Filtration rates, flow, and other questions

We are getting there but not quite.

Yes, the bigger hose will cause the sprinkler to spray higher, but the reason for this is not because of back pressure or anything to do with the sprinkler, it has to do with the diameter of the hose.

Let is recap: the flow rate and the pressure from the tap is the same for the thin or the thick hose. However from the formula F = pA, we can see that the pressure is the same, yet the area is much greater, in this case four times (pi x r2) so F, the force is four times greater and therefore the sprinkler will spray a lot higher. This is a physics principle and very important in pumping anything through pipes. Air pipes for example, if you use narrow air pumps you find the force will drop and you cannot pump a airlift filter in deep water, and if you use a pump for water it is always better to use a thicker pipe. The same applies to the filter, if you have a bigger surface area (in other words, my argument for a single compartment with a larger surface area), the force through the filter is greater than through a 4 x smaller compartment filter, it is simply the physical rule which will determine this.

Food for thought hey?

Kind regards,

Dirk

 

mmmmm, i cant wait to build my single chamber sump.

Prof can you maybe post a pic of your sump and its layers and spray bars?

 

OK Guys,

This is a filter design, which is basically a separate tank/sump which you can use next to an aquarium of which the side dimensions are 500 mm high and 600 mm wide which is typically what is required for a discus tank. The same design with changed measurements can be used for any sump, it is the principle of the one chamber design which I am trying to indicate that is important. Please note that the left chamber as shown in the upper sketch, which would be at the back if you looked at it in the bottom sketch, is closed at the bottom. This is purposely like this so that you can establish a syphon from your aquarium into the back chamber which would not be broken if you emptied the tank slightly and if you did any maintenance on the filter. Please note also that a heater can be placed in the chamber on the right in the first chamber as indicated and because the powerhead intake is above the heater level, it will never be able to pump the heater dry so that the heater cannot be broken by water loss caused by the powerhead pumping out all the water.

I also put an airstone into the chamber above the sponge or filter wool so that the water going over the filter is well oxygenated.

Kind regards,

Dirk

 

And now I have gone to all this trouble to post my filter and now you have all died? No comment?

 

Thanks for sharing Prof

So I am still looking at HMF vs all the other methods - and if we ignore mechanical filtration - then the sump looks like a big horizontal HMF with added media behind it. My understanding is that the HMF is most active in first few cm of the media, that is why you can get away with a 3-5 cm filter (5 cm being mechanically stronger I suppose) - I have also seen discussions that state that stacking multiple HMFs has little overall improvement - yet this is exactly what your big sump is - or is the gravel the real secret? If I took your design and did a stacking top -> bottom - filter floss, 10 ppi, 30 ppi and fill the rest with 45 ppi I suppose it would be the same? Maybe less maintenance with gravel / sporax?

Later F

 

Hi Dirk,

I have taken note of your design for when I want to move over to sump. It does definitely go against the "norm" but I do see how it can work better. (Your hosepipe analogy sold me). There was only one thing that I didn't see. In SA power cuts are a part of our lives... does this set up accommodate excess water in the event of a power failure? If I look at your picture, I don't think the "return chamber" would allow for this excess, because the water is coming from the bottom... so the only other "idea" I had to modify it would be to have the return chamber slightly lower than a 4th chamber to the right... allowing excess water to simply overflow into this... BUT then when the power turns back on, there's a chance that the pump will then run dry, because you sitting with excess water in a chamber you can't get to... Hmmm...

 

Hi Dirk,

I have taken note of your design for when I want to move over to sump. It does definitely go against the "norm" but I do see how it can work better. (Your hosepipe analogy sold me). There was only one thing that I didn't see. In SA power cuts are a part of our lives... does this set up accommodate excess water in the event of a power failure? If I look at your picture, I don't think the "return chamber" would allow for this excess, because the water is coming from the bottom... so the only other "idea" I had to modify it would be to have the return chamber slightly lower than a 4th chamber to the right... allowing excess water to simply overflow into this... BUT then when the power turns back on, there's a chance that the pump will then run dry, because you sitting with excess water in a chamber you can't get to... Hmmm...

 

Hi Ferdie,

I agree with you that this looks like a HMF. I also agree that the first couple of cms would be the most active. Crucial for the functioning of the filter is that oxygen rich water should go through the filter. In an aquarium, in which you have a HMF, it is only the oxygen that is dissolved in the aquarium water that can get to the microbes on the filter in order to allow them to do the biological filtration. In the chamber type filter as I have shown, you can put an airstone above the filter material and aerate strongly, which means that the water going over the filter is containing the maximum oxygen possible and I view this to be very important.

