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floppingflamingos

probably the worst wet dry you may ever see...

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Dwell time is far more important than fast flow rates in most filtration. However, looking at this design it is very closed and deep. Active nitrifying bacteria will strip oxygen extremely rapidly leaving low or nil disolved oxygen levels (DO) which will greatly hinder the biological filtration capacity and you are returning this low DO water directly to your tank .... so in this case the high water turnover is a good thing.

There are a lot of inefficiencies here which could be easily corrected if you would like to bounce some ideas around. The general concept of overhead filters is pretty efficient though!

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I saw with my own eyes something very similar. Instead of a big plastic bottle they used an Australia Post grey plastic sorting box and had it resting on top of the tank's glass lids.

It kinda worked like one of the purpose built Top Filters, just not as neat: http://www.aquariumproducts.com.au/catalogue_products.php?prodID=3346&catID=83 (no not a plug for AOA, just couldn't find a quick photo of a Top Filter)

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hey homies, brisil your filter design is what made me start this and the fact i dont need an overflow. ive been looking around the place and found this stuff can you see this working?

kjhh001.jpg

i was gonna put bio balls in the container tray thingy. but i think that there will be spots with no flow through the media this way. and i dont want to make it like a sump so i was thinking if i connected the bucket to the tray i could put the bioballs in the bucket as well as the tray. like the paint picture in my other post. or could i get rid of the bucket and put a hole in the tray somewhere where i could have bioballs exposed to air and submerged.. thanks for you help so far guys, but im still in need of some more because im pretty clueless when it comes to anaerobic and aerobic bacteria, Chears.

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i found a design i like, i figured the last design was to much of a hassle with the sides exposed and such well here it is,

filter003.jpg

filter004.jpg

equipment needed: lunch box, styrofoam box with lid*, and a tray and i've managed to find a piece of of foam that fits the tray so i can do the sump thingy, of course i still have to put a hole in the bottom of the styro box :D

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lol check it fools

Fab013.jpg

Fab014.jpg

:oops:

nice isnt it, ill get some bioballs for it when i can.......i got bored

Sorry, I get quite busy sometimes and even now I dont have a lot of time for clear explanations. I can see you have already changed your design but looking at the first version, some areas for improvement are:

1) Your water piping and bio-chamber are clear. It wont take very long for algae or sludge to accumulate. Algae in bio-chamber will create lots of clogging resulting in channeling and is quite difficult to clean.

2) There is no overflow. You have quite a lot of water going through the chamber and the media is quite fine. It wont take much for a flood to occur.

3) As mentioned briefly, this chamber is very closed. Even if the top were open or air were forced in with the water (venturi on pump) , the mechanics of concurrent circulation are extremely inefficient when compared to counter current systems. I am talking about heat and gaseous exchange/circulation. Example if air and water entered the top together, there would only be limited exchange of gas and heat until equilibrium were reached. At best this will only be 50% of available heat/oxygen/carbon dioxide. Whereas if air were forced in from the bottom against the flow of water (counter current circulation) the exchange can continue till resources are totally exhausted. I dont want to get to technical so please google for this principle/concept or if people wish, I can explain this in more detail later.

Anyway, to make a long story short, adding a fan at the top wont make much difference whether it is pushing or pulling but adding a fan at the bottom will. Alternatively, enclose the bottom outlet to create some ponding water and install an airstone inside. With ponding, the air cant escape out the bottom and will be forced up through the media column. Counter current is HUGELY more efficent than concurrent circulation. I wish I had time to make up a diagram for this.

4) Choice of bio-media is questionable. Good surface area but far too fine for the high flow rates you have. I suggest either some mechanical prefilter (sock?) or a looser weave material. Active bacteria will die a natural population cycle creating a lot of detritus and slough at the bottom of bio-media areas. Also with exessive surface area, the amount of active bacterium is still limited by the food available. This means a filter ten times as big as another will not be any more efficient. It is the young actively growing population stage bacteria which does all the work. A larger filter has more buffer for expansion but even an large filter will take a while to grow new bacteria (become active) and can easily have ammonia and nitrite spikes if you overstock rapidly.

5) As mentioned, you are returning severely oxygen depleted water directly to your main tank. Ideally counter current aeration or a small re-gassing stage/chamber or even a small cascade (waterfall) step before would help here.

I am sure there are other smaller nitpicks but as you have already changed design, I dont want to flog a dead horse. I am mostly posting for other posters and discussion purposes. Your general concept is solid. I am sure some people will disagree with some of my explanations as there are many different facets of filtration.

In summary: If you wanted to be very lazy, I suggest you add an emergency overflow and go with open weave media. ie Have NO mechanical filtration stage on this unit. Purely bio-filtration and zero maintenance. I will commment on some of your later versions later but the foam box one has disaster all over it!!

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WOW! 8O thanks for the great reply! scrapped the foam box. im thinking i may ust get a hole heap of buckets stack em tightly and drill holes in the bottom of each. you were right it did overflow! but dont worry that happened during the night. so i didnt notice till the morning...... :x

so 3-4 buckets stacked on top of eachother

with alot coarser material in each layer.

like cintered glass, bioballs, ceramic noodles and such?

but because the buckets are gonna be stacked wont there be little oxygen getting into it? im sorry if im a bit dependant on your info. but its helping greatly!

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You could use two (or more) small stackable containers on top of each other. that fit on your cross brace. divide one or both so there is an over flow. just a thought.

tony

Add a pic it"s a bit rough

untitledtt.jpg

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yeh i really like the diagram you did, its given me some really good ideas and i saw that today aswell. i mite go the flowerpot route unless i can find some skinier stackable containers. one thing i was thinking i could use as biomedia is that lava rock stuff i think you use in barbecues anybody ever use this stuff?

I also have had lots of trouble finding eggcrate, do you think the mesh out of the bottom of those plastic bread trays will be inert?

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people use gutter guard instead of the eggcrate, i used acrylic and drilled a heap of holes in it(gotta love the machines at work that do it for you ;) )

there are heaps of things you can use if you cant find it, try find something that is clear/white or food grade, so it doesnt leech chemicals/colours and cause dramas down the track

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Whats the update with this project? All the ideas posted so far are solid including your original water bottle idea. Some just need a few more tweaks than others.

The most efficient cheapest media I have used is prawn trawler netting. Its nylon, lightweight and free if you ask the net repairers for the damaged sections they cut out/dump when repairing. You can pull it out of 200L barrels (bio towers) one handed for cleaning and can be packed as tightly or loosely as your density requirements change.

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ive still been experimenting.

filterbetter002.jpg

filterbetter006.jpg

Drip plate put that cotton stuff onto that.

filterbetter004.jpg

This compartment is to be filled with bioballs

filterbetter007.jpg

and one of the tank :esmile:

mytanks016.jpg

that ring is the top of that spring water bottle to keep the cotton stuff from leaving the filter, cotton will be removed when i get my hands on some bioballs. should i cut holes in the side of the bucket where the bioball compartment is, above the bioball line? for gas exchange.

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