Ehfimech

[waterdrop]

Ok Raptor (BBB ) I know when I'm out-described! I think I'm buying your argument. The contribution of the smaller amount of bacteria just due to the ring surfaces having some grip is probably too subtle to warrant the amount of credit I've been giving it as being almost as much a biomedia as it is a mechanical media.

Your description of the way that the coarse blue sponge "caps" the ceramic rings, creating a trap for all the larger organic debris and forcing it to be trapped or fall back down into the large open-water area below the bottom-most basket is really excellent and I admit I'd not thought of it that way and now see it as more clever than I'd previously pictured. And you're right, letting it have a place to hang around and decompose into ammonia would be important and I'd not really thought about that free area down there as so clearly serving that role in the system.

Thank you for sticking to your argument, I was being stubborn but now definately feel I've gained a more refined understanding of the design goals seen in my own filter.

You are also now causing me to question the correctness of the term "ceramic gravels" that has been mentioned on the forum. I wonder if virtually all (or some of the time?) instances of these "gravels" are really sintered glass. I know that Seachem Matrix and some of the others are. Aren't both Substrat and Substrat Pro made of sintered glass?

~~waterdrop~~

you know, WD. until you asked, i had no idea what substrate and Pro, were made of. lol but, yes, it's sintered glass. but, that is ceramic. though that may seem odd. sintering is the process used to fuse partials together, under pressure, with heat. but below the melting point of the medium. its the make up of the glass (components used that are not silica) that produces, "sintered glass ceramics". I'm with you on the Ceramic Gravel thing. that would, to me, be "sintered glass". though Seachem Matrix is a natural stone. honest! and, would seem to have massive surface, area/volume. many many times more than Eheim substrate pro!
here is a review. though i know its from Seachem. it still makes interesting reading. Matrix v substrate pro and Micro Mec.

Raptor, I actually have several more topics I think would be interesting as offshoots of this discussion (haven't time now but remind me later some time) .. basically they fall into two categories:
1) The progression from our desired autotrophs to facultative anaerobes and then to obligate anaerobes as the oxygen flow becomes too restricted either due to inadequate fresh water flow far down in a given individual piece of biomedia or due to too tight a media packing or too large a media bed. An interesting part of such discussion would relate to the importance of the "crush factor" in media type and packing. Some media can maintain a fixed spacing whereas other biomedia types can be subject to crushing and loss of flow space.
2) The whole topic of how much biomedia surface area is "enough!" After all, experienced aquarists can often coax out a balance between the stocking load and a small cheap filter with a minimum of available biomedia surface area. You and I know that big beds of high quality biomedia in a well-designed filter that has a higher media volume are much easier to use and more reliable in practice.. but an interesting question is at what point the whole hobbyist/supplier discussion of greater and greater surface areas becomes overkill on a practical level (interesting topic, don't you think? )

~~waterdrop~~

 

[raptorrex]

Raptor, I actually have several more topics I think would be interesting as offshoots of this discussion (haven't time now but remind me later some time) .. basically they fall into two categories:
1) The progression from our desired autotrophs to facultative anaerobes and then to obligate anaerobes as the oxygen flow becomes too restricted either due to inadequate fresh water flow far down in a given individual piece of biomedia or due to too tight a media packing or too large a media bed. An interesting part of such discussion would relate to the importance of the "crush factor" in media type and packing. Some media can maintain a fixed spacing whereas other biomedia types can be subject to crushing and loss of flow space.
2) The whole topic of how much biomedia surface area is "enough!" After all, experienced aquarists can often coax out a balance between the stocking load and a small cheap filter with a minimum of available biomedia surface area. You and I know that big beds of high quality biomedia in a well-designed filter that has a higher media volume are much easier to use and more reliable in practice.. but an interesting question is at what point the whole hobbyist/supplier discussion of greater and greater surface areas becomes overkill on a practical level (interesting topic, don't you think? )

~~waterdrop~~

Both, these, are areas i need to look into. I think one thing we can put aside, for now anyway, is "crush factor". for sintered ceramic media anyway. if these media are "squashed", they collapse, not compress. lol. in theory, that would give more surface area. but it would be coupled with a, massive, restriction of flow.
I said, "put aside" because, the way media is packed into its area, could well have significant effect on its efficiency. i have a sneaking personal view that, media needs to "move" whilst doing its job. well, to be truly effective. however with sponge media, i feel it is of great importance. again, personally. if a sponge needs, compressed/squashed, to fit in its area. the sponge is too big, so i cut it down.

Aha, but now to the meat , bio media volume, and water "dwell time". but perhaps we need to make another thread, before i go into that any further. what you think WD? we are, already, well out of Ehfimech, territory.

