Problems with indoor system

[crosshairs]

Hello,

Been reading the forums in tandem with my first real aquaponics experiment. First time posting.

I've had unimpressive results thus far and I hope I can get some recommendations. Here are some specs for the system:

• Size: ~45 gallons (tank is 55 gallons, but the grow beds aren't that big so I don't fill it all the way)
  Grow bed medium: Hydroton
  Circulation: I have two pumps continuously pumping water into each grow bed respectively. Each grow bed has a loop siphon. Fully fills up and drains every 10 minutes or so. Note that the water comes up to within an inch or so of the surface of the hydroton. Maybe this should be lower, but I wanted to expose as much of the hydroton to the water as possible since the hydroton is only about 8 inches deep.
  Fish: 5 wild caught Bluegill from a nearby lake (Well..., 2 are pure bluegill, 3 are warmouths or some other lepomis variant).
  Age of the system: ~4 months
  PH: Consistently between 6.8 and 7.2
  Ammonia and Nitrite: Consistently at ~0
  Nitrate: Consistently high (between 40 and 80ppm, more on this later)
  Plants: Bush beans, snap peas, peppers, chives, lettuce, carrots
  Lighting: Each grow bed has a fixture holding two 24" F20 20 watt 6500K daylight flourescents. The grow beds are also just inside south-facing windows that get a decent amount of sunlight.
  Aeration: There is an aerator within the tank constantly making bubbles. I also have the loop siphons situated so that they produce lots of bubbles when they drain.
  Minerals: When I need to buffer against low pH, I add a limestone supplement containing calcium and magnesium, among other minerals.

That pretty much describes it. So here is the list of issues I'm having:

• I have a mite problem (looks like two-spotted mites to me, though I'm not sure). They came onto the scene about a month ago and decimated my beans and peas. I have had to uproot many of my plants owing to them. Currently I manage the problem by manually inspecting the underside of every bean and pea leaf, and smashing the mites I can see. This keeps them at a manageable level, but it is time consuming and if I don't repeat at least once a day, they get out of control and kill leaves. From what I've read online, they can be controlled by introducing other types of mites that eat them. The wife and I are hesitant to intentionally introduce something called a spider mite into our kitchen, which is where the grow bed is. Has anyone else had problems with these guys? Any successful techniques to get rid of them?
  Even before the problem with the mites, the system got fusarium wilt or something similar, which is still present and affects the peas. I've seen it in non-aquaponic gardens before, and it works exactly the same way here - the plant slowly dies from the base of the stem up. The peas typically are able to produce a pod or two before ultimately succumbing. I suppose the solution is to look for disease-resistant seeds, but just wanted to bring this up in case anyone has other suggestions.
  Even apart from the mite and fusarium problems, the growth rate has not been impressive. The beans typically have had the best growth rates, but even before they mites took over they were only growing about as fast as beans do in regular settings. The lettuce you see in the pictures below is at least 6 weeks old (several are much older), and just doesn't seem to want to grow. Same with my pepper.
  Nitrate levels are consistently too high. Probably because there's not much plant life, but even when the legumes were growing decently well the nitrate was way too high. I read elsewhere that, even though legumes are nitrogen fixers, that they still take up plenty of nitrate when in an aquaponics system. Hopefully I was not misled.
  The bluegill will not pellet train. They're wild fish and several are fairly old, but even the smaller ones won't eat the pellets. I've been feeding them very sparsely for the past month or so, and I'm frankly surprised that none have starved to death yet. The bluegill are trained to know that I provide food and any pellets I drop in the tank go right into their mouths, but then they spit it out once they realize what it is. Per instructions I've read, I have soaked the pellets before dropping them in, to no avail.

Also, as you could probably surmise from the pics, I do have some algae growup in one of the tubes entering the grow beds, and on the walls of the grow beds facing the window. I believe I could get rid of it pretty easily by covering the wall so that sunlight doesn't get in. I haven't done this because I want the algae to consume nitrogen and hopefully lower the nitrite levels, and because I know the tank is plenty aerated.

Here are the pics of the system. I have more pics and can post them on request.