Backyard Aquaponics
A place to discuss aquaponics

The boys have covered it well.

Muz, 2 PPT shuld be fine for the plants.

As VB said, post your readings, probably the easiest way around things is cut feeding rate (say to half) this will give the ammonia a chance to drop, at which point you can safely raise the ph a little higher, its a double edged sword, the ammonia and ph thing.

As monya said, make sure that the shells are in a path of water, and smaller pieces work better too.

Steve

Monya, well observed, there are little mites and a fine matting of web - any ideas on how to shift them? I just thought they were small spiders!!!

I have broken shells burried in the grow bed and also in the tank, perhaps I don't have enought!

Will post the Amonia and PH readings tonight......

red spider mite - google it

PH 6.2 and Ammonia between 1-2ppm. I even have 1L of zeolite chips in the external filter too. This has been sitting like this for 3 or so weeks. I just can't get it down, even when I have stopped food for about 3 days.

Feeding for 29 fish (2-3 tea spoons of Native Fish food)..... on occasion, worms, flies, maggots etc.

Definitelly want to work that ph up some. Are you F&D or continuous flow Marcus?

Flood and drain. Fills in 3 mins and takes 1 hour to drain. Runs every second hour during the day and on the hour past 5pm due to limitations of the timer.

Other than tonnes of shells, other thoughts on getting the PH Up?

I personally think that the infrequent cycling would be a contributing factor to your problems, particularly where the bacteria are not working well because of the PH.

Work out how often the tank turns over every day - it will not be a high number, your tank looks pretty big.

I also have a Murray bed as you may know. I also use flood and drain, but use an autosyphon and have the pump running continuously. Flooding the bed takes about 8-9 minutes. Draining takes about 7 minutes - air suck starts at about the 4 minute mark.

I estimate that I am turning over about 25 litres a minute. With approx 1500 litres of water in my system (fish tank and sump), I am therefore turning over this water once every hour or 24 times a day.

You are turning over only a little over 1.5 litres a minute during the day and 3 litres after 5pm. Compare the difference. The more I think about it the more I think this is a major problem for you.

In addition, this long drain cycle will mean that the oxygen levels in your bed will become depleted, particularly in the lower part of the bed - which will inhibit plant growth and bacterial gorwth.

Marcus, I have a mite infestation that is wrecking my system. All m,y plants are suffering it is heartbreaking. By the time I realised the problem it was too late. As you know we can't spray, but there are things we can do. There is a mob in Sydney that sells persimilis, a very active spider mite eater. I am getting 2000 of them delivered next week. It is costing me $49.50 incl postegae and they should clean them up really quick apparently. However, the first thing to do is remove all the leaves with webbing on them, they are beyond saving. The predatory mites workl best before it is out of control. Currently, I am losing capsicums, beans and cucumebers, cucmbers are their fravourite. PM me if you want this mobs contact details,.

The predatory mites thrive in a compost/humus sort of environment, hence orgainic gardeners have a good natural defence against the mites, but we are lacking in an environment for them. The mites have the potential to completely wipe oyut our crops. What worries me is the nitrate removal should we have to remove affected plants as they suggested to me.

On your ammonia, you need to cycle your system more often. You will find it helps a lot.

Stu

i think VB has hit it on the head for you. I'd agree increase the LPH rate.

I know F&F runs the same sort of F&D cycle times as you, but he has almost 2000L of gravel (i think) (bigger bac. colony)

Hi Marcus:
What kind of test kit are you using - is it a strip test or the one with the eye droppers? I found out how wrong my strip test kit was after getting the drip kind - the strips said pH was less than 7, the drip kind says > 7.6. I had thought that all the shells added had not changed anything but turns out they had.

Appreciate the input. The limited circulation had been a concern for mine from the start; hence I bought an external canister filter. As an approximation the tank whole volume cycles through the canister filer once an hour, whereas the whole tank cycles through the grow bed approximately once a day, which is obviously not enough.

Attached is a photo of the drain from my grow bed, as you can see I am presently limited by the volume of water which can leave the grow bed, it presently takes an hour. VB, you mentioned that you also run an auto siphon, can you please refer me to picture (or direct me via a link) to show how your system works? If I can get the water to exit the grow bed faster then I can move towards a continuous flow system (fingers crossed!). At this point I can’t fathom how that increases drain from 1 hour to 7 mins!

I will try and spray the mites with an “organic compound” - http://www.greenharvest.com.au/pestcont ... _info.html

For PH testing I drip 3 drops of regent into a sample of tank water and hold it against a strip to get an idea of colour.

MArcus I sprayed with the water milk and flour mix to no avail

I have tried experimenting with the flow and drain of the growbed - after removing the standpipe from the drain of the growbed (bloody obvious on reflection!) it now drains in about 15 mins.

However this has now given me another issue to contend with: my pump is too powerful (even chocked back) for continuous flow and my timer only allows for 14 on/offer per day, so I guess I have two options:
1) Buy a new pump (which I would prefer not to do) or
2) Find a timer which can turn on for say 3 mins, off for 15 (while the grow bed drains) and on again for 3 mins etc

Can anyone suggest a brand of timer which can do this?

good luck! The 14 onh/offs is what I use on my big system. My fingerling tank has 15 on increments, so even though I only need the pump on for 3 minutes, it flows into the stanpipe until the 15 minutes is over. But I need it on every hour so that is as good as I can get. The other option is to use a float switch,. I personally find them very frustrating, so will stick to the timers

I have a float switch on my Grundfos pump, however, when the tank empties, there is not enought "drop" to turn the pump off and vice versa, hence I opted for the The 14 onh/offs - which on reflection is not enough.