mm live gravel/sand in freshwater.. the debate

[macmain]

we all know about our friendly bacteria on all items in our tanks but check this out ..
what's your opinions.. it talks about gravel mainly.. but sand sub-strait (like fluidized sand filters) could be a massive benefit
more surface area

http://www.athiel.com/lib/lg-fw.html

thanks all

[OinKY]

Already do it to an extent. Just use a deep substrate and only vacuum off the top,occasional probe to check for pockets of gas...which I haven't had any hydrogen sulfide (yet).

Safe to say anybody with a substrate over 2" is doing it,to an extent,whether they know it or not. Seldom does anyone ever turn over their entire substrate every week.

[macmain]

my thoughts exactly, i have 2 geos that are like bulldozers. hence the name eartheaters.
i have never done a vac of my sand substrait. in 2 years.
i used too then i got the geos.. 1 min id have mess on the sand the next it would all be gone . covered not eaten.
obviously it breaks down.
so i do no vacs, water params are spot on and crystal clear,

[KDodds]

BTDT, for many, many years with ARLC. Before graduating to planted tanks, my tanks of choice were all (FW at least), Cichlid tanks, mostly ARLC. All of them have had 3-6" beds of natural gravels/sands for years. Caveat: an unstirred, perfectly still bed (like many people keep their planteds) with little flow over, and no sand stirrers CAN become a problem (just had this discussion on another forum, where I gracefully bowed out due to persistent and willful lack of understanding). Where small grained substrates are used and ALLOWED TO COMPACT (IOW, neglected due to ignorance), you can have H2S buildups that can be harmful. In KNOWLEDGABLY used tanks, this is ridiculously easy to avoid. Still, you probably do NOT want to use potting soil as the base for a planted tank and then cover it to a full depth of 6" with the "cap", and then NOT add "sand" stirrers/sifters and neglect to allow for SOME flow through. IOW, Deep Subtrate systems work in FW and SW and are NOT dangerous PROVIDED you're not doing it completely wrong. Of course, it doesn't help (see willful lack of understanding above) that everyone already "knows" that anaerobic zones are deadly, that H2S will accumulate to lethal levels, etc. Oh, you'll get some blackening where the anoxic biofiltration is occurring. Absolutely. You'll also get slow release of the H2S gas in bubbles from the bed, periodically. If you DON'T get those bubbles, something's wrong, something's compacted/impacted and preventing natural gas exchange through the layers. Potting soil will EASILY do this. Larger grained gravels, not really.

In a planted tank, though, we're you're trying NOT to disturb root systems, things can get a little tricky. Biofilms can cement grains together, so if there's no movement of the substrate at all, no flow through at all, yeah, bad scenario to think about DSBing. Otherwise, it works very well. It's too bad there's such a paucity of infaunal organisms for the FW "DSB". Hence, I relied on fish.

[macmain]

BTDT, for many, many years with ARLC. Before graduating to planted tanks, my tanks of choice were all (FW at least), Cichlid tanks, mostly ARLC. All of them have had 3-6" beds of natural gravels/sands for years. Caveat: an unstirred, perfectly still bed (like many people keep their planteds) with little flow over, and no sand stirrers CAN become a problem (just had this discussion on another forum, where I gracefully bowed out due to persistent and willful lack of understanding). Where small grained substrates are used and ALLOWED TO COMPACT (IOW, neglected due to ignorance), you can have H2S buildups that can be harmful. In KNOWLEDGABLY used tanks, this is ridiculously easy to avoid. Still, you probably do NOT want to use potting soil as the base for a planted tank and then cover it to a full depth of 6" with the "cap", and then NOT add "sand" stirrers/sifters and neglect to allow for SOME flow through. IOW, Deep Subtrate systems work in FW and SW and are NOT dangerous PROVIDED you're not doing it completely wrong. Of course, it doesn't help (see willful lack of understanding above) that everyone already "knows" that anaerobic zones are deadly, that H2S will accumulate to lethal levels, etc. Oh, you'll get some blackening where the anoxic biofiltration is occurring. Absolutely. You'll also get slow release of the H2S gas in bubbles from the bed, periodically. If you DON'T get those bubbles, something's wrong, something's compacted/impacted and preventing natural gas exchange through the layers. Potting soil will EASILY do this. Larger grained gravels, not really.

