# Factors to consider when choosing substrates



## illumbomb (Feb 4, 2004)

Hi All,

Hope that you all could share some view on the above subject for growing cryptocoryne emersed, the factors which I currently consider which I believe are not entirely correct as I have not researched much into soil before and I have not studied biology before:

1) size of substrate particles - I will avoid substrate with too fine particles as they will seep out of pot even if I have a layer of very fine mesh covering the holes at the bottom of the pot. This should have close correlation with the packing density of the substrate also but I don’t know how this would affect the cryptocoryne (perhaps in terms of affecting root growth due to rate of exchange of air and water within the substrate or spaces for the roots to develop?)

2) I will try to match the previous owner's choice of substrate or the substrate of where the cryptocoryne are collected as close as possible to prevent possibility of cryptocoryne melt due to sudden change of environment

3) pH - I keep having doubts about this, if my water pH is very low at say 4.5 already, it is important to select an acidic soil mix (i.e. mix with peat moss) for say a peat swamp cryptocoryne or can I just use a more neutral pH substrate since my water pH is low already (I place a separate bag of peat moss in the water to lower the pH)? Does it matters that both the pH of the water and substrate be consistent since the entire pot of substrate is practically soaked in the water already?

4) porosity of particles - this probably is related to the ability to retain water, I see from the internet that many people plant their cryptocorynes in pots of substrates and place them in water up to mid level of the substrate only. To ensure that sufficient moisture is present for the cryptocoryne, substrate of good porosity (or rather good water retention capability as well as good capillary action) will be of a good choice.

5) chemical composition of substrate – this probably have high correlation to the amount and type of nutrients available. However, is this going to be important if we are adding fertilizer to the substrate already?

6) density of the substrate – There is no way of using purely substrate of lesser density than water (i.e. purely using peat moss) as there will be insufficient weight to hold the cryptocoryne firmly in place.

7) any other factors which you guys considered but I have not??????

Appreciate if someone could give a more structured guidance to the factors to be considered. Thanks a lot!

Regards,
T S Wang


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## rs79 (Dec 7, 2004)

I just use sand from the beach cause it's cheap and seem to work.


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## Yoong (Nov 26, 2007)

rs79 said:


> I just use sand from the beach cause it's cheap and seem to work.


RS,
Sand from the beach will have salt in it. Do you do multiple rinsing before using it?

Yoong


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## rs79 (Dec 7, 2004)

I live on a river in an area with lots of lakes. There's no salt for a thousand miles from here.

And rinse hell. You need to boil it. Cause, despite leaving outside all winter if you use it in the spring without boiling it then by fall you too can have one of these in your tank:










http://images.aquaria.net/invertebrates/arthropods/giant_water_bug/Lethocerus/


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## Kai Witte (Jan 30, 2006)

Come on, Richard, I bet you can spare some killis!


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## Kai Witte (Jan 30, 2006)

Actually, some of the native invertebrates can be pretty thrilling critters to observe in aquaria!


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