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Sand as a substrate


28 Mar 2008
Guildford, Surrey, UK
I really like the look of sand in my tank and want to keep this when I upgrade my tank (120l arrives on Sunday). Now I've already got the sand (being a student I picked up the cheap kids play sand from Argos), last time I put pond soil underneath it. This works ok but because it's soil it eventually works its way to the surface, especially during rescapes!

What I want to know is what's the best way to proceed, do I find an alternative substrate to go under the sand, one which is less biodegradable and less likely to mix or should I go with just sand and get some root tabs for my crypts etc. Unfortunately I do have a rather tight budget for this (I probably wouldn't even be doing it but the seals in my old tank have become suspect and there was a barginous one on ebay) so I really don't want to end up spending a fortune.

Any advice greatly received.

*edit* Forgot to add that since I'll be replacing my old tank this will be an in-and-out job so substrates that leech ammonia are probably out of the question.
You forgot to indicate whether this is high tech or not. In a high tech tank just use the sand by itself, dose the water column like crazy and forget about it. If this is a low tech tank then you'd maybe want to put down a layer of peat or compost.

Oops :oops:

I only have DIY CO2 at the moment (though the plan is to go pressurised towards the end of October) and I'm using DIY TPN+ with extra phosphates, will prob be about 20ml per day. The tank itself is 120l and comes with a 25w T8 lamp. I'll be adding in extras as I find I need them (I have 3 15w controllers in my current set-up that can be moved over)... so basically it's low tech at the moment but will probably end up being higher tech later on!
Nope, adding CO2, DIY or otherwise, makes it a high tech. That's because CO2 accelerates growth rates far beyond what is achievable with non-CO2 methods.

Ah, ok, didn't realise that.

I think I'm going to go with an akadama like thing called J Arthur Bowers Hydroleca. It seems to have the required high CEC value without being either exceptionally expensive or annoyingly crumbly :)

My theory is to rinse it then 'prime' it by soaking it in some water with added ferts. If/when it does end up coming through the sand then I can just pick out the balls as they appear. This is all provided my local B&Q has it in stock!
Well that was a complete failure. It turns out that Hydroleca is annoyingly buoyant, even when it's been soaking for several hours. So now I've just got plain sand and I'll add root tabs under the heavy root feeders if they look like they need it, otherwise I'll just fertilise the water column heavily and see how it goes. Cheers for the help Clive.
Hi Egmel,
If I were you I would just dose the water column and forget about root tabs. The so-called root feeders actually feed from the water column just as much as any stem plant. If you are adding CO2 they will need it. CO2 increases the uptake demand tremendously. Neither Cryptocorynes nor Echniodorus have gone through the trouble of evolving into aquatic species just so that they can feed from the roots only.

Here is an example of C. wendetii when fed properly from the water column. These leaves are over a foot long but they wouldn't have gotten that size that quickly if I were to just depend on substrate feeding alone. If CO2 molecules can diffuse through the leaf structure then so can K+, NO3 and PO4 molecules. Feed your plants by dosing the water column. Root tabs are an illusion.

Thanks Clive, as usual a well illustrated explanation :D
I have been skeptical of the whole "heavy root feeding" line myself, Clive. I am growing Pogostemon helferi and Cryptocoryne parva in inert sand no problems. The water column is EI dosed.

My Tropica substrate must be already or very nearly 'spent' seeing as it is now 1 year old. The tank only has 'heavy root feeders' (I agree with Ceg on this statement.)

As a small question r.e. Hydroleca. What made you go for the Hydroleca rather than Laterite which is widely used in aquascaping?

SuperColey1 said:
As a small question r.e. Hydroleca. What made you go for the Hydroleca rather than Laterite which is widely used in aquascaping?
Cost (a false economy it seems) Hydroleca is about £2.50 a bag and had it worked I would only have needed 2 bags for my 125l tank, laterite is substantially more expensive.