In a planted tank, though, we're you're trying NOT to disturb root systems, things can get a little tricky. Biofilms can cement grains together, so if there's no movement of the substrate at all, no flow through at all, yeah, bad scenario to think about DSBing. Otherwise, it works very well. It's too bad there's such a paucity of infaunal organisms for the FW "DSB". Hence, I relied on fish.

hi thanks,
dsb's are dangerous. hence why i dont use one or the "said" most ultimate form of filtration FSB,incase of power outage.incase Good bacteria perish. but, my post is mainly about general substrate 1.5-2". none planted. ( sorry if the article pushed you that way) and the artical mainly talks about gravel. so i am looking for ppl that religiously vac there sand and say maybe leave it a little longer than usual. n see what happens.. keep up with water tests, and monitor..
honestly i do not ever vac my sand now. maybe the sand sifters breaking up detrius and because i have such a large flow rate may be part of it.. but i dont vac and do all water changes in another room.


ta

[KDodds]

Actually, DSBs are NOT even remotely dangerous unless you're not doing any homework or maintenance. There are WAY too many knowledgable people actually utilizing them (instead of talking about why they don't use them) successfully for that to ever be considered true. They're about as dangerous as ozonizers. Do it blatantly wrong and YOU can kill your tank. The tool is not dangerous, but the aquarist can be.

I'm not exactly sure what you mean by "live gravel" or "live sand" then. If there is no benthic infauana, the substrate is not "live". Plain old gravel and/or sand in a standard FW set-up will never reach a state where it can be called "live" by any real standard. Bacterial films will form on the grains, and the more surface area the better. But to get it to do something, anything more that it's doing, with or without vacuuming, is pretty much moot. The most you can do is siphon off bacteria and detritus. Since there are no detritus feeders, there's nothing to starve out, and leaving it in will tend to produce a nutrient sink (good for plants, bad if you don't want algae), and possibly harmful, polluted conditions. BUT, you can accumulate a LOT of mulm/detritus before that ever happens (we're talking measurable in cm over the top of the substrate). So, siphoning mulm is mostly aesthetic (within or on top of the substrate), even when speaking about algae. After all, algae isn't really a "problem", it's life seeking balance. No nutrients, no algae. Algae isn't unhealthy (and can in fact make for a healthier system if allowed to grow), but it is unsightly to most. Now, if you're siphoning mulm, it's not really going to effect bacteria much (if at all). Most tanks are stocked to a point where bacterial colonies with the gravel or sand bed will never starve and will, depending on localized nutrient availabilty, always exist at loaded concentrations. Established tanks, IOW, will not change in biological filtration capacity simply because you've vacuumed the gravel. Truly live substrates, however, are a completely different story.

[OinKY]

