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wpbullock
04-14-2009, 05:09 PM
I found a scrubbie supplier and was wondering if there were any rules of thumb for how many ft2 of biofiltration surface area you'd suggest for raising relatively low intensity fish (probably catfish, perch or bluegill or ....)

Per a website I found, scrubbies have an area of about 370 ft2/ft3 of material. My tank is about 1500 gallons and if I stock to end up with adult fish at a density of 1/2 lb per cubic foot (or about 1/15 lb per gallon) for a total of about 100 lb of adult fish to harvest, is there any rule of thumb to suggest how much surface area I need?

I have two ways I can go but sort of prefer the idea of choice 1 below:

1- I got an old hot tub pump with a high and low speed from my brother. The low speed uses about 300 watts of power and I was thinking it would be nice to just run that pump at about 2000 and wash the flow down over the scrubbies (maybe 4 ft3 of them?). I would make a distributor pan with holes in it to run down on the top of the scrubbies and make the bed of scrubbies 1 foot deep. It would be suspended above the tank and drain down into the tank. I was thinking about putting a box above the biofilter filled with shredded corrugated cardboard and use that as a filter for a slip-stream of the flow (most would go through the biofilter but some would go through the cardboard filter). I was thinking of putting red worms in the cardboard and letting them live off the fish waste and filter the water at the same time.

2- I also got a blower with the pump which was also from the hot tub. It blows a ridiculous amount of air and makes a huge geyser. It is also loud. Do you think I need the more air than I will get with the system of spraying down over the box of scrubbies? If so, I can set this up like the aquacube and submerge my scrubbie collection, maybe in a nominally 18" diameter piece of plastic drain pipe and blow a bunch of air in from the bottom. The only thing I don't like about this idea is that the blower is loud and may pull more power than the pump (not sure about that because there is no nameplate data on the blower).

Any thoughts about the pros and cons and if the pump and biofilter would be sufficient for oxygenating the water for 100 lbs of fish. By the way, I know it also matters how much I feed them each day as well.

Thanks,
Wes

badflash
04-15-2009, 08:12 PM
Scrubbies are great, but should not be used alone. Particulates need to be removed first. I use a bead filter on top of my scrubby filter. If you don't the scrubbies will load up and they are tough to clean. Been there.

Check
http://www.diyaquaponics.com/forum/showthread.php?22-Home-Brew-Filters for my home brew bead filter.

As to size, you need to figure that out by killing fish, sadly. I would start with about 10 gallons of scrubbies and see how it goes. If you see signs of stress, go bigger, but with your stocking density and the slow metabolism of your fish, it should be fine.

wpbullock
04-20-2009, 06:56 PM
I was doing some more reading trying to see what else I can learn about biofilters and, although this company has a vested interest in suggesting that structured packing is the best biofiltration solution for a simple trickle-type biofilter, I think they make some great arguments.

I am a chemical engineer by day and know that structured packing is the best packing to fill a distillation column with - it is consistent in terms of the available flow paths, resistant to plugging (definitely much better than gravel or even random dumped packing, and maximizes the liquid/vapor interface in a distillation column to improve the efficiency.

I was also happy to see that this looks like a fairly inexpensive way to purchase good quality surface area. I think I may aim this way instead of the scrubbies - but tomorrow is another day!

Here is a link.

http://www.biofilters.com/cmydocum.html

Wes

aquaarche
04-20-2009, 09:04 PM
are boifilters necessary if you are using rock medium in your growing bed? and is the ratio of gallons of water per fishtank the same per gallon grow bed 2 to 2 or 1 to 1

badflash
04-21-2009, 09:15 AM
If you are using a grow bed, it serves as the bio filter. You want twice as much grow bed as fish tank. Far less will do biofiltration, but it won't remove the nitrates and phosphates. The plants do that and you need that much space to have enough plants to do the job.

Stuctured packaging is what my Aquacube is made from. It works well. Be sure you pick a mesh size of at least 1/2" so it can't clog. The down side to that is it reduces the surface area. That is why I use the bead filter over the scrubbies. You can use a fine mesh bio filter like the scrubbies if you filter out the solids first.

wpbullock
04-21-2009, 04:23 PM
Aquaarche and BadFlash -

First Aquaarche. That link I provided in my post has a lot of good information that talks about surface area available with stone versus mesh versus dumped packing. I think stone works fine but doesn't have a lot of void space and so is prone to plugging with solids. It just means it will need to be cleaned out more often but is apparently how biofiltration was done for the last 100 years before more engineered materials became available.

