Green Water

[crsublette]

Higher flow rate is needed to keep dead organic matter from settling on the bacteria.

There ya go. One of the big reasons behind fluidized and tower bio-filters. Bah, i need to stop rambling, that really sums it up right there.

While the tiny bit of dead organic matter kills ammonia converting bacteria it's the perfect environment for harmful bacteria like Aeromonas.

That is a heterotrophic bacteria that may possibly create algae fighting allelochemicals, suggested by Mr. Meck

From what I understand, It'll take more than a thin layer of crud for the anaerobic bacteria to cause problems. Only takes .1~.5 mg/L dissolve O2 to prevent anaerobic bacteria from creating hydrogen sulfide. I can see how more than a thin layer of crud can be created easily in a static media filter and possibly even bogs.

 

[koiguy1969]

waterbug... i didnt answer my own question..neither did you. i basically asked ...if i put 1000 gph thru my filter and it maintains sufficient O2 to keep my bacterial colony alive, healthy and doing its job...why would i want a higher flow rate. when that higher flow rate is far more likely to keep particulates in suspension long enough to coat and clog the media. i still disagree with the higher flow rate for bio filtration in an upflow submerged media filter if sufficient O2 levels are maintained. now keep in mind. as i said, i use prefilters and send mechanically well cleaned water to my filter anyways.

 

[Waterbug]

Koiguy, I wasn't trying to answer your question. I'll try now.

if i put 1000 gph thru my filter and it maintains sufficient O2 to keep my bacterial colony alive, healthy and doing its job...why would i want a higher flow rate.

You wouldn't obviously.

when that higher flow rate is far more likely to keep particulates in suspension long enough to coat and clog the media.

Coating and clogging are different things. A river rock in very slow moving water can be coated with suspended matter that settles out. Clogging is a function matter size. Higher flow rate would not cause suspended matter to coat the rock, it would wash the rock clean. If instead of a rock surface we were talking about a drinking water filter a higher flow rate would cause it to clog faster.

i still disagree with the higher flow rate for bio filtration in an upflow submerged media filter if sufficient O2 levels are maintained. now keep in mind. as i said, i use prefilters and send mechanically well cleaned water to my filter anyways.

If the flow rate is high enough to keep suspended matter from settling obviously ammonia converting bacteria could live. As you lower the flow rate it would allow suspended matter to settle out and coat the media killing the ammonia converting bacteria.

 

[crsublette]

waterbug... i didnt answer my own question..neither did you. i basically asked ...if i put 1000 gph thru my filter and it maintains sufficient O2 to keep my bacterial colony alive, healthy and doing its job...why would i want a higher flow rate. when that higher flow rate is far more likely to keep particulates in suspension long enough to coat and clog the media. i still disagree with the higher flow rate for bio filtration in an upflow submerged media filter if sufficient O2 levels are maintained. now keep in mind. as i said, i use prefilters and send mechanically well cleaned water to my filter anyways.

Heh, think you're referring to me.

Waterbug was mentioning how crud is what hinders, or even kills, aerobic bacteria by the crud reducing O2 penetration to the bacteria. Higher flow rates reduces crud interference in trickle/shower towers and fluidized bio-filters.

Aerobic bacteria colonies will only grow according to volume of O2 availability since this is and KH are the main energy sources for their operation. Dissolve O2 and aerobic bacteria colonie size has a mutually exclusive relationship. Since Skippies is submerged media, then O2 penetration is signficantly reduced to the fact that water temperature dictates O2 saturations; this is unlike trickle/shower tower and wet/dry bio-filters where open O2 penetration constantly refreshing O2 saturation level as the aerobic bacteria consumes the O2.

Problem with Skippies is that a low flow rate is required since Skippies are also a settlement chamber. If flow becomes too high, then the crud will become lodged into the bacteria. Low flow rate is not the equivalent of a fines filters. There is still fine crud that will go up into the bacteria no matter how low the flow rate. Since the flow is so low, then this fine crud will never dislodge off the bacteria until the anaerobic bacteria do their job to remove the crud; this is the problem with Skippy filters. Skippy filters don't allow the fine crud to be washed off the beneficial bacteria due to the low flow rate; this is one reasons why Skippies must be drained since they are also a crud settlement chamber. This is why adding another mechanical filter to pre-filter the water prior to the Skippy helps big time with Skippy filters. To help clean the bacter, I can see how good powerful air diffusor can possibly fix this problem as long as channeling does not occur. Also, the Skippy's bio-media would have to be a good suficient height above the bottom to prevent the crud in the settlement chamber from getting into the bacteria.

Waterbug, I think ya are exaggerating a bit by saying how easy it is, such as just a micron coating of film, to choke off all O2, killing aerobic bacteria. If this were the case, then there would never be any beneficial bio-film, which probably contains aerobic bacteria, forming on the surface area of ponds; I mean the flow rate in a constrained container like a bio-filter is always going to be much higher than the water that passes by the surface area in a pond, unless TPRs are creating quite a substantial water current.

 

[Waterbug]

Waterbug, I think ya are exaggerating a bit by saying how easy it is, such as just a micron coating of film, to choke off all O2, killing aerobic bacteria. If this were the case, then there would never be any beneficial bio-film, which probably contains aerobic bacteria, forming on the surface area of ponds; I mean the flow rate in a constrained container like a bio-filter is always going to be much higher than the water that passes by the surface area in a pond, unless TPRs are creating quite a substantial water current.

I can understand why you think I'm exaggerating, the world of bacteria is very different from our world. Let's do some math to put it into perspective. The bacteria is about 1 micron, bio film about 50 microns tall, human hair about 100 microns. A layer of muck the thickness of a human hair would be the same to a bacteria as a 600 foot layer of muck would seem to us. Would I be exaggerating if I said it would be difficult for you to breathe under 600 feet of muck? And just like us as the particles lay on top of the bio film the fans are pressed flat by the muck.