On the topic of truely "live" substrate...
"Live" is relative,and as long as there are aerobic/anaerobic bacteria and other heterotrophic organisms present it is basically "live". Get deep enough into the heterotrophic types and there are organisms that handle every possible waste product produced in day to day aquarium life (including Hydrogen sulfide)...as long as you don't mess with them.
As long as conditions are right,if an organism is introduced to a favorable environment it will flourish and do its thing.Best example I can think of is personal experience...the Native Darter Tank I use to run.
Set up with local fish from local streams with decor straight from the streams with no quarantine or prep.Safe to say I introduced every good/bad thing that was present. With a 3" gravel bed and spinning at 30X turnover it never got gravel vacuumed and testing showed it only needed a minor water change ever couple of weeks.
Now the good (actually really bad) part... total power loss for 3 weeks in dead of winter.No filters,no water changes,no heat (tank froze over)....no problems. Oxygen-loving fish swimming merrily beneath the ice over a stagnant gravel bed while I lost every other tank and its occupants to the cold (Native US Darters are a tough lot in the cold).Once thawed out,with minor losses (cannibalism has its perks),testing showed the nitrates weren't bad (20) and 0 ammonia/nitrites.
So zero gas exchange at the surface and no filtering....but still no ammonia/nitrites or other supposed "problems" from a stagnant substrate...what happened? Natural organic processes. The aerobic organisms got fed,which fed the anaerobic organisms,which fed the other heterotrophic organisms,which keep the other organisms going.
Long story,but simply put if you keep the anaerobic conditions anaerobic by not messing with a deep substrate,and have the proper other heterotrophs in place,then the only problems you will have will simply be aesthetics.The amount of stirring done to a substrate by organisms (fish,snails,crustaceans,etc.) that are part of an environment is negligible compared to an aquarist with a gravel vac and good intentions.Of course,with a substrate under 2.5" I would always recommend a good gravel vacuum weekly simply because they aren't deep enough to have proper anaerobic activity.

[KDodds]

Yup on the gravel vac... where "live" is concerned, I tend to agree.

Larger grain sizes don't require as much (if any) stirring or turning, so larger infauna are not that important. However, when you start getting into sands, especially oolithic substrates, things get a little different. Where gravel may have almost no anaerobic activity at 2-2½", oolithic sand already has a substantial anerobic zone. The processes that occur can means pH can vary from water column pH at the surface of the bed down to -.4 at a depth of 2½" (tested). At this point, some substrates are no longer inert and serve to buffer (melt into solution) a bit. This, combined with biofilm, can serv to cement grains together and form a crust. If this happens, it is possible that the upper and lower zones can become sequestered. This can lead to a DSB "crash". For this reason, in terms of defining the term "live", most advocates of "live sand" do not consider the bagged bacteria stuff as even remotely live. The substrate requires a SLOW and steady movement through it which can only most easily be accomplished by larger benthic organisms or fish.

The turnover, as OinKY has said, needs to be a slow, steady, natural process. The aquarist meddling in affairs introduces oxygen into the anoxic layers, killing off much of what as there. And worse, aerobic organisms are pushed down into the lower layers where they'll also die off. This is one of the primary reasons why FW only aquarists sometimes have trouble believing how a "more difficuly" marine system can be readily kept WITHOUT a filter of any shelf or homemade kind. An aquarist I know from another board calls it "voodoo filtration". Simple fact of the matter is that, if you have the diversity, if you do it properly and stock reasonably, you don't need a "filter" any more than a small lake, pond, or even coral reef, does. Life IS a filter as long as you're not constantly trying to sterilize or partially sterilize your tank. This would also include ANY treatment used to discourage any form of life (i.e. algacides).

One of my biggest peeves in the hobby is "algae problem". Algae in tanks is NOT a problem, it is a symptom of something else that may (or may not) be a problem for the pivotal occupants (usually fish). Algae is life seeking balance, life creating its own filter because no other means of filtration is allowed to occur that would lower the available nutrients feeding the algae. With deep substrates, you will almost always find less algae as nutrients that would fuel the algae are used up by the bed instead, never allowing algae to gain a reasonable foothold.

MOST experienced marine aquarists do not go with SSB (shallow sand bed) systems because of this. The SSB is not near as efficient. If the stocking load is not incredibly light, the SSB will not be able to keep up and algae and cyano maintenance can become a neverending chore. This is why most marine tanks are either fairly deep (3-6") or BB (bare bottomed). And I can confirm that any time I've tried a sand bed of 2-3" or less, cyano has required routine maintenance and (which I abhor doing in SW) regular water changes. Maybe not at first, but eventually.

