Backyard Aquaponics
A place to discuss aquaponics

I have a question for you, Joel.

Andrew and I are gearing up to buy your book - but were tossing up between the book and the kit. How long does it take for the bacteria to establish itself if we don't buy the full kit which includes bacteria? We have a creek here and were planning to use gravel from the creek.

cheers

The bacteria does help things along by speeding up the time it takes for a system to become in balance. Typically without adding beneficial bacteria to a system, the system will have bad algae blooms for about 3 months. This means three months of 'pea soup' before the bacteria can naturaly establish itself and grow enough of a population to balance the system.

By inoculating the system with beneficial bacteria when first starting the system, you might typically wait about 3 weeks before the bacteria population builds up enough to balance the system.

However, if the gravel you use is from a stream, and the gravel has remained wet, there will already be some beneficial bacteria here.. Though also the posibility of transfering problems into your system as well along the lines of parasites, but then chances are you will get these anyway with fish stock etc....

Joel,

I've got a neighbour who has about 20 large fishtanks under his house, where he breeds and grows (ornamental) fish for trading.

Can I grab some of his filter contents and drop this in the growbeds once I've got the system up and running? There should be plenty of bacteria in the filter media to get them growing in the gravelbed one would think.

Karel

Yep, that would help establish beneficial bacteria into your system Karel...

Thanx for that Joel.

Joel,
Do you test your water parameters often?

I'd be really interested in where your nitrate level sits at if you have tested it.

Also have you ever drained or partially drained any of your tanks and refilled with fresh water?

I realise that the system is meant to be topped up with freshwater due to evaporation and plant uptake, but i'm curious about possible mineral build up through evaporation and subsequent top ups as although plants require many minerals excesses can be as devistating as deficiencies.

you'd be surprised at the amount of things in our tap water

I think i'll rig up the guttering to the 1000Lt tank once i have the perch in a new home. i'll use the stored rain water as top up.

What are your thoughts / comments

Steve

Steve,
No, I don't test my water very often at all, the only thing I have ever tested is ph, and I only test it once every 6 months or so. The main reason I test the ph is if the water quality doesn't look so good. Often minor blooms of algae seems to be the byproduct of a change in ph, so when I see an increase in algae I check the ph and fix accordingly...

I do change out some of my water on occasion, and it's not wasted as it's pumped out onto the garden, bu8t tap water is all I have to top the tanks up.. Though I have never noticed any ill effect on the fish or plants from tap water..

The "if it aint broke, don't fix it" approach.

I like it

I tend to over think / analyse thing too much sometimes........but i like to know "whats going on inside"

A nitrate test kit costs about $27 from an aquarium shop and lasts about 90 tests, they are used to indicate when a water change is needed due to the nutrient buildup from the bacteria as aquariums are really only half an aquaponics system.

They would be a good indicator of plant VS fish ratio's. IE if your reading is between 0 and 10mg/L then it tells you that there are tomany plants.

I'll post some figures once my system is up and running. I like the ability to make changes to things and have hard figures to judge their effect.

The aim for aquarium fish is to keep it as close to 0 mg/L as possible.

I used to keep mine at about 40Mg/L when i had aquarium plants under light, and i used to have to CULL my plants monthly as they would fill the tank!

The kits usually read upto about 160mg/L but its hard to read the chart past about 80mg/L

Steve

Joel,

I'm curious, does your PH shift up or down over time?

I'm fairly sure the nitrification process naturally shifts water PH down.

I used to be forever buffering my PH in my aquarium up. I used to run it like an aquaponics system except i was using water plants.

I never used to do many water changes as the aquatic plants took care of the nutrient problem, but as i said the PH would always shift down towards the 6.3 to 6.0 mark where the nitrification bacteria work REALLY SLOWLY.

Since then i put a couple of handfulls of sea shells in and noticed the ph stayed much more stable around the 7.0 mark.

I've since loosely crushed some shells and placed then in a nylon bag 10cm x 10cm and placed them in my filter so they are in the water flow.

It was the last time i had to buffer my PH upwards

I think the way it works is in acidic water the calcium carbonate from the shells is "eaten" by the acid hence neutralising it.

And its MUCH better than using plain old backing soda to raise the PH as too much of this will cause problems for the plants due to the sodium.

Just thought i'd share what i had found

Steve

Strangely enough I have had my systems move both ways Steve. There was a stage a year or so ago where my systems became alkaline with a ph of around 8, or just over. But then more recently I have had the more typical lowering of the ph, where it was at around 6.

Shells are a great way to buffer your system as your suggesting, and it's a good idea if you add some limestone into the gravel growbeds when your building the system, this works as a reasonable buffer, and one that works long term without any thought.

Yep, as the ph goes down the bacteria slow down and you end up with algal bloom problems, and theres nothing worse than having pea soup water....

Hi Guys
Intresting re limestone as I was planning to use some in my gravel beds for this reason. Would I have to be carefull how much I used?

Steve you said "if your reading is between 0 and 10mg/L then it tells you that there are to many plants." Dont the plants use up the nitrates so if the level goes up wouldn't you increase the amount of plants. I am suspecting I migh missunderstand this aspect of the process.

By the way, how long do we have to ask for tyhe vial of bacteria??? We (the school) bought the full pack a few weeks ago and I am almost ready for the bacteria now... should I have fish in befor the bacteria, or after introducing the bacteria?

Dunno MT, i'd just be guessing

The way that i'd do it is to add it in stages after your system is full steam ahead and has been running with fish for at least a month. that way you can see how it affects PH and you won't have a really high ph when there is risk of elevated ammonia.

RE: nitrates yes, if it goes up i'd add more plants, but IMO 10mg/L is not high. if it is at 100mg/L and still rising then yeh, plant more, but once again these figures are "in the air". Posted more for a theory purpose, don'
t get too caught up with nitrates as they are the least dangerous to fish of any of the levels, and the higher they are the more the plants grow.

I didn't mean that you would pull out plants, probably more like drop in some more fish, as the plants are doing fine at ntrate removal

AM, I generally add the bacteria when there are fish just into the system, the bacteria will need some ammonia to survive on and if you have no fish in your system then it's going to cause the bacteria to die off a bit unless your supplimenting... I would suggest that we plan it so that I send your bacteria at about the same time your fish are arriving. A few days either side won't matter but you will have to put the bacteria into your system pretty much as soon as you get it rather than leave it in the bottle for too long..

Am, just to avoid confustion, i started typing my reply before you posted the question about bacteria. I was replying to the LIMESTONE question