4 month old system seems lacking nitrogen

[Roland]

I have a CHOP 2 system set up based on a 65 gallon tank and 30 gallon sump and feeding a 4 cubic foot grow bed under 250 watts of T5 fluorescent lights. I have probably 25 small goldfish and two large (5") goldfish plus some algae eaters. I have a tee in the main water supply line from the sump which allows water to circulate into the tank (seems good for the fish and the idea was that it would help to reduce resistance on my pump), it then carries on up to the grow bed. So my medium is Grow Stones, and I have herbs planted in the grow bed. Can anyone suggest why my basil and mint are looking light green and perhaps lacking nitrogen? Is the tee into the tank somehow stealing my nutrients before the water makes it to the grow bed? I just added some red wigglers the other day in hopes that this will help with added nutrient up take and minerals.
Any suggestions? Am I lacking fish? By the ratios, I am circulating my tank every hour and I have a bell siphon.
This is my first time on this forum and I am excited to share knowledge. This is my 4th aqauponics build so far and I have big plans! Any ideas would be appreciated.
Roland

[Alex Veidel]

Have you tested your water? What are your levels at?

[Roland]

That seems obvious I suppose. I have a kit and this will be my next step.

[Chris Griggs]

the fish density does seem low for such a large grow bed.  also depends on how many heavy feeding plants you have as well.  any fruiting plants will take way more nitrogen than leafy greens will.  i have had similar issues and added very small amounts of blood meal to base of affected plants with decent results as a quick fix until my fish density can be raised.  have to be extremely careful though because the blood meal with spike ammonia, then nitrite, then nitrates so have to monitor carefully and it takes a few days in my findings

[Roland]

Got your tip on the blood meal. I added red wigglers (about 20 or so little ones ) as well. This should help I'm thinking. Next step is to add a few more big fish. Also I was reading about ratios and know I should have twice as much grow bed as tank. Right now I only have a 4' X 1' grow bed to the 65 gallon tank, so I figure as this system matures I will add a few hanging planters with strawberry plants.

[Roland]

Did a water test. Nitrites are very low, ammonia very low, pH about 8.4 (apparently this is still good for goldfish). Any other ideas as to why my basil is so light green? I have plenty of light. Maybe I just need more fish.

[Chris Griggs]

The pH is good for the fish, but bad for the plants. They might be in nutrient lock from being too alkaline. The plants want anywhere from about 5.5 to 6.5. I keep mine at about 6.8 to keep happy medium. My tilapia or goldfish seem to mind. What did nitrate level read??

[Chris Griggs]

As long as ammonia low or 0 and nitrites are low (.5 or less), you are getting good conversion. Nitrates are what you want and shoot or about 30 ppm

[Roland]

Didn't have a test for nitrates, only nitrites. That theory about the pH sounds right. I will buy the liquid that lowers pH.

[Chris Griggs]

Citric acid can be used and it is avail at Walmart in the canning isle. Doesn't hurt fishes:) just fyi

[Bob Subrainibility]

LOL

Roland said:

That seems obvious I suppose. I have a kit and this will be my next step.

[Alex Veidel]

Roland, test for nitrates. Nitrates are your plant's source of nitrogen. Meanwhile, if you could post a picture of your basil, that would be great. There are lots of deficiency symptoms that cause yellowing in the leaves; it all depends on the kind of yellowing and where in the plant it is. Are the leaves yellowing, but the veins staying green? Did it start in the new leaf growth or the old leaf growth?

Roland said:

Didn't have a test for nitrates, only nitrites. That theory about the pH sounds right. I will buy the liquid that lowers pH.

[Chris Griggs]

Alex is correct as well. Calcium, potassium, and iron are difficult to naturally introduce into these systems. A pic would really help to see if its a mobile nutrient or immobile nutrient deficiencie.