Nutirent Issues...Maybe?

[Thaddeus J Dick]

My system is a 40 gallon grow bed and a 100 gallon tank with approximately 30 fish, gold fish and catfish.  My intent was to cycle the system and establish a healthy grow bed.  I started on 4 July.  As of today, 15 September, I have red chili pepper plants approximately 2 feet tall with flowers ready to bloom.  I've also got swiss chard, a strawberry plant, lettuce, and some pumpkins growing in the grow bed.  The swiss chard has produced, and while the other plants are thriving, nothing producing yet.  All of this is in a greenhouse in Georgia.  My ph levels have consistently been below 6.4 and I can't seem to get the ph level raised.  Ammonia level has never been above .25 PPM and my nitrites and nitrates levels hover around zero.  The fish are happy and eating and apparently doing what they're supposed to do.  I've also introduced worms into the grow bed.  My concern is my buffer isn't as healthy as it could be and not providing the nutrients for the plants.  Perhaps I have too many plants?  I intend on adding another 40 gallon grow bed this week and starting some fall and winter type plants.  System works great; however, it just doesn't seem to be producing produce from plants at the rates I thought it might.  Water temperature has never been above 86 F and with the onset of cooler weather, it is probably closer to 80 now.  The greenhouse typically gets to above 100 F in the late morning to early afternoon.  Again, plants are healthy and all seems to be thriving, but it's been over two months now and my levels just don't seem to be where I believe they need to be.  Comments and suggestions would be greatly appreciated!

 

[Alex Veidel]

You're probably going to have a hard time growing, say, pumpkins in your aquaponic system. Anything with large fruiting bodies take a larger nutrient load. Cucumbers, green bell peppers, melons, etc. Red chili peppers aren't a bad choice.

You can use potassium bicarbonate to stabilize your pH. The bicarbonates will raise your carbonate hardness, which will act as a buffer for your pH.

[JoAnne Bell]

Hi Thaddeus!

 I agree with Alex the potassium bicarbonate may help stabalize your pH. If that doesn't work, try crushed coral.

 We have a 90 gal fish tank that I started up around the same time as you started yours. I had the same issue with my pH. Potassium bicarb didn't help at all. (It had helped some of my other systems, but not this one.) I added 12 oz of crushed coral every 3-5 days (when my pH dropped to 6.4 or less) and my pH stabalized when I reached 48 oz. It has stayed between 6.8-7.2 for the past month.

 As for plant production, correcting the pH may solve your problem, as well as time. Your system is less than 6 months old. So it's still young. After 6 months, when bacteria are better established and your fish are a little bigger, you may see better results. That said, let's make sure there aren't any other issues. I'll need some more info to do that:

1) Could you show us some pictures of your plants? Ideally, a mix of pics including: the entire grow bed, individual plants and close-ups of discolored leaves.

2) How often do you feed them?

3) What size are your fish?

4) When did you add plants? Did you start them in the system as seeds or transplants?

5) What are your harvesting expectations?

Thanks, Thaddeus! I know that's a lot of questions. But the more info I have, the easier it is to diagnose the problem.

JoAnne

[Thaddeus J Dick]

JoAnne,

 

Thanks for your response.  In answer to your questions;

- I'll try attaching pictures when I get back home this evening.

- I have approximately 25 fish, including two catfish, and I feed them once a day.

- The biggest fish is approximately five inches long; it's a catfish.  Typically, the fish are no more than four inches long.

- I added plants immediately and started everything from seed, with the exception of a later addition of a strawberry plant and a pumpkin plant.  I now have lettuce, swiss chard, and red chili peppers as well.  It seems as if the plants are really starting to grow, especially with the onset of cooler weather.  Everything is in a greenhouse.

- I would expect to start harvesting some leafy vegetables as we move into fall and winter.

 

I just added a second grow bed this weekend.  My ph level is at approximately 6.8.  My ammonia level went up some, but I have detoxified the ammonia.  I'm not very concerned.  I did start some lettuce seeds in the new grow bed.  I haven't added the potassium bicarbonate yet. 
 
JoAnne Bell said:

Hi Thaddeus!

 I agree with Alex the potassium bicarbonate may help stabalize your pH. If that doesn't work, try crushed coral.

 We have a 90 gal fish tank that I started up around the same time as you started yours. I had the same issue with my pH. Potassium bicarb didn't help at all. (It had helped some of my other systems, but not this one.) I added 12 oz of crushed coral every 3-5 days (when my pH dropped to 6.4 or less) and my pH stabalized when I reached 48 oz. It has stayed between 6.8-7.2 for the past month.

 As for plant production, correcting the pH may solve your problem, as well as time. Your system is less than 6 months old. So it's still young. After 6 months, when bacteria are better established and your fish are a little bigger, you may see better results. That said, let's make sure there aren't any other issues. I'll need some more info to do that:

1) Could you show us some pictures of your plants? Ideally, a mix of pics including: the entire grow bed, individual plants and close-ups of discolored leaves.

2) How often do you feed them?

3) What size are your fish?

4) When did you add plants? Did you start them in the system as seeds or transplants?

5) What are your harvesting expectations?

Thanks, Thaddeus! I know that's a lot of questions. But the more info I have, the easier it is to diagnose the problem.

JoAnne