Which way to go on a Bio-filter

[tandy]

Here is the story. I am putting together a 55gal tank in the house to start about 50 Tilapia and leave them in there untill they are 2-3". They may be moved out a little sooner all depends on how quick I get my 300gal tank set up in the barn. The issue is the bio-filter I been doing a lot of reading on them. The question is that I can not seem to find is, is there any advantage to a up flow verses a down flow. I have used a down flow in the past with no problems. This will be a new build so I can go either way. The only disadvantage that I can see on the up flow is you have to take all apart to clean the bottom where all the gunk will be coming in. On the old filter I had I used a course filter pads as a per filter where the water dumped on it. When they started to plug I could pull it out to clean. I am thinking that the filter will be 10-15 gallons in size. I don't think you can go to big. Looking for any input.

Thanks,
Tandy

[badflash]

You need to explain to me what you mean. I prefer using drilled tanks with a sump underneath with the bios filter in it. I use a bead filter on top of a bio filter loaded with scrubbie pads. I have a submersible pump in the sump that moves the water back up to the tank. It overflows out of the tank, down a drain line, back to the sump.

You can check it out here:
Home Brew Bead Filter (http://www.diyaquaponics.com/forum/showthread.php?109-Home-Brew-Bead-Filter)

[tandy]

What I mean by up-flow is when the water is brought in under the filter media and the water flow is up and out a outlet at the top of your tank holding the media. I have seen these designed from 5gal pails to 100gal stock tanks.

Tandy

[Brier]

Should make little difference on a biofilter, unless you are also using it for mechanical filtration, in which case upflow will allow for a drain at the bottom for solids removal. If you use upflow, I would recommend adding an airstone in the bottom of the filter to agitate solids when you drain it. During normal use the airflow would be turned off.

[davidstcldfl]

Hi Tandy, I built a filter for my 50 gal that's in the house. It's 2 parts.....there are 2 tubs, one sitting on top of the other.

The water from the fish tank flows into the 1st (top one), which is where (most of) the solids settle. The top one, has a stand pipe that penetrates the top of the bottom tub.

The water flows to the bottom of the lower tub and flows 'up'. I have a small pump that sits on top of the bio-material. Of course, it pumps the water back to the fish tank.

I just siphon off the solids every day (or two) from the top tub...and I disassemble and rinse the whole thing out, about every 2 weeks.

I keep duckweed in the top tub....helps with the nutes. Plus, it's a handy treat to toss to the breeders.

I'll try to post a few pictures tomorrow. I need to clean it out anyway.

[rfeiller]

up-flow filters do not pack down and load up like down-flow filters, for nitrification they are far superior because of the free spaces between the media from the up lift of the water. you will find that more of the particulates settle on top of the media then below it.

for ammonia scrubbers we would make a vessel that would have a large source of air to push up through the media vastly improving the nitrification. the best filtration for nitrifcation of course is not a particulate filter (mechanical filter) and that is what a downflow is a mechanical filter; it compacts the medium and restricts the nitrification. a good example of a nitrifying filter media is bio-balls vast exposure to oxygen.

mechanical filters almost immediately start having areas of anerobic activity because the downflow filter has started choking out the oxygen loaded fresh water. of course for denitrification to remove nitrates you need anerobic bacteria, but those filters are extremely tricky.
hope this hasn't been too confusing

rich

[urbanfarmer]

I'm not too sure the up or down flow is particularly relevant when speaking in general whereas the exact design of your filter is. If you could be more specific as to the materials, dimensions, etc. that you plan to use are, I am sure we could give much more specific advice...

[JCO]

You have another problem. I don't know how big your tilapia are now but they grow fast and 50 2" to 3" tilapia in a 55 gal tank is going to be very crowed and there is going to be a serious problem if you don't have enough filtration. Once their gills get damaged from ammonia and nitrites, they will start dying and there will be nothing you can do to save them at that stage. Don't forget, they are little pigs and will want you to feed them continuously and if you do, that will only worsen matters.

A large wet/dry filter with bio-balls and a high volume pump would be best. Check http://craigslist.com I have found it to be a most useful tool for parts. :mrgreen:

[Brier]

If you want a real bio filter, forget bioballs, and other commonly used media. Look at RBC's ( rotating biological contactor) The downside is difficulty to build. Then look at fluidized bed sand filters. Downside is they are finicky. Lastly look at moving bed filters using kaldnes media. Down side, and the only one, is that the media itself is rather expensive. IMO these are the best filters overall, at least for a larger system. A small system, like a large fish tank, and you cannot beat a sand filter.
Any system I ever use over 300 gallons will hence forth, and forever more use a moving bed. Simply the best. Biofilter, degassing column, and aerator, wrapped into one with virtually zero maintenance.

[rfeiller]

It's a given you can not start with a new filter that has not been cycled for that high bioload in time to save your fish. There are many different filter configurations out there and most if the better ones will cost a lot more then your 55gal tank. If you are on a budget which most of us are, black lava and a makeshift container connected to an air pump and water pump will get you started. I had 60 - 30 gal tanks on a central "wet dry concept filter of 50 gal capacity. But it has to cycle. Supplemented with small individual sponge filters

[Brier]

It's a given you can not start with a new filter that has not been cycled for that high bioload in time to save your fish. There are many different filter configurations out there and most if the better ones will cost a lot more then your 55gal tank. If you are on a budget which most of us are, black lava and a makeshift container connected to an air pump and water pump will get you started. I had 60 - 30 gal tanks on a central "wet dry concept filter of 50 gal capacity. But it has to cycle. Supplemented with small individual sponge filters

Glad you mentioned sponge filters. They are very effective for the price. They really amaze me, and when needed you can easily move them from tank to tank. Can also move them to a brand new tank to use as an isolation or hospital tank. http://business.accesscomm.ca/ultimatesponge/ These are very cheap, and very effective. 4 of them will filter a reasonably stocked 55 gallon tank with no problem.

[rfeiller]

Absolutely, a seasoned sponge filter can be squeezed over another filter. great jump starter!

[tandy]

Thanks for all the input on the filter. what I ended up building is a up-flow fliter. I used a 10gal tube from Lowes that is about 13" dia. I built a stand for the botton with egg crate on top with 5 layers of 1" thick filter mat that I had left over from when I had rainbow Trout. The pump I used is a 550gph with a filter on it. The Tilapia may be here by the end of this week or next week. I agree if the Tilapia get to 3-4" I will have to split the tank. Looking forward to raising fish again.

Here is a picture of my current syatem with lettuce growing ( if it works ). I started these by seed 10-2-2010 in rockwool then transplanted them to the floating raft on 10-22-2010. To give you a idea on size the holes are spaced 5" apart.

http://i1217.photobucket.com/albums/dd399/01tandy/Hydroponicsystem.jpg[/IMG
[img]http://i1217.photobucket.com/albums/dd399/01tandy/Lettuce1.jpg]



What I have growing is from left to right Red Fire, Buttercrunch, Slobot, Ithaca, Green Towers, Summertime.

I was having problems with PH as my water out of the well is 8.2. I was using Citric Acid to lower the PH but I had to use a lot of it. What happen was it started to grow a slim in the water. I did a complete water change and went to Muriatic Acid to lower PH. Muriatic works so much better. In just a couple of days things looks a lot better. For nutrient's I am using Ionic Grow at 25% rate. As you can see some of the lower leaves are dieing but since the water change the lettuce is greener and the bottom leaves look better. Look foward to any and all input.

Tandy