# Substrate Questions



## JOE32 (13 Sep 2008)

This is my first post here, Fantastic forum by the way,I have been a lurker for sometime and have learnt a hell of a lot.
I am geeting a new tank for Christmas, Thanks to my darling wife she might look in   
The new tank will be 8x2x2.Having looked how much eco complete I will need goind to be in excess of 300 lb so that is at least 15 bags   .
I have a Rio 400 at the moment that has Eco as the substrate topped off with black sand,The EC has been in there around a year.Will there still be any nutrients in the substrate or will it be basically inert by now ? I would like to add it to the new tank and help keep the costs down but will it be of any benefit to the plants now.Is there any way to remineralise it so to speak if it has lost most of the good stuff in it(sorry for not being very technical)
I really like the look of the EC but dont want to have to shell out for another 15 bags. 
What I dont want to do is find out 3 months down the line that I should have changed it all as the plants are not doing well as that will just be a load of hassle.


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## GreenNeedle (13 Sep 2008)

My personal opinion is to mix it with the new.  As long as you are water column dosing it shouldnt matter.

AC


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## aaronnorth (13 Sep 2008)

you could go with akadama if you are not bothered about black substarte:

viewtopic.php?f=17&t=741


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## JOE32 (13 Sep 2008)

Thanks for the advice, I have had a read of the thread re Akadama and it seems good.
But I really like the look that the black substrate give the tank, everything just seems to stand out more with the contrast against the black.
Well maybe I will have to bit the bullet and go with the eco complete after all.


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## aaronnorth (14 Sep 2008)

you could get some activated acrbon and use it as a layer under the EC to try and cut costs, or just some normal black gravel


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## jay (16 Sep 2008)

Thats a big tank.
I would just mix up your old substrate with a few bags of new EC and some inert small grain gravel.

plants will grow fine if you dose the water column well. Would invest in dry ferts for a tank that size  

Good luck!


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## ceg4048 (16 Sep 2008)

Also, it's important to determine what goals you have with the tank as this can affect the options you select. Goal number 1 is to decide whether the tank will be high tech or not. If you are opting for a non-injected low tech approach then ordinary potting soil can be used topped with EC or black inert gravel. If the tank will be injected then as Jay notes, the water column dosing will render substrate choice less critical.

Cheers,


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## JOE32 (17 Sep 2008)

The new setup will be high tec to a degree, I will be injecting CO 2 into the tank and will be doseing EI as I am on my current system. I am aiming for around 2.5-3 watts per gallon although I know the WPG rule does break down somewhat with bigger tanks but I think the lighting will be OK for almost everything I want to grow.
Just one other question regarding substrate, why do some people put a layer of Spagnam Moss under the substrate, what benefits does it give you?


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## ceg4048 (18 Sep 2008)

Any organic matter placed in or under the substrate such as sphagnum, peat, Leonardite, mulm and so forth provides carbon for the sediment bacteria. This is one of the least appreciated yet one of the most important issues affecting the stability of a tank. The sediment bacteria do a lot of nitrification and the substrate colony is as important as the colony in the filter. 

Just as plants need carbon from CO2 and we need carbon by ingesting bread so the bacteria require carbon for their structure. Bacteria have no mechanism to pull carbon from CO2. That can only be done by plants/algae. In a mature tank the carbon will be provided by the plants via their leaching of carbohydrates, proteins and so forth as well as bits and pieces that fall off. Foodstuff and organic waste from fauna also contribute to the carbon production.

So there is a symbiotic relationship between rooted plants and sediment bacteria. In a new tank the sediment bacteria are limited by the unavailability of carbon because the system isn't yet up and running. Plants are struggling to adapt to having been flooded and if new substrate is being used there is very little for the bacteria to eat so their population buildup is not as rapid as it should be. This leads to ammonia buildup due to inefficient nitrification which then leaches into the water column. 

Any carbon source we can add helps to feed the sediment bacteria. Anything organic consists of carbon so this is why we add mulm from the substrate of other tanks or from other mature filters to a new sediment bed or filter - not just because it contains bacteria to seed the filter/substrate, but this mulm is full of organic carbon on which the bacteria can feed more efficiently.

The flip side of this relationship though is that after the tank has matured, there is then too much organic carbon production and this then decays causing ammonia production. This is why we have to do water changes and filter maintenance to pull excess carbon production out of the tank. This is why dirty filters and poor maintenance often results in algae in high tech tanks.

Some typical examples of commercial products that provide organic carbon which can be mixed with or under inert sediments like sand or gravel are:
Ferplast Substrate
Tetraplant
Tropica Substrate

The marketing departments dream up all kinds of poetic phrases to impress but essentially, lets face it they are more or less rotted leaves, just like you sphagnum moss will be after a while. It's very amusing because you can tell by certain words in the description like "Humic Substances" or my personal favorite "Vegetable Physiology". At least the Tropica description is honest as they spell out exactly what's in it.

Enriched substrates such as ADA Aquasoil, JBL Proflora and possibly Ecocomplete have organic substances like peat mixed in with inorganic nutrients so they don't require the addition of carbon additives.

Cheers,


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