On the FW end, my 135 has recently sat for about a year with 0 maintenance other than top off and twice daily feeding, no filter cleaning, no water changes, nothing. Did it look a little rough around the edges? Well, that would be an understatement, I'm still trying to get some mulm away from the Val roots. But it's not overgrown with algae, and the (pretty ancient for their species) original occupants remained healthy. That kind of neglect can not be supported by a thin layer of gravel and a filter. The substrate in question here is EcoComplete to a depth of between 3 and 4". As OinKY said, it's bound to be chock full of microbes, but I wouldn't call it "live", more like "biologically active". Yeah, that's hair splitting. But when you're already accustomed to the terms "Live Rock" and "Live Sand" meaning substrates chock full of benthic organisms visible to the naked eye (most of which consume detritus so that you don't get the mulmy conditions I did), you kind of want to make the distinction. Microbes will never exist in large enough populations in a tank to keep detritus from accumulating, long term. "Live" substrates, in the sense that I am using it, can exist for decades without ever accumulating any detritus at all.

[OinKY]

I'm going to try my hand at my version of "live" (by KDodds definition) freshwater substrate soon.
I'm working up my list of benthics (most native locals),but my main concern is going to be their reproductive rate...that or stocking fish that won't eat them...to keep them from "peaking" and then dying off.
Should be interesting.

[KDodds]

Yeah, IF you can collect, that's probably the only way to go... native. You can kind of improvise with tropical tanks a little more now... this or that shrimp and/or crayfish, maybe some MTS and Physa spp. snails. But something like bristleworms? Terebellids? Nope. And they're the most effective stirrers and detritus feeders, really. And, many of the inverts that you CAN get won't be able to reproduce or sustain populations unless you're VERY careful aboutt he fish you stock. A lot of THAT has to do with FW fish, in general, being more opportunistic in their diet, as species and as individuals, than SW fish. That, and you don't usually have all of the "unhuntable" nooks and crannies of Live Rock, no pod piles, no refugia, etc. And, that's not likely to change any time soon, I don't think. Most LFSs aren''t going to bother with MTS or Physa, and definitely not with worms and live beds from wild sites. The money and market just aren't there. Of course, you can still get an impossible (for most) to feed "freshwater pipefish" that are doomed to die. It's all about the market.

FWIW, they ARE FW fish, but they only get to 6", which means a VERY small snout. Some say they'll eat bloodworms, but I don't see how. Our Dragonface Pipes (marine) are just about the same size and shape and take Daphnia or Cyclopeze. However, most (WC) Syngnathids will only take live food.

[OinKY]

I've answered questions on "mysterious mosquitoes" in tanks a few times. Amazing how midges look like mosquitoes...and bloodworms are midge larvae. Also detritus feeders to boot. So you could actually seed with live bloodworms (of course only adults reproduce) and get that effect...if you don't mind adults hanging around the tank lights.Only heavy sifters are going to weed them out...or burrowers (like loaches)...but that's more natural stirring going on.

[KDodds]

LOL, nah, I prefer "gnat free" tanks.

[callen]

Nice thread! Very interesting and informative.

[macmain]

wow. loads of info, although i have to admit some has gone over my head.

so in lamens terms, what are we saying.. sorry, im sure there are many ppl that have read the comments and feel the same.
from what i have read it doesn't matter how deep the substrate is. it will harbour beneficial bacteria.
hence my op of live gravel/sand.. surly beneficial bacteria in my substrate makes it "Live"

thanks to all who has contributed so far..

[OinKY]

Has been a good thread.Most don't think about the beneficial bacteria everywhere else in their aquarium.

from what i have read it doesn't matter how deep the substrate is. it will harbour beneficial bacteria.

This is a true statement...but the depth determines what types of beneficial bacteria are present and in what numbers. The types determine what biological conversions are done and what by-products are produced.
The deeper the bed,the more types of bacteria present,the more by-products produced and consumed...it's a circle.

Much like your love of Matrix. Does a fine job on nitrate conversion...but do you know why it does it?
And not because of surface area.....