 

[waterdrop]

Raptor, I actually have several more topics I think would be interesting as offshoots of this discussion (haven't time now but remind me later some time) .. basically they fall into two categories:
1) The progression from our desired autotrophs to facultative anaerobes and then to obligate anaerobes as the oxygen flow becomes too restricted either due to inadequate fresh water flow far down in a given individual piece of biomedia or due to too tight a media packing or too large a media bed. An interesting part of such discussion would relate to the importance of the "crush factor" in media type and packing. Some media can maintain a fixed spacing whereas other biomedia types can be subject to crushing and loss of flow space.
2) The whole topic of how much biomedia surface area is "enough!" After all, experienced aquarists can often coax out a balance between the stocking load and a small cheap filter with a minimum of available biomedia surface area. You and I know that big beds of high quality biomedia in a well-designed filter that has a higher media volume are much easier to use and more reliable in practice.. but an interesting question is at what point the whole hobbyist/supplier discussion of greater and greater surface areas becomes overkill on a practical level (interesting topic, don't you think? )

~~waterdrop~~

Both, these, are areas i need to look into. I think one thing we can put aside, for now anyway, is "crush factor". for sintered ceramic media anyway. if these media are "squashed", they collapse, not compress. lol. in theory, that would give more surface area. but it would be coupled with a, massive, restriction of flow.
I said, "put aside" because, the way media is packed into its area, could well have significant effect on its efficiency. i have a sneaking personal view that, media needs to "move" whilst doing its job. well, to be truly effective. however with sponge media, i feel it is of great importance. again, personally. if a sponge needs, compressed/squashed, to fit in its area. the sponge is too big, so i cut it down.

Aha, but now to the meat , bio media volume, and water "dwell time". but perhaps we need to make another thread, before i go into that any further. what you think WD? we are, already, well out of Ehfimech, territory.

Yes, I was thinking of crush factor in the sense of it being an advantage to stiff media like gravels or ehfisubstrat pro rounded media (as long as their media bed volume is large enough) as they would be expected (as long as they were not allowed to get too clogged) to maintain fixed openings for good water flow. I actually think (and have read) that plastic scrubbies are also better at this than one would think, due to their considerable stiffness. Very coarse sponges would be similar to scrubbies in this regard but as you moved in the direction of less coarse or, more specifically, less stiff sponges, you'd start to get into the range where crush factor would matter. I agree with you that as you get into softer sponges you need to pay attention to not crushing them into their media tray space too much.

On the other topic, "how much surface is enough," I'd take a guess that we could imagine 4 divisions, to picture it:
1) Not enough or barely enough surface area to support sufficient colonies to match the bioload
2) Sufficient surface area but not much extra surface area to spare.
3) Extra surface area available in the biomedia volume in sufficient amount to handle any extra needs.
4) Excessive biomedia surface area such that money is wasted, given the bioload limitations of the tank.

So number 3 above is the interesting one, don't you think? If your filter size choice has achieved #3 then there'd be the obvious benefit of it being able to easily handle an increase in bioload fairly quickly. But I wonder if there are other unconsidered benefits? Perhaps a given patch of biofilm has a "lifetime" and the autotrophs cyclically abandon (or they die in it) it and begin in a new patch of surface area. Then, eventually, that dead patch breaks down, is carried away and that area becomes again available for colonization. We don't really know the biofilm lifecycle behavior of our particular two species (at least I've not found it in the bacteriology texts I have or literature I've searched.) I do know that the fact that biofilms are now known to have a calcified 3-dimensional structure allowing for "tunnels" in some cases (for the oxygenated water and ammonia to flow through) is a hot area (or, I think so anyway, based on at least one paper that flashed by but I don't still have the ref.)

You are right, dwell time is an important parameter. I would think dwell time and permeability of the biomedia layer would need to work together. Its like capillaries in blood vessel structure, we want the mechanical bed design to slow down the flow, increasing the dwell time but for the capillaries to be of ideal size for the given autotrophic species and we want to guard against any design flaws or damaged media (eg. hole ripped in sponge) that would allow the water to bypass its surface contact with the bacteria. The good news, as I take it from old-timers is that in practice there's a lot of leeway. For instance, a young, clean bed of biomedia might be a little too permeable and a bed that's not been de-clogged in too long might be too constricted but there's a decent amount of middle ground where performance is sufficient.

~~waterdrop~~
ps. Yeah, I've thought a bit that it might be fun to move this out to a separate beginner thread just to have our own little one going as I think these type threads often get hidden off in the hardware section and not seen by the beginners...