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  • Writer's pictureBen Francis-Woodward

Why our aquatic shop fitting systems do not need regular supplementation

Shops often ask us how much biological supplementation they need to add to our Universal Aquatic Systems regularly? The answer is – you do not have to – I was asked about the science behind my claim the other day from a well-known chain of aquatic shops:

When the Nitrogen cycle kicks off and the Nitrosomonas and Nitrobacter are starting to colonise the media then supplementation of bacteria can speed the process up in the first 4 – 6 weeks. Then afterwards our systems do not need any additional bacterial supplements because our sump filter chambers have a larger aperture than standard systems allowing us to install a sump with a greater capacity to hold more water and more filter media (with different types of media), so when the systems have matured we feel if you are having to add biological supplements then the filters are too inefficient with the stock density of fish – so either one of two things; if you are a shop spending money on supplements for you filtration you need to ask yourself the question –

A) Are my systems over stocked?

Yes – this is why the filter is not coping.

No – The surface area to volume ratio in the sump media is therefore too small.

It is certainly not something practiced widespread in the aquaculture world so I see no reason why ornamental aquatic shops with far less biological load to consider should need to be doing it.

So, what can stores do to improve their existing filtration?

The first thing the store can do is calculate the surface area to volume ratio of the media being used – for instance a sump loaded with sponges –

Calculating the precise surface area to volume ratio of a sponge can be intricate, as it relies on the specific sponge material, its porosity, shape and dimensions.

To obtain a rough approximation of the surface area to volume ratio of a sponge, you can use the following method:

Calculate the volume of the sponge by multiplying its length, width, and height (for a rectangular sponge) or by using the appropriate geometric formula for its specific shape.

Estimate the surface area of the sponge by considering its external surface and the internal surface area provided by the pores. This estimation can be challenging, as the internal surface area depends on the pore size, distribution, and structure, which can vary widely between different sponge materials. Some manufacturers may provide an estimated surface area for their filter sponges, which can be useful for comparison purposes.

Divide the estimated surface area by the volume to obtain the surface area to volume ratio.

Bear in mind that this approach provides only an estimate, as it does not account for the complex internal structure of the sponge material.

The most common answer to the above is 200m2 per m3.

Our sumps contain media that is 800m2 per m3 in an area with a greater water volume and thus this is why our systems are more efficient than an industry standard sponge filter type sump with a handful of bio balls and why you do not need to supplement our systems with bacteria after they have matured – because there is enough surface area of media to cope with a standard stock density of ornamental fish with a sensible feeding regime -

So if you are a shop using supplements - calculate how much you spend on them per annum, it might be a passive cost you have not thought about when choosing who to install your aquatic shop fitting systems.

over feeding and overstocking can of course still lead to poor water quality in all systems.

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