The structured packing I was considering is, as you suggest, larger than 1/2". It actually has 3/4" openings. The stuff is not too bad on price and the thing I like about it is that I will sacrifice some surface area/volume ratio and end up with a larger biofilter but won't have to spend the money right away on a filter. Since my idea is to keep agitation down in the tank so that the solids tend to settle out and the I'll vacuum out the bottom periodically (we'll see how that goes) and send the solids to my conventional (dirt) grow beds. Because I don't intend to use air stones, at least at first, I won't be able to stock very intensively and hope that the trickling structured-packing biofilter will give me sufficient oxygenation to keep things happy. That link I posted a few posts up has a lot of the math associated with biofiltration area versus stocking and feeding density.

I also decided to take the advice of someone on this board and start with "cheap fish". I caught some bluegill out of my pond and tossed them in the tank two days ago and am now just circulating the water with my ex-hot-tub pump to get a bit of aeration. We also have a grain elevator in town where I can buy a bunch of stocker-sized catfish, etc. I might do that. I hate the idea of heating the tank all next winter (or anytime).

Wes

badflash
04-21-2009, 08:02 PM
Growbeds & greenhouses are the way to go. come winter or summer this will provide the biofiltration. The critter you chose will determine your temperature requirements. If the plants don't remove enough nitrates & phosphates, you'll need to do more water changes.

wpbullock
07-16-2009, 05:05 PM
Ernie, That is exactly what the aquacube is in my opinion. The structured packing is available from a guy in florida. I bought 12 ft3 for about $100. Go to biofilters.com to buy some if you want. He is pretty helpful.

Wes

jackalope
07-17-2009, 06:45 AM
wpbullock have you got a linky to the scrubbie supplier? I'd like to see their prices and what they have to offer ;)

Thanks :D

badflash
07-17-2009, 07:20 AM
Just remember with these systems, that the aquacube type filter won't remove particulates, but with growbeds it doesn't matter. If you use aerated scrubbies, they will need to be cleaned out periodically if you do not remove particulates before the water gets to them.

wpbullock
07-17-2009, 02:48 PM
I bought the kind with 40 ft2/ft3 on the advice of the guy that sells them. I think it depends on how clean your water will be (solids and crap). He told me that if I wasn't filtering my water (which I'm not) then I better stick with a pretty open structure. I also am trying to keep it simple and had an old hot tub pump so I elevated my 12 ft3 of stuff above the fish tank and bought also one of the big square pattern spray nozzles from the guy at the web site and am circulating about 40 gpm through it all the time. I think for the number of fish I have (only 100 in 1800 gallons) that this will hopefully give me enough oxygen and biofiltration area to keep up with the ammonia.

The verdict is still out on what I'm trying. I don't think the bacteria is fully established yet because my water is starting to smell sort of fishy. I am doing some major water changes right now to try to clear it up. The water goes on the stuff in the greenhouse. I also am not circulating my water through any gravel beds yet. If I was that would probably help. People on here are basically saying that the thing to do is circulate teh water through a grow bed and that will become the biofilter - no need for the structured packing. I just didn't set up that way - yet.

I do think that bubbling underneath the structured packing would probably do a better job of aeration than what I am doing (I would bet my paycheck on it) but I didn't have an aerator and I did have a pump.

I think what you are saying is right - just get a good sized aerator and some big air stones, submerge the blocks and then bubble air underneath. The air will lower the density of the combined water+air in the blocks and that will cause large amounts of water to be pulled up through the packing (blocks).

badflash
07-17-2009, 07:28 PM
Yes, that is how it works, but you MUST remove the solids. A gravel bed works great, but if you don't have that, you just have an aquarium. You need a filter to remove the solids.

wpbullock
07-19-2009, 04:20 AM
Badflash -

How do you respond to people who say that the gravel bed will end up collecting all those solids and then going anaerobic and potentially releasing H2S or, at a minimum, remaining aerobic and the decomposition of the solids would consume oxygen?

How do you clean you gravel bed?

Thanks,
Wes

badflash
07-19-2009, 08:03 AM
If you have a flood & drain system that bleeds it to the bottom, it never gets a chance to go anaerobic. That is why F&D's do so well. Put redworms in the beds and they wil break down the solids.

