gelf
Wed Apr 11, 2007, 09:42 AM
Hey all,
Those that know me would know I'm a mad man for cultivating and feeding live foods to my Blue-eyes and Rainbows.
Also, these fish have tiny fry.
The problem: Commercial filters all rely on a combination of biological, chemical, and physical filtration. The pysical filter was my problem, be it a sponge, gravel, or some other form of porous medium. This physical filter removes anything solid that passes through the filter, be it food particles, live foods, or even eggs and fry.
The solution: Develop a filter that had no physical filter component, where the water could gently flow over a large surface area without passing through a sponge or other filter medium.
My initial idea came from a presentation at an ANGFA NSW meeting by Leo of a biological filter developed by an ANGFA Qld member. I took this idea and had a play till I cam up with what I consider a better filter that is effective and simple to make.
My filter:
What you'll need:
* Rectangular PVC downpipe (choose diameter per filtration need)
* Enough straws to pack in each end (I like the tough McD straws)
* 20mm diameter round PVC riser
* ¾” Grommet
* Ice cream container lid, or similar
* 4x 290mm long zip ties
* An air supply to run the filter
Using 105x55mm rectangular downpipe packed with 230 McD straws this filter has an effective filter area of ~150,000mm2
Construction:
Choose downpipe diameter to match your filtration need
You’ll need 46cm of rectangular PVC downpipe.
Drill a 25mm diameter in the centre of the downpipe as shown in the attachments
I find 105x55mm rectangular downpipe more than adequate for 2’ tanks
Choose a straw no longer than 210mm, and preferably with tough sides to prevent collapse
I find the McD straws are a good length, and are tough
You will need quite a few, so buy a bulk lot or ask nicely. Do not steal
With 105x55mm downpipe I need 230 McD straws per filter
Pack the straws into each end of the downpipe
Pack slowly and jiggle as you pack to ensure the straws pack properly. You will need to force straws in to ensure the entire lot is packed tight
Push the straws flush and use something through the drilled hole to push any straws back that have come in too far
Cut your 20mm diameter round PVC 10mm longer than the desired water depth of your tank. This is your riser
Using an angle grinder, grind 3 wide grooves at the base of the riser
Insert the grommet and then push the riser into position
The filter when active will tend to float. It will need a base with a weight.
I use an ice cream container lid held in place with zip ties. I then use a potted aquatic plant to hold the filter down
The amount of air blowing through the air stone will determine the quantity of water that passes through the filter per hour. Choose a slow flow rate to maximise biological filtration. Choose a fast flow rate with the assistance of an air curtain to assist in maintaining suspended food particles
I use a length of solid air tube with an air stone on one end, and an air flow tap heat-glued on the other
This is just slotted down the riser and connected to an air line.
And there ya go,
You have a biological filter that won't remove food particles, kill fry, or damage micro-fauna.
Cheers
Tony
Those that know me would know I'm a mad man for cultivating and feeding live foods to my Blue-eyes and Rainbows.
Also, these fish have tiny fry.
The problem: Commercial filters all rely on a combination of biological, chemical, and physical filtration. The pysical filter was my problem, be it a sponge, gravel, or some other form of porous medium. This physical filter removes anything solid that passes through the filter, be it food particles, live foods, or even eggs and fry.
The solution: Develop a filter that had no physical filter component, where the water could gently flow over a large surface area without passing through a sponge or other filter medium.
My initial idea came from a presentation at an ANGFA NSW meeting by Leo of a biological filter developed by an ANGFA Qld member. I took this idea and had a play till I cam up with what I consider a better filter that is effective and simple to make.
My filter:
What you'll need:
* Rectangular PVC downpipe (choose diameter per filtration need)
* Enough straws to pack in each end (I like the tough McD straws)
* 20mm diameter round PVC riser
* ¾” Grommet
* Ice cream container lid, or similar
* 4x 290mm long zip ties
* An air supply to run the filter
Using 105x55mm rectangular downpipe packed with 230 McD straws this filter has an effective filter area of ~150,000mm2
Construction:
Choose downpipe diameter to match your filtration need
You’ll need 46cm of rectangular PVC downpipe.
Drill a 25mm diameter in the centre of the downpipe as shown in the attachments
I find 105x55mm rectangular downpipe more than adequate for 2’ tanks
Choose a straw no longer than 210mm, and preferably with tough sides to prevent collapse
I find the McD straws are a good length, and are tough
You will need quite a few, so buy a bulk lot or ask nicely. Do not steal
With 105x55mm downpipe I need 230 McD straws per filter
Pack the straws into each end of the downpipe
Pack slowly and jiggle as you pack to ensure the straws pack properly. You will need to force straws in to ensure the entire lot is packed tight
Push the straws flush and use something through the drilled hole to push any straws back that have come in too far
Cut your 20mm diameter round PVC 10mm longer than the desired water depth of your tank. This is your riser
Using an angle grinder, grind 3 wide grooves at the base of the riser
Insert the grommet and then push the riser into position
The filter when active will tend to float. It will need a base with a weight.
I use an ice cream container lid held in place with zip ties. I then use a potted aquatic plant to hold the filter down
The amount of air blowing through the air stone will determine the quantity of water that passes through the filter per hour. Choose a slow flow rate to maximise biological filtration. Choose a fast flow rate with the assistance of an air curtain to assist in maintaining suspended food particles
I use a length of solid air tube with an air stone on one end, and an air flow tap heat-glued on the other
This is just slotted down the riser and connected to an air line.
And there ya go,
You have a biological filter that won't remove food particles, kill fry, or damage micro-fauna.
Cheers
Tony