With regard to your comment about whether one could use sponge instead of gravel or Siporax, I can only quote the literature which states that the biological filtration bacteria colonize a solid medium better than sponge or filter wool.

Another aspect that is definitely valid is that the flow rate through a series of sponges will be poorer than through an initial layer of sponge and then siporax or gravel, and flow rate is important here, and this has to do with oxygen penetration again.

Ashley, I have shown a design for a filter that can be used next to your aquarium and of which the top water level would be the same as in the aquarium. If you used this filter design for a sump, then you would have to accommodate for the volume of the overflow and you would have the make the filter deeper or wider to accommodate for the water. However, the basic principle of what I wanted to illustrate.

Finally, I wanted to add that in my discus system, I run this type of filter a little differently in that I have a mechanical filter which removes all the floaties from the water, and then I have this type of filter filled only with gravel of which the diameter of the pebbles varies from 1 to 2 cm. This filter is positioned above a sump and it has two outlets, two pipes which empty the filter back into a large sump. Water is jetted onto the gravel and the gravel is not underwater, but the filter is actually a trickle filter. Before the water goes over the filter it is also heavily aerated. In combination this is the most efficient filter that I have. It also has a huge advantage is that when we have a power failure all the water runs out of it and allows oxygen to enter, but it keeps moist. My sump is large enough to hold the water until the power comes back on, but in this way the bacteria performing the biological filtration are not damaged during power failures. If you have a power fail and the filter remains full of water that is not moving the bacteria would use up the oxygen and if starved of oxygen for too long, then the bacteria would die, so power fails remain a problem.

Kind regards,

Dirk

 

Zoom, you wont have much excess water if you drill a small hole in the return line (pipe from pump to tank). You can drill a hole just above or just underneath the water surface in the tank, this acts like a syphon break and you wont have any problems with water running back to the sump...

 

Makes sense ... oxygen starvation and max oxygen for the bacteria - noted thanks.
"biological filtration bacteria colonize a solid medium better than sponge or filter wool" This I did not know as a fact, but seems plausible.
"I have a mechanical filter which removes all the floaties from the water" - yeap that is the only thing holding me back from doing HMF's on most of my tanks - I will probably still need a separate mechanical filter - maybe HOB's?

Thanks for the feedback - it is more food for thought.

Later Ferdie

 

@Dirk Bellstedt Okay, so after reading all of this I'm still interested to see a photo of your filtration setup. And how do you deal with the death of the bacteria in your sump in the case of a power failure? Or is it only anaerobic bacteria at that level and aerobic bacteria in the trickle filter level?

 

Hallo all,

Being a beginner is so frustrating. You read all you can and think you understand, just to go and make a bolls up on the simplest thing. I read here ceramic rings is the best bio material. I could not find any and in the LPS I found a bag of promising looking objects. Bought it and put it in my filter. I do not remember if it was before or after reading about ceramic rings. The other day, after reading, I went and read the packaging of my 'bio-media'. Turned out to be substrate! (Biggish funny looking stones) (Yea, laugh at the stupidity, at the time I did not even know what substrate means!) So off I go and buy some ceramic rings I found in another LPS. I just did a filter change and when opening the ceramic rings, I found to my surprise it is porous, not smooth like I expected. Now I see you guys did mention that it is porous and therefore better. But on the packaging I read that it is meant as a mechanical filter medium and no mention is made of bio filtering. I have wasted such a long time in getting bacteria going and want to get it right now. My levels is spiking and I am doing water changes to try and lower it. Antichlor is being used at an alarming rate! To my wallet that is.

I do not have a massive bore in my filter either, so it is critical that I use the best media possible. Can we discuss this please. I have an outside canister filter, claiming to do 1200l/h, but I measured the throughput by timing the amount of time it pumps 1lt. The result is 360 l/h. Tank size 90 lt, so the rate is 4 times an hour. If it was not for the small bore, 32x37x45, it would have been OK. Maybe it is still too fast?

Also, you can stack 4 layers of different media. The water flow is from the bottom to the top. What would the sequence of media be and what is the best 4 to use? At the moment I have the filter wool first(being the bottom), then charcoal with wool on top, then my ceramic rings and then wool again.

Thanks for this forum. Without it I would never even have thought about these things.

