Straw filter design - need feedback.

Ronald Lao

Background: Recently found out that I may have a problem with imbalance in my nitrification vs fish food intake. So I need to make more bio-filter. I currently have 1 200 gallon "moving bed" bio-filter that is underutilized because it is only filled with 15% bio-balls. Cost is a problem since bio-balls retail for about $0.20 USD per piece. Estimated cost even at wholesale prices would force me to shell out approximately $180 USD.

I thought I could make a bio-filter media from cheaper materials and here's what I am proposing. I need your feedback for Thumbs up or Thumb suck. Please reply!

Step 1: Start with semi rigid drinking straws. I found some bending straws in the supermarket for around $0.40 per pack of 100 pcs. Alternately you can just collect used ones if you have a source.

Step 2: Cut the straws into sizes of about 10 to 12mm.

Step 3: fill in a net bag. Tadah! Homemade biofilter media!

mattyoga

I think they will work, though not with the SSA of a bio ball, and they may eventually clog and be hard to clean.

Charlie

Great cost effective solution.

cookie

My EFFIN word... THAT BRILLIANT!! man the things ppl come up with.. excellent choice it should work perfectly. mind you it may take a while to grow the new set of bacteria on that media.

Yavimaya

Great work ronald.

joblow

Sleepe

Any idea what they are made of?

Depending on the bio balls I have found them a PITA for moving bed filters as most lock together.

Stuart Chignell

Ronald Lao wrote:

Background: Recently found out that I may have a problem with imbalance in my nitrification vs fish food intake. So I need to make more bio-filter.

While the idea of using straws may be a good one, I question the accuracy of this original statement. Any AP system that doesn't have enough surface area to work as a bio-filter will also not have enough plants to use the NO3 produced by Bio-filtration. Therefore in a system where you need extra bio-filtration rather than adding a dedicated bio-filter simply add more plants.

If you don't you will have to either do water changes or add AQ di-nitrification components.

Ronald Lao

Sleepe wrote:

Any idea what they are made of?

Depending on the bio balls I have found them a PITA for moving bed filters as most lock together.

That's my problem as well, they lock together so bad idea to use in a supposed moving bio filter. He he. We learn from mistakes...

So moving on I just changed the name from moving bio filter to my bio filtration unit.

cookie

@Stuart although that statement is true.. plants or more importantly plant roots aren't really reliable Biofilers for the reason that the plant must mature for the roots to grow out bigger.. so what happens is for some reason he cannot get anything to grow? then is nitrification problem will not have been address.. I always believe to have a separate filter for biological conversion and just leave the plants to uptake nutrients alone.. alot simpler that way

Stuart Chignell

I'd agree that you shouldn't rely on roots alone but there should be enough surface area with the roots to provide more than enough nitrification.

The issue is that there is likely something else is wrong.

coachchris

Ronald, creative idea. now you helped me rename by filter a Bio fitration filter. My mbbf doesn't move either.

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Ronald Lao

@coachris

Wow! I envy your bubble sprays... My single high cap air stone is such a far cry from that! (Hides the picture) ;P

Ronald Lao

Stuart Chignell wrote:

While the idea of using straws may be a good one, I question the accuracy of this original statement. Any AP system that doesn't have enough surface area to work as a bio-filter will also not have enough plants to use the NO3 produced by Bio-filtration. Therefore in a system where you need extra bio-filtration rather than adding a dedicated bio-filter simply add more plants.

If you don't you will have to either do water changes or add AQ di-nitrification components.

Hi Stuart, There was another longish discussion in another forum about my problem, diagnosis and findings. To make the long story short, I didn't want any of the fishes I bought to die, so although my design called for 80 fishes to a tank, I put all 191 pieces into the tank. Hence my problem. :mrgreen:

Ronald Lao

UPDATE: Alternate straw filter design

One thing about the straw filter is that they have a positive buoyancy. Nothing like that of a Styrofoam but still enough to float above the waterline if you put them in a net bag. I am sharing an alternative solution for it.

Problem: straw filter will sometimes float above the water line due to positive buoyancy.

Solution: I mixed some pumice stone with the plastic straw. From what I read, Pumice is PH neutral and has a porous surface which should also be good for bacteria to grow in.

NEUTRAL BUOYANCY: As you can see I put in enough Pumice stone to make the whole bag have a neutral buoyancy so it can freely move with the water currents inside the barrel.

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