Part: 2 Thermodynamics Substances:
Bead filters along with filters like the Nexus are subject to the medium that is used in them and how much usable surface area they have available to the bacteria. The golf ball dimpled plastic media I talk about in the first part, really sounds more promising than just a smoother surface media. The surface of the media should have more of an irregularity nature to it to aid in increasing the polymeric surfaces tension properties aiding in accelerated bacterial colonization of the media.
Plastic mediums always have a longer lag time before colonization with bacteria until a polymeric surface is established to prevent water shearing. This bacterial made polymeric adhesion now made up of dead cells makes the media not only heavier i.e., which is demonstrated with the bio-wheel filters slowing down to the point it may stop altogether, now becomes a sticky substrate for micro particles to adhere to in solution. Now, not only does the medium become a biological filter but it also becomes a collective micro mechanical filter too. Whenever a filter changes it structural integrity from biological to mechanical, that’s when compromises are instituted within the filters medium. Now you have the burden of constantly cleaning the media and it has to be exsiccated also or unwanted ammonia, phosphates and Nitrates will be its byproduct. It’s not that the mechanics of these filters like the Nexus are badly designed, they are not, (in fact a Nexus tries to separate the two in one filter mechanism) but the media inside them becomes the limiting factor reducing bacterial availability.
If you look at what is respectability represented out there for filtration mediums the choices are almost unlimited. In fact one manufacturer that makes plastic medium went as far as to add a small black sponge encapsulated in a spherical plastic unit. The idea sounds good on paper, but in real life it just becomes a biological and mechanical filtering media just the same. It is a pain in the conquistador to take them apart and clean that little sponge that’s in the center of them when they clog up with detritus. When new they are abundant in microorganisms do to the particulate polymeric substrate surface tension, but that is short lived do to clogging because most of the medium are used in a static state and not an activated state so detritus can easily settle on them and clog them.
The photo above shows some of the plastic filter mediums available to the hobbyist. The spherical plastic balls are not really meant for pond use but for aquarium filtration wet-dry filters.
The sponge did achieve the desired surface meter squared area desired along with a good advertisement campaign in aquatic magazines but not in real life circumstances. I know of hobbyist that used (past tense) this medium and in the end because disgusted when cleaning time came.
When it comes to the King of surface area to size of particulate matter the Activated Carbon is on top of the heap! One gram has 500-1500m2 (one gram is about the weight of a paperclip) of surface area and this can be increased even larger in some cases depending on manufacturing processes. Due to its very small microporosity it’s not really a good biological filter media for the pseudomonadales Nitrobacteria that hobbyist are looking for. Other sintered silica base mediums have been made with slick advertising on the correct microporosity of the unit, but once again the hobbyist through trial and error found that they did not live up to the task that they were designed for. Some even made the claims of dissimulative denitrification of NO3 reduction but they clogged and this denitrification process was rendered useless within a short period of time. You can still buy these mediums today but the experienced hobbyist(s) avoids them. I have boxes of this stuff at home but its uses now are basically for mechanical prefilterlazation and not for biological purposes, at least not for denitrification.
There are other biological mediums out there, some made from plastic or some other synthetic material that is to increase the longevity of the media and to slow down deterioration of the medium before it must be replaced. Such synthetic materials work in particulate polymeric substrate surface tension and apply to the laws of thermodynamics substances but the number of cells differs from media to media and can change drastically with time and the changing of the surface tensions of the adhering particles to the substrate because of clogging.
Though the available clogging of the surface of the media is all on a micro level, some hobbyist will not even give it a second thought until water parameters becomes depredated enough by chemical and biological insults. It is only then that the hobbyist will finely take action in the form of water changes or medication restitution i.e., feeding your Koi garlic impregnated foods the rest of their lives to ward off sickness or keeping them in salt brine continuously because they’re once again afraid of nitrite toxicity because of inadequate biological filtration. Some hobbyist will use the excuse of a salt prime because of parasites but even this gets to be a little lame after a while because healthy fish seldom, if ever, gets infested with parasites. Does it really have to get to this point of using an axiological approach to prophylactics sublimations instead of lets just fix the problem…I guess so!
Read part one, below link: