Backyard Aquaponics
A place to discuss aquaponics

About 30-50w per square foot is a good recommendation for light levels. Also, if your growing leafy green vegetables you could run the lights at night to extend the photoperiod and increase growth rate. Of course being so close to the fish they probably wont enjoy that.

Also I was wondering what you were using for a medium. It looked almost like soil. I haven't tried it yet for flood and drain beds but schultz has a product for pond soil and also a clay soil conditioner at home depot. Their supposed to be inert and I have used the pond soil in aquatic planted tanks. Having an inert media could help with nitrogen levels. Also adding a small biofilter- canister filter; wet/dry could possibly help.

The fish in my aquarium dont mind 24/7 light - they still sleep

Yeah I thought about running them 24/7 however I have tomatoes, peppers and strawberries so that would screw up their flowering I think.

We're using a combination of red cinder (bottom layer) and black cinder on top, its finer, and it seems to be working very well. we have a lot of fish, a 1:2 GB:Pond ratio and the water is crystal clear. I think the cinder offers much more surface area than other media.

Thanks for the interest!

unless you have a specific reason for doing so, usually 18 hours of light is as much as you would want.

you can find 400 HID (High intensity lights) for sale in classifieds pretty cheap. It doesn't have to be a MH (Metal Halide).. it can be a HPS (high pressure sodium). People use them to grow pot and you can almost always find them on craigslist. Here's one in S. Maui http://honolulu.craigslist.org/mau/grd/928945035.html. $225 for 600w light, ballest, reflector, etc. Probably got scared when you could smell his plants from his neighbors house. There was another one (1000watt) on there for $150 but there seemed to be some problem with it... dunno.

I use em to grow my veggie starts for spring planting. Lets them get nice and big inside while it's still cold outside. Flour lights aren't going to cut it. I think if you got a 150watt compact flour grow light you could get decent growth from greens but not anything that's going to flower and set fruit/vegetables.

Growing indoors also brings up an interesting situation with bugs. It's nice that they aren't eating your plants but it's not so nice when it comes to pollination. You can hand pollinate of course... I've never done it though.

i like how in the first picture of the blog there's 3 kids standing there with their hands in their pockets. by the end of the blog everyones smiling and getting involved. a++

FWIW I got my 400watt combo light (works with both MH and sodium bulbs and included both) complete from eBay for about $225. It even included a lighter!

You can grow under florescent lights. The main challenge I've had with doing that has been that you need the plants all to be about the same height so that you can place the lights as close to the plants as possible. And I mean really close as in you can't really reach in or look at the plants very well when the lights are close enough to the greens. The actual light tubes need to be only an inch or two from the plants. I grew lots of lettuce in hydroponics indoors when I lived in an apartment. I couldn't even reach in to harvest unless I lifted the lights up out of the way. If you are growing a variety of size plants, getting the lights close enough to the small plants gets difficult.

Yes I would say the spindly small plants are the ones that didn't have as much light. It isn't that you can't grow the plants in poor lighting conditions, the plants just won't do as well or grow as fast.

What are the lighting timers set for now? I found that if I had the lights on longer each day, the plants did grow better but I don't think 24 hours would be good, there are some functions that plants do at night. 16-20 hours of light could help you though.

TCLynx - I think lettuce would do alright under florescents but not tomatoes. They get to tall so that light gets diffused to much by the time it goes from the top leaves to the bottom leaves.

HN - some plants are triggered by photoperiod and some aren't. apparently most garden vegetables aren't (I just read that somewhere...on the internet, so take that for what it's worth.) tomatoes also aren't one that are triggered by photoperiod. apparently once a tomato plant matures it fruits.

The lights are set to 18 hours a day. Things are actually grwoing really well. I'll try and get some pics up soon.

The big problem we;re having is that the strawberries aren't flowering. They are growing well, just no flowers. I think its because one of the ceiling lights are left on at night for safety reasons.

I'm looking into some LED grow lights. They are less expensive that HID lights (lower lumens obviously) but seems like they might work well.

Thanks all!!

Aloha Hawaiian Newbie

There's an offer to help at the end of this post, but most of it is about the nitrite spike during AP system startup.