Eventually any bed will need cleaning, but not for several years.

wpbullock
07-19-2009, 04:51 PM
Thanks, Badflash. I may yet give it a try!

Wes

jackalope
07-19-2009, 06:17 PM
wpbullock have you got a linky to the scrubbie supplier? I'd like to see their prices and what they have to offer ;)

Thanks :D

linky please ;-)

badflash
07-19-2009, 08:32 PM
I watch the dollar stores. They have then all the time. Usually 5 for $1

wpbullock
07-20-2009, 03:46 PM
Jackalope -

This is the note the gent sent me...

Scrubbies are 3 x 3 x 1" or 9cu in
12 x 12 x 12 =1728 cu in divided by 9 = 192 per cu ft...
Depending on the Zip code you are located it runs less than 10.00 per 300
(I can get 10-300 pcs in a 17x13x13 box)
Just PM me with the amount you need and your zip code and I'll take it from there...
~Ben O aka zennzzo

And I found him on monsterfishkeepers.com

I don't have a link but do have an e-mail address. I hope it is ok to post it here but with some "encryption" using " at " for the @...

ixoye.truth" at "gmail.com

grimsteph
02-01-2011, 04:25 PM
Looks like 6 for a dollar on sale here: http://premiumfishfood.com/zen/filratio ... -scrubbies (http://premiumfishfood.com/zen/filration-products/bio-scrubbies)

I just bought a bunch of them. I need more biofiltration, and this looks like it will do the trick, and cheap too. My local dollar store had them in three packs for a buck, so even with shipping this is a much better deal.

aquaarche
03-23-2011, 07:28 PM
if any of you want to see my bio-filter I made go to http://chette.tripod.com/id40.html and you can see it and the materials I used to make it.

I will make a video on how to make a bio-filter out of materials I have. the plastic chemical makeup it the same as the ones sold online but are more expensive. this home made version works well. for the moment my video camera is in the shop.

Some one mentioned beads. Are those ceramic, glass, or plastic beads?

We have those bio-scrubbies here too. and they are cheaper if you buy them in bulk.

jay
12-18-2011, 03:21 PM
Hi, how do you keep the fish from going in the pump inlet? Are the scrubbies or bio balls just in a pipe with the water flowing around them on it's way to the plants? I have a hydroponics setup with 21 dutch buckets with tomatoes and cucumbers and an NFT system with Brussels sprouts, spinach, string beans,cabbage, and broccoli and I would like to add a fish tank with tilapia in it. Do I need a place in the tank with gravel for the fish to lay eggs in? Jay

urbanfarmer
12-18-2011, 04:21 PM
Hi, how do you keep the fish from going in the pump inlet? Are the scrubbies or bio balls just in a pipe with the water flowing around them on it's way to the plants? I have a hydroponics setup with 21 dutch buckets with tomatoes and cucumbers and an NFT system with Brussels sprouts, spinach, string beans,cabbage, and broccoli and I would like to add a fish tank with tilapia in it. Do I need a place in the tank with gravel for the fish to lay eggs in? Jay
Are you going to add the fish to the hydroponic solution or will you change out the water completely and then run off the fish waste as your plant nutrients?

Please read through Oliver's posts to get an idea on how everything works. It will answer most of the questions you have before you have them! :-)

jay
12-18-2011, 06:54 PM
I was going to build a new tank with a sloping bottom, I would hate to put the fish in all that fertilizer, than i would just run the water up to the NFT beds first until the fish get bigger. I read all 6 of Oliver's posts about setting up flood and drain beds- they were Great! I need to study everything 10 more times i think. Jay

keith_r
12-19-2011, 07:04 AM
you'll need to filter the water prior to it going to nft or you'll have all kinds of problems with clogging/root rot/solids buildup..

a "SLO" -soliids lifting overflow- can be set up to remove water from your tank to a sump, which then can be pumped up to growbeds.. or a filter of some kind.. if doing just nft..
i've seen plenty of systems with the pump in the ft though.. and it usually is not a problem.. if you have a pump with a pre-filter, i'd recommend removing it (the filter)

jay
12-19-2011, 04:42 PM
I really like Oliver's tower, I would like to incorporate bio balls into it, kind of like a skippy filter setup with the screen partway up holding about 5 gallons of balls or cut up floor scubber pads. I hope to have a drain at the bottom of the fish tank to drain off poo. jay