules to the water in the tray. Lots of ways to pimp your substrate.

Cheers,


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## zoon (30 Jul 2010)

Will plants like swords that feed from the roots still do as well if I am dosing EI?  Sorry, plant newbie after years of cichlids (so no plants!), just figured if it was a root feeder it'd do better if nutrients were in the substrate?  Feel free to tell me I'm totally wrong!


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## a1Matt (30 Jul 2010)

Yep, they will do just as well with water column dosing (EI).


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## ceg4048 (31 Jul 2010)

zoon said:
			
		

> Will plants like swords that feed from the roots still do as well if I am dosing EI?  Sorry, plant newbie after years of cichlids (so no plants!), just figured if it was a root feeder it'd do better if nutrients were in the substrate?  Feel free to tell me I'm totally wrong!


Yes, this is totally wrong. Amazon swords are among the most voracious of water column feeders.

EI fed sword in inert sediment:






Cheers,


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## zoon (2 Aug 2010)

Thanks - just saved me money buying roots tabs or even replacing my whole substrate!


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## johnson529 (7 Aug 2010)

hi I'm also still quite a newbie but was always under the impression that root feeders like swords took their nutrients from the substrate. Now told that they can feed from the water just as well, I find myself asking why do people pay out so much for these specialist substrates?


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## ceg4048 (7 Aug 2010)

Well there are a couple of really good reasons and perhaps a few really bad reasons as well. Remember that we are not saying that plants _can't _feed from the roots, only that by definition, aquatic plants are specifically adapted to take advantage of whatever source of nutrients are available, whether that be in the sediment or in the water column. It is a distinct competitive advantage to be able to feed from both sources, so that if one area is poor in nutrients then there will be at least a possibility that another source is available. Ideally therefore we can achieve a more stable system if we provide nutrients to both substrate and water column.

So a really good reason for having a rich substrate is if you are not consistent with water column dosing due to hectic schedule (or chronic laziness.) If you miss a few doses now and again and have a rich substrate then this allows you to not be penalized. The plants simply feed from the sediment.

Another reason expensive substrates are used has less to do with nutrients and more with ergonomics. A sediment like Aquasoil Amazonia for example has a lovely feel to it, almost like velvet. If you are the type who is constantly sticking your hand into the tank to rearrange and to dig, you would really appreciate a substrate like this, as opposed to standard substrates that are coarse and sharp and which launch arrows of sharp slivers under the fingernail.

Some dosing programs attempt to minimize water column dosing due to an aversion to nutrients in general, but also to minimize the levels of TDS, which are very high when the water column is enriched. This has implications for breeding some fish which require low TDS to spawn.

So one has to understand the legitimate reasons for enriched sediments and then decide if the price is worth it. One thing that all these expensive substrates have in common is that they are usually constructed of nothing more than baked clay which has a high affinity for the very same nutrient molecules that are in the water column. The sediment particles act somewhat like a magnet for NPK and traces to a greater or lesser extent and so create a sustainable pathway by which water column nutrients are sent to the sediment and can find their way into the plant roots. This property of a sediment particle is called Cation Exchange Capacity (CEC) and Anion Exchange Capacity (AEC). Knowing this property of clay, one can then simulate the effect of the expensive substrates and root tabs by simply finding a source of cheap clay substrate and then lining the bottom of the substrate with NPK+traces prior to filling the tank. With a clever combination of water column dosing, the clay substrate and any slow release nutrient granule such as Osmocoate, one can reproduce the effects of the expensive products for a fraction of the cost. Combining this with water column dosing produces Champagne performance for beer budget.

A really bad reason for spending money for expensive substrate products is because you think that some plants can only feed from roots. That concept was developed by the Architect of The Matrix to sell more product, so that he could feed off of your hard earned cash. 8) 

Cheers,


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## robfromdublin (11 Aug 2010)

Great info.  This was something that was on my mind as well.  Good to know that having an inert substrate doesn't put me at a disadvantage.  Chronic laziness on the other hand...


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