Backyard Aquaponics
A place to discuss aquaponics

Wondering how long bacteria survive. How often do they need water flow to maintain the level of oxygen and nutrient to keep them going? Minutes hours days??
Any help appreciated.

hay mac,

I have no idea, but someone will, wait for Steve and co. Welcome to another Adelaide aquaponist!

Welcome mac. Not sure on the frequency of water flow. But the levels required to keep up your DO levels is enough Steve should be able to explain it.

If the media to which the bacteria are attached dries out, they die.

The bacteria colonise the media and then build up proportionate to the nutrients that are there to feed them.

so even with a small flow (but nutrient rich) there will be a plethora of bacteria?

But I suppose it also depends on if your whole bed (in regards to depth) is getting wet. Maybe that's one of the advantages of flood and drain.

Sure would be and advantage... Getting an eaven spread in a continious sflow (like mine) is a lot more difficult/challenging...

Once I have my mark 2 system up and running I will try my hand at flood and drain (continious flow just seems far less complicated to me right now!)

I have two 60 litre trickling bio-filters hooked up to my system and the rate of flow through each is about four or five litres a minute. They are probably able to sustain a flow of up to 20 litres per minute.

The keys to effective bio-filtration include continuous effluent flow, plenty of airspace and lots of surface area upon which to grow the bacteria.

I use the bio-filters to breed up beneficial bacteria and to condition media for use in satellite pots and other plant growing systems.

I've used clay aggregate and oyster shells as media but there are other options including rocks (that's what they use in large sewage treatment plants) or bio-balls (a commercially-available media). Plastic is a good surface upon which to grow bacteria so short sections of small bore plastic pipe will work also.

When you load a bio-filter, it's a good idea to place the media into the drum rather than just tip it in. The goal is to get the water to take the longest possible trip through the bio-filter.....ensuring that as much of the media is splashed by the nutrient-rich water as possible.

To ensure even distribution throughout the bio-filter, I made up a circular 'distributor' out of poly hose and a Tee joiner. I drilled a series of holes around the distributor so that the water from the pump squirts from the hose ensuring that the media is kept wet.

Macbass,

Gee, sound like everyone thinks i have the answers! Usually i do, but i've found it very hard to find any definative data on if and how long bacteria can survive without oxygen or ammonia.

What i do kow has already been mentioned. The bacteria CAN NOT withstand drying out, their cell walls do not allow for it and they can not form spores. So if your media or biofilter drys out then the bacs will be DEAD

I will try again to find out if and how long nitrifying bacteria can survive with out oxygen and nutrients.

This also makes an important point for if say one of your pipe joins brakes and you lose alot of your water, not only may you lose all your fish (depending on how long it takes you to find out about the problem), you may also lose your bacteria. That could really set some systems back. New fish you can get relatively quickly, but new bacteria still takes 2-3 weeks to setup shop.

I am curious at what pH range they can be killed, rather than just not working.

I have had gravel sitting in the back of my ute (under cover) for over a week now and I scratched off the top layer to a depth of about 25mm (1") and the gravel was still damp, I would think that any bacteria would last for some time before drying out, especially in a growbed which would have a lot of moisture in the base.

I can't see it as a problem if the system can be brought on line within a reasonable period
Fix the problem, throw in some goldies if necessary to keep the system going then restock, restocking I see as the main problem.