Backyard Aquaponics
A place to discuss aquaponics

I was also thinking of using shadecloth stuffed into a small length of PVC as a biofilter. It's lightweight, cheep (I've got a whole stack of it in the shed), has a large surface area, and if it ever gets clogged up I can remove it easily and either hose it off or replace it.

If you are going to go for that sort of thing, also consider bird netting.

When you hose off the bio-filter media, you also hose off the substrate which accommodates the bacteria.

This may not be a problem if all you are looking to do is strainer out solids - in which case you do not have a bio-filter but a filter or strainer.

A biological filter, is by definition, a device which encourages the colonisation of beneficial bacteria.

That's what I mean, a mechanical filter not a biofilter (the biofilter will be seperate) although over time it will serve the same purpose to an extent.

I'd think it would be a problem when you took it out and cleaned it as you would loose some of your bacteria, and there by the balance of your system would be off, never stable just all up and down. I wouldn't do it unless your just experimenting.

mmm...I seem to remember a post of Steve0's saying the more diverse the system the better it is. More balanced more bio mass the more bio mass the more balanced and so on.
C1

In my mind, once a system is balanced you have a set number of fish, a set number of plants and a set amount of bacteria.
To remain in balance
1. If you harvest a plant you must plant another.
2. If you harvest a fish you must add another.
3. If you reduce the amount of bacteria the whole system goes amiss as it must now begin the cycling process all over.
So if you were to take a balance supporting colony of bacteria out of the system by washing your filter or dumping one grow bed I'd think you would see ammonia spikes as the bacteria attempted to compensate for the loss. With that one would be chasing your tail every time you washed the netting or what have you. Don't you think that would be the case?

I agree with GF. You end up with the amount of bacteria in your system that is needed to deal with the fish waste. When fish waste reduces, bacteria reduces and vice versa. I guess one unknown (for me at least) is how quickly the bacteria levels can change to compensate for fluctuations in waste etc. For example, if I stop feeding for a few days while away on holidays, can I go straight back into my normal feeding regime when I return - or should I work up to it over a few days?

VB, nothing concrete here, but i'd say that if you droppped feeding for a few days or even longer and then brought it back up again, you would be fine......... The bac.s reproduce to the level where there is no more ammonia to covert. I think this is primarily due to the nitrification process being so energy consuming, that there is very little left for reproduction. so thats the mechanism that comes into play for the colony size.

Now if you LOWERED feeding (ammonia) i'm sure that they would survive happily at their current colony size until you brought it back.

Otherwise all the bacteria in the bottles wouldn't be very viable

I have never had any problem with loosing bacteria on bio media if you gently rinse it in the tank/pond water. If you use a hose or something the chlorine in the water will damage your precious bacteria as well

here are some pics of the system

CG, more pictures please and a bit of description.

cool

a next one

the pump