Backyard Aquaponics
A place to discuss aquaponics

muz, how long do you estimate the coco peat to last before degrading to a point where it will need to be replaced?

Muzz - is the potassium source organic. Wonderring about its affect on the fish etc.

Asitis, I feel the bacteria did take a little longer to colonise the coco peat, although I do not have any hard evidence of that really. In my next grow bed with coco peat I will have a couple more distribution pipes to better share out the fish waste through the coco peat.....perhaps that will help.

Les, I tested nitrates again today...still zero. Yesterday I doubled the amount of food to the fish, but it is possibly too early as yet to see a difference I guess...the bacteria colony will have to upsize itself etc, so I suppose that will take some time. I am finding it hard to resist the temptation to go and get some more fish !!!!

Steve, the coco peat is not showing any signs of breakdown at all as yet. One thing though, when I remove a lettuce there is a large root mass that is hard to separate the coco peat from, so over time there will be a loss of mass because of that kind of thing. I have a load more coco peat coming so I will just put a bit of new stuff on top.

Murray - increase in nitrates will certainly not be overnight. My system took weeks to register nitrates again the time that I let them drop to zero while on a week away. This was with 30 perch all of decent size. Mind you I could only feed once a day.

It is not that you are not producing any nitrates now, it is that the plants are taking what you produce as soon as it becomes available. As your fish start to produce more, the plants will also tak this straight away. This means that until your fish start producing more nitrate than the plants will take, your nitrate level will not start to rise. Problem is that this also means that once it starts to rise, it will continue to do so to levels that are too high, unless you increase the number of plants in the system or the amount that the plants are taking. This will probably happen naturally as the plants will get bigger, fruit etc - thereby using more nitrate.

I don't think you will have any issue with the bacteria - with the amount of medium you have in your 3 beds, they will increase their population quickly enough to cope with the extra ammonia and nitrite straight away - if not, you will see this because your ammonia and/or nitrite tests will show some in the system.

Regarding getting extra fish - if you really want to, go ahead, but I wouldn't get an extra hundred. You gotta think about whether your system will support them long term. In your situation I would be temped to temporarilly remove 1 or 2 grow-beds from the main system and temporarilly support the plant growth via an alternate nutrient source (not thrive) - though I guess it would be easier to buy extra fish and deal with any oversupply when that becomes a problem. By then you may be ready to add more beds to the system or start a second system.

Out of interest, how often a day are you now feeding and do the fish eat much. Those latest seq fish fingerlings are certainly tiddlers. I guess it will be a while before they are eating much. Do your big perch feed heavilly?

VB, The potash/potassium is "Searls Liquid Potash" 250ml bottle for $6.50 which will make up 250 ltrs of spray. I am reading directly off the bottle, does not say if it is organic or not, so I guess it is not, however, I felt that it would not worry the fish as it is sprayed on the leaves of the cucumber plants.
No visible difference as yet to the plants.
I really appreciate the test kit as I am getting the picture now that perhaps my plants have been starving badly. I always had the plan to have a few too many plants in order to safeguard the fish, but I think I have been overdoing it. Trouble is I want another 3 grow beds up and running this summer, so as soon as the picture is clear I will be off to the hatchery to get me some more fish I reckon.
My dear wife has taken a real liking to fresh ready lettuce and tomatoes smothered in basil and parsley, so I can't let up now...... I am under instruction to grow more vegetables.
Muzza.

Oops - must have been posting at the same time. More beds sounds great. Off to the hatchery then you should go :-)

VB, The last lot of fish were so small but they are growing very well. As you say, they would not produce much in the way of food for the plants. The big fish get most of the food that is for sure, but the little blokes are there going for it as well. I feed twice a day, sunup and sundown.
Muzza

Muzz - as you have them in the same tank, I would feed some big pellets to the big fish and throw in small ones/crushed ones at the same time so the small fellas are sure to get a feed. If they are not gettign as much as they would like, growth will be slow, which is not what you want.

muz, careful, if you have doubled the feed and the nitrates are still zero then your ammonia and/or nitrites might be elevated if the bateria need to "re-size"

just keep an eye on it.

Having regard to the nature of Murray's system I stand by my opinion expressed above:

All the same Muzz should do his full range of tests to make sure ammonia or nitrite don't get to unsatisfactory levels.

sorry VB, speed read the posts

yep, just saying to check the ammo + nitrites a day or so after doubling the feeding regime.

Thought as much