Greetings, I'm back. My research into aquaponics here in Phoenix led me to the hypothesis that maybe there was a simpler way of doing things that might make it more accessible to more people. So I took a couple of months to test the idea. So far so good. What you see here is what we call our "Floating Farm." It is just a small test cell. However by replacing technology with biology but it begins to address a few of the basic problems with aquaponics such as the roots dying for lack of oxygen, pH, complexity (one moving part) and cost.
The idea for this first go around was what would or would not grow in these conditions and how much produce and protein can be harvested from simply encouraging primary productivity. In the photo are: Loofa, watermelon (2 types), other melons (2 types), lettuce (3 types), squash (3 types), carrots (2 types), tomatoes (6 types), celery, beets, chives, onions (3 types), garlic, parsley, peas, beans, cabbage (2 types) and mint. Below in the water are freshwater prawns and a few other interesting things to balance the ecosystem. Water temperatures are a bit cool for the prawns but that is part of the experiment. Some things did not do well at all. Others have grown beyond all expectation. Likely due to the unusually cool weather the lettuce is exploding and will be ready for harvest within the week (about 45 days). We still have a long way to go with this again but so far so good.
I have a few hundred prawns for distribution to folks who might want to try some, free as promised. They are a low density species that don't take crowding well so 10 to 20 might be enough for most folks.
That's it for now.
G
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BTW I am teaching a free introductory class on arid lands aquaculture & aquaponics on the June 14th 2011 5:00pm and June 18th 2011 at 1:00pm. Here is the location and the website for details. Look under classes. If you are on facebook search for Intro Aquaponics Class.
Home Grown Hydroponics new store grand opening
RE: pH.
I am certain that when you get the pH down and stabilized many of your problems will be eliminated. I recently saw a product at the "Home Grown Hydroponics" store called pH down that might help.
We're also trying to figure out how to replenish the water once we get the PH down. In Dennis McClung's Garden Pool all evaporation condenses and runs back into the pool, so PH is constant. But in our system evaporation won't be returning to the tank. That means we have to replenish the water regularly with the high PH tap water.
Yes, we tried vinegar early on, but we didn't know how much to use and it seemed like we were putting quite a bit in with no noticeable result. So we did a test with buckets of water and were able to get it down, but it would have taken a tremendous amount for the large tank. That, and we've heard that the buffering that takes place can cause it to show no results for a while, and suddenly pitch down, which isn't good for the fish.
I did a bunch of research on driftwood, and learned that it doesn't have to be driftwood. We have a pecan tree and used some dry pecan wood, boiled & sanitized. That has worked, too in small amounts. We'd need a good sized branch to take care of the large tank, but we're using it in the indoor smaller tanks. The tannin does turn the water a brown color. I've heard peat moss does the same, but oh, well. It's a nice brown color, and it's clear. I'm hoping we'll be able to get results with a reasonable amount of peat. We'll see!
Tried vinegar and lemon juice. In my circumstance no effect for high (8.0) pH. This does not mean that in other systems it would not work however.
I don't have a full handle on all the details but this is what we believe we have seen:
1. High pH city of Phoenix water.
2. Fish in system release ammonia (NH3) which is also basic.
3. Carbon Dioxide (CO2) in water disassociates into carbonic acid as in a carbonated drink. Algae blooms responding to increasing nutrient levels remove CO2 from the water pushing pH up.
4. Balanced pH with Muratic Acid (HCl) but I have a water chemistry background so I would not recommend this to the pubic.
5. Bacteria residing on the roots, tank walls, water column and biofilter convert NH3 to NO2 (Nitrite) then NO3 (Nitrate). This reaction tends to push pH down and since it is continual, it stabilizes pH at lower levels. However since it is dependent on bacteria counts, usually takes 45 or so days for the right populations of the right bacteria to become established.
Hope this helps.
Sounds like we're fighting an uPHill battle! We went through the nitrification process when we first set up the tank, and because of an issue introducing sick fish, we ended up starting over & going through it a second time. It's been in good balance for the last couple months. The tilapia are handling the high PH quite well, but breeders need it lower. I was hoping to only worry about the breeder tank; alas, now we know that the plants need the PH lower as well. I'll keep you all in the loop as the next experiment transpires. :)
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