I just read your early posts on starting your system and surviving the nitrite spike and wish I had known about you, cause we had an answer to that problem back then. We developed a method of quick-starting systems and dealing with the nitrite spikes a hard system start causes. I took the UVi (University of the Virgin Islands) Short Course a year ago, and they told us when asked about how to start an AP system "Just wait two to three months and the nitrifiers will show up all by themselves". Of course, in a commercial situation when you are paying a monthly note and electrical bill that can be kind of annoying to waste so much time with no fish or plants in a system.

Even using this waiting method on the first system, we still had a nitrite spike that went to 10 ppm on the test strips, and I suspect may have been higher than that, because the test strip developed its full violent pink color that indicated 10 ppm about four seconds after it was dipped, instead of the full 60 seconds development time.

We found Aquatic Eco's product #239211, gallon size of nitrifying bacteria for $43 plus shipping and after the first system we started, which took two and a half months because we just waited, inoculated our systems with that. The techs at Aquatic Eco were really helpful. The next 20-raft system we started with this inoculant bacteria and got 3ppm nitrites within three days and nitrates showing up within 5 days, then we planted into the system. This was with a full load of fish in the system, almost 800 lbs.

Problem was that the nitrites spiked at 10 within another three days and stayed there for two weeks before coming down. We didn't know any way of dealing with this; and since it is an 11,000 gallon system and we are on expensive (and chlorinated) city water we didn't have a way to economically exchange water to dilute.

Fortunately, we have a bunch of toughy tilapia who just endured it all. For the next 36-raft system we started we had a brainstorm: the nitrifiers are light sensitive, so when the nitrite spike kicked in, we removed rafts to partially uncover the troughs and removed shade covers from the tanks to let light in. Nitrites went down to 3-5 ppm from 10 overnight, stayed at 3-5 for two weeks, then went to 1 or so, and we covered the troughs and tanks back up. This system had about 1,500 lbs of fish in it when we started it. Everything was fine and we were planting five days after system startup. During normal operation our systems run around 0.5 ppm nitrites, 20-80 ppm nitrates, and 0.5 ppm ammonia; pretty steadily for months at a time.

Now I read some posts about adding salt or chloride to moderate the nitrite spike, and don't mean to contradict those who posted. I am just parroting the UVI stuff I was taught, because I have never put salt in an AP system, but doesn't it negatively impact the vegetable growth? Does anyone have experience with salt in these systems?

Back to our offer to help: My wife Susanne and I run a commercial family aquaponics farm in Honokaa, Hawaii that has been in operation over a year. We've been helping the local high school ag teacher at Honokaa High School, Manuel Jadulang, put in an 8-raft aquaponics system for his kids modeled after our systems, which are modeled after the UVi (University of the Virgin Islands) systems.

If there's anything we can do to help you with your aquaponics please let us know. There's also material and contact information on our website: http://www.friendlyaquaponics.com. We had teachers and students from four high schools on the Big Island at our 4-day Commercial Aquaponics Training in October 2008, and two teachers from Kauai. Where are you located? We'd love to see pictures of your operation and help get you hooked up with the other schools and teachers who are doing aquaponics in Hawaii if you're interested. If you guys work together there's a good chance you could get DOE or grant money for your aquaponics program.

Tropic, salting to 1ppt moderates the "affects" of nitrite on fish ... specifically "brown blood" disease... its effectiveness is due to the Cl- ion and relationship to osmotic balance...

Salting has a "soothing" effect in general stress on fish... and is often used during bag transport of fingerlings and even "live" transport...

At 3-6ppt it is used as a common treatment for parasites (Ich in particular) and fungal infections, wounds etc...

Severe infections are often treated in a "salt dip" or "salt bath" of anywhere up to 12ppt, depending on species, from 10-30 mins...

Often this ameliorates the need for treatments like formalin.... obviously tank/pond size and stocking density limit the application of salt treatments.... 3ppt is 3kg/1000L....

Salting is not only commonly utilised in aquaculture, particularly in isolation tanks, purging tanks....

But is generally the first port of call in the majority of backyard aquaponic systems...

Salt is great

Anything up to 3ppt does not really harm or retard plant growth at all. Except for strawberries

We really need to find a strain of strawberry that can handle the salt.

The raspberry seems to be doing ok so far - I'll take that