Does your system ratios change with the crops you grow?

[Kobus Jooste]

I posted this in the advanced group as well but thought I should toss it in here too.  At the onset of my system, the design ratios was just within acceptable levels of component ratios according to Dr Lennard's calculator, with the suggestion that I should have a look at getting some more sump volume in there. 

 

Over time, however, I have noticed that my interest in growing permanent fruiting crops in stead of a permanent flow of leaf crops have seemed to have an adverse effect on water quality.  I think that the root mass of my permanent stock is slowly eating up the void space that the gravel beds would have employed in the past to trap solids.  I have much moresolids in my water column than before, and am actually feeding less as we reach the end of summer here.  What I am wondering, is whether the culture of fruiting crops should alter our ratios in design to include more gravel beds than required toi compensate for the permanent root mass that develop in our beds.

[Adam Shivers]

maybe we could develop dividers in the growbed that allow for growth of area by adding it as needed. just a thought. you know, fill the next section with media (gravel in this case) and pull the divider out... viola... new ratio? Now we would be dealing with a projected amount of proper space that could buy some time to harvest more from our already established system.

[Kobus Jooste]

That would be one way of doing it - quite a nice thought, as I think a large bed eventually is better than a whole lot of small ones.

[Two Jay]

Looks a little like M.C. Escher's work.. good looking art you have created.

[Izzy]

How's your pH?

[Kobus Jooste]

You have lost me there - can you point out what you are referring to?

Two Jay said:

Looks a little like M.C. Escher's work.. good looking art you have created.

[Kobus Jooste]

Last time I checked it was just under 7, but that has been a week or so - working on the house now thus no time for much else.

izzy said:

How's your pH?

[Kobus Jooste]

Having watched the situation for a while, I am now positive that the original mixed system I made is in need of augmentation.  One of the three gravel beds now definately belongs to the passion fruit.  I have removed the one raft from the bed and turned it into a fines filter for a while.  This has cleaned the system up very nicely.  I will now be turning that bed back into a gravel flood and drain bed.  This will give me a "Core of gravel beds that will be the lungs and filter of the system.  Around this, I will stack NFT-style pipes to grow at maximum density with the least amount of infrastructure addition.  I will provide updates as I go along.

[Izzy]

What exactly prompted the concern to bgin with? A problem with ammonia or something else?

[Kobus Jooste]

A combination of deteriorating water clarity, changes in the flood and drain rates and volumes observed in the beds, and the fact that I always had a bit more ammonia than what I really wanted.  Did not loose any fish, but I always felt the system could do better

[Izzy]

You may just need more grow bed space. Also, it takes a while for systems to mature. Lastly, with such a problem with your gravel getting mucked up I'm surprised no one suggested worms. My worms are amazimg and keep the roots perfect as well as the grow beds flowing. I actually have very little grow bed to water. The system stays near 0 ammonia and the plants are great. There are so many ways to do this as long as you know what is going on in YOUR system! :)

[Kobus Jooste]

First, the system in its current configuration is over a year old, thus well past teething stage but still capable of improvement.  Second, it was scaled quite carefully according to literature, but as the system gets messed with for experimentation, some issues may develop.  Lastly, I've known about worms for a very long time, but remember I am in a relatively under developed province of South Africa.  Having "worms" suggested and tracking them down is not as simple as everywhere else.  I could have found them sooner IF I really obsessed about their use, but the beds are being clogged up by healthy roots and not solids.  Don't think the worms will do much to the root issue as it is growing plants and not left-behind roots that is the issue.  Water quality is related to fines going straight through the gravel so again, worms would not have helped there - it took fine filtration to reduce the fines levels. 

[Izzy]

The African Nightcrawler is not native to your region? It is an excellent worm! Water clarity wont affect the plants or fish, but I have found that a gravel biofilter that has constant flow and no violent water flow traps solids amazingly well. That's how I clear up my water in a short amount of time before any tours :)

You could always raise the pH a little higher so that your bacteria can do more work.