Ah, but you're probably just messing with me. When will I learn?

 

[koiguy1969]

now with all that ...there hasnt been anything said here i didnt already know...now youve answered my question with your confirmation of what i said in the first place. a higher flow rate is not neccessarily a neccessity for proper biological filtration in an submerged media filter. and the addition of the flush valve (that a regular skippy doesnt have) has been more than adequate to keep my filter and media clean and doing its job. in both of my filters (basement wintering pond, and outdoor pond). even when i move media from one filter to the other and rinse out the filter chambers, theres just a real thin layer built up on the filter floor...

 

[crsublette]

Granyhuskr, I hope ya found your answer. I think ya need to describe how ya built your Skippy. I think Koiguy's diy designs in the forum are the best implemented Skippy approach to take and also making sure the water is pre-filtered well.

Granyhuskr, how did ya build your Skippy?


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Would I be exaggerating if I said it would be difficult for you to breathe under 600 feet of muck?

Nope, but I can't survive on 1 mg/L of O2 and hold my breath like bacteria. O2 is able to penetrate crud and depth is determined by the kind of crud. To remain aerobic, "bacteria only needs 1 mg/L or higher to stay alive." Aerobic bacteria only start dieing off once they are "O2 deficient starting at hour 4 and population declines significantly when passing the 24th hour." For denitrification, anaerobic bacteria actually start to grow when O2 is at around .5 mg/L and only start producing hydrogen sulfide (h2s) when 0 mg/L of O2 is available. A big deal for coral and reef hobbyists is to manage this process since nitrates is much more toxic to them.

Interesting thesis there by G.J.S. Thorn, that is explaining the diagram. He talks about how the biofilm helps to anchor the bacteria and the bacteria eventually grows its own biofilm to help attach more colonies so the bacteria does not remain free-floating in the water. He does not indicate this bio-film is killing the bacteria.

I am just pointing out that there is a degree of crud depth bacteria can tolerate until O2 penetration reduces below 1 mg/L and it would take more than a thick layer of bio-film to kill the bacteria.

a higher flow rate is not neccessarily a neccessity for proper biological filtration in a [static] submerged media filter.

Ya really are talking about static bio-filtration, not just submerged media filter. A high flow rate would be detrimental to a static submerged media filter without any type of pre-mechanical filtering.

Bead filters, Nexus bio-filters, and fluidized filtration are all submerged media filters except the media is always moving in during operation or during the backflush, not always static like a Skippy.

 

[Waterbug]

now with all that ...there hasnt been anything said here i didnt already know...now youve answered my question with your confirmation of what i said in the first place. a higher flow rate is not neccessarily a neccessity for proper biological filtration in an submerged media filter.

Correct. If you have an acceptable ammonia conversion rate for your pond you would already be at the high enough flow rate needed to keep media clean for your filter and pond. If you lowered the flow rate you could kill your bacteria colony. So yes, a higher flow rate is needed and you have it. You're trying to say a high flow rate isn't needed because your filter works and you don't consider whatever flow rate you have to be high. High and low are relative terms. If your flow rate is high enough to keep suspended particles from settling it's higher than what would cause particles to settle out. Butt simple. This isn't rocket science.

Or the other possibility is the ammonia converting bacteria you have don't live inside your filter at all and instead live only in the pump pipes, rocks in stream/falls, etc. If that provides enough space for the bacteria given your fish load and feeding amount you would never measure any ammonia or nitrite, and the filter would have nothing to do with it.

and the addition of the flush valve (that a regular skippy doesnt have) has been more than adequate to keep my filter and media clean and doing its job. in both of my filters (basement wintering pond, and outdoor pond). even when i move media from one filter to the other and rinse out the filter chambers, theres just a real thin layer built up on the filter floor...

There's the rub. Even a filter that has to be cleaned could have some clean spots where ammonia converting bacteria could grow like right around the inflow where the flow rate is high. But, in a filter that has to be flushed or cleaned there is certainly, no question at all, less space for ammonia converting bacteria and more space for harmful bacteria. This is why filters that wash media clean 24/7 are 10-30 times more efficient at ammonia and nitrite conversion, they have more available useful space for ammonia converting bacteria.

Years ago everyone talked endlessly about the surface area of media. More surface area = more ammonia converting bacteria. But people figured out pretty fast that huge surface area wasn't enough if the surface area collected muck because muck covered media couldn't hold the bacteria. Now days few knowledgeable pond keepers ever consider surface area at least specifically. They'll say they need to add another tier to the shower filter, or add another trickle tower. Indirectly they know they're talking about surface area, but gone are the days of saying things like adding 1,000 sq ft of media. The focus is much more on keeping media clean and keeping O2 levels up. Those are the limiting factors. 10 sq ft of media can out perform 1000 sq ft with the right filter.

And that is why Skippy is a poor bio filter.

 

[crsublette]

Hmmm ... I think it's all part of the same equation where water flow and O2 penetration aids the surface area ... mediaSurfArea * (h20Flow + o2Penetration) - biofilterFlushing = best bio-filter.

Ya don't really see people building shower towers or fluidized bed filters with the cheapest bio-media out there, without knowing they will eventually put better bio-media in there down the road. Aaahh, except for shower towers, since they're so huge and amount of space, it is just too cost prohibitive to put any fancy bio-media into them. Problem is k1, k2, alfagrog, Bacteria House, Bioflo 9, bioball chips and other medium can be quite expensive, but ya really don't need much of it since its surface area is being used so effectively. Side note, why is my fluid bed filter not stirring? ; i found it interesting.