Regards
Tom

 

@Tom.K I am sure the prof will jump in - but some quick observations. I had a look at you album - seems like you have some "new" plants (still in pots ?) and non aquatic plants ( if the photos are of the same tank) - some of this could be contributing more than one thinks.

Re your questions. - The ceramic stuff - can be both mechanical and biological at the same time. I learned allot from TASA and looking into what I want as the perfect filter - my current thought of how this works is as follows (if I am missing something here guys please jump in and correct.)

Water from tank ->
Mechanical filtration (sponge or bio-media) - biological filtration ( bio-media or sponge) - water treatment (removal or adding of something specific) - water polishing (fine pored filter media - sponge, compact material etc.) water to tank ->

Look at a media like EHEIM bioMECH or equivalent that ensures excellent mechanical filtration, has dirt-trapping ability, allows for faster decomposition of toxins via optimum pore structure etc .. Then some sponge - then maybe charcoal if you are trying to fix something (controversial at the best of times) - more sponge topped with filter wool.

I have learned that doing filter wool to early in the filtration process (irrelevant if you have a canister or not) clogs up way to fast and then your flow gets reduced .


Later Ferdie

 

@f-fish

Thanks Ferdie. I will look for EHEIM bioMECH. Do we have a sponsor stocking it? By the way, when I said 'filter wool', most of the time I meant a spongy material resembling filter wool. I have filter wool just as the last medium.

Hope you are right about prof. Will like to hear from him as well, and others.

 

That bio substrate stuff would most likely still make for a pretty good biological media in a canister filter, so don't worry too much about it. I think the main reason people use filter floss on the first section of filter is because it's cheap, and it's easy to rinse or replace. So it's a good mechanical filtration media that will prevent the rest of your filter getting clogged up with gunk.

 

I've heard from a little birdie that Sera Siporax (Eheim also has an equivalent) is the best way to go. Looks like bio rings, but made from sintered glass it has a huge filter capability. I chucked about 2kgs in my sump just to be safe ;-)

 

Hi guys

Just a couple of things. The ceramic rings you buy at most LFS are designed to be mechanical media, although they may harbour some nitrifying bacteria, because all mechanical media will eventually become a home for such bacteria. Now if you have a sump you can toss in a whole lot of these rings and it should work pretty well. However, you could also toss in some gravel (substrate) and get just about the same result.

Sera Siporax is the best biological media for a cannister filter. It looks like ceramic rings, and it is way more expensive than the no-name brand stuff you buy at LFS, but also quite different.

If the water flow in the cannister is from the bottom to the top, then the order of media should be:
Mechanical -> Biological -> Chemical
Most often the last media is a "water polisher", such as fine floss which will trap small particles and make the water nice and clear.

If you bought this cannister as new, then the box/manual should tell you the order of the media and it won't be much different from what I said above. The order above follows the water flow direction, and that is how it should be.

In my cannister I have 5 compartments, and I use:
Ceramic rings -> coarse sponge -> plastic bio balls -> Sera Siporax -> fine filter floss
In the last compartment I may add Zeolite, activated carbon, etc, depending if I need any chemical filtration. I normally don't add anything like that unless I have a specific need.

I intend to replace the bio balls with more Siporax in the near future, but for now it is working fine.

 

Even better than Seachem Matrix ?

 

Siporax was originally made by an old glass company called Schott, they still make laboratory glassware of which I use a lot in my lab. Years ago when one bought Siporax it was made by this company and this company only. Then there seemed to be one crib after the next most of which were not of the same quality, and I think that the reason for this was that the patent did not go through everywhere. Eventually, I understand, Siporax brand was sold to Sera and that is where we are now.

I know nothing about the Seachem product, I have never seen or heard of it. They have a very heavy marketing angle in which they try to convince you that what they sell is always better. I am yet to be convinced. What I can say is that I see their products are sold at very high prices.

Kind regards,

Dirk

 

@Altum

Please can you post the conversation we had regarding the Matrix?

For those of you who are unaware, Altum use to import the seachem stuff for SA, and his knowledge on the matrix will give us the correct answers. I personally purchased some Matrix yesterday for when I set up my new tank. Dirk, I think R60.00 Matrix per 100litres is not too bad... especially if it really does what it claims. It works out to be 250ml of Matrix for 100litres of water... therefore on my tank, I would only need 750ml. If you consider how little that is, you have excess space in your filters for other stuff because it takes less space. Or you can fit more in. But I'll leave Altum to explain.