Backyard Aquaponics
A place to discuss aquaponics

I may have designed and built a system larger than I should have. I enjoy building and inventing. In the summer of 2013 I got all exited in what I thought was going to be a nice Aquaponic system. Over the years however I’ve had limited success and always seem to be distracted by other responsibilities and new ideas. Finally I thought of reaching out to folks who I’m sure know more about this stuff then I. If I could get to where I understand how to make my system work properly it would be awesome. But I’m having a difficult time understanding things. It seems like there are many different potential issues. I was hoping some of you experienced folks could shed some light that would point me in a direction leading me to some understanding.

I’m off grid here in TN and using rain water collected on the greenhouse roof. At first I was excited that my water would have any of the bad stuff city water can have. But then the reality struck home that there was no good stuff either. Rain water has nothing in it to start with so I need to add everything. It’s sort of like using distilled water. I’m having a hard time being sure I’m reading the water correctly. Of course I’m using the API test kit but feel I need to go beyond PH, Ammonia, Nitrite & Nitrate.

Current Water Readings:

PH - 6.8ppm
Ammonia - .25ppm
Nitrite - 0ppm
Nitrate - 60-80ppm (I think… It’s hard from me to really be sure I’m reading the color chart accurately) it’s been much higher at time and I simply slow down my feeding.

The growth in the media bed seems to do well but has a hard time with reproductive growth. Growth on the rafts in the sump have vary pronounced veins in the leaves but I’ve not been able to determine what the deficiency is. It would be nice to know how to test for Phosphate, Potassium, Calcium, Magnesium, Iron and such. I have purchased $200 worth of test kits to try and get a handle on these areas. But between not being sure I understand them correctly and not being able to read the signs my plants are giving me I feel I’m lost for lack of understanding. I’ve added at different times Rock Phosphate, Potassium Carbonate, Calcium Carbonate, Chelated Iron & Magnesium (Epsom Salt) all going on readings from these test kits that I’m not sure I’m using correctly.

I’m aware that Phosphate is key for fruiting (reproductive growth) but I’m not sure how to test for it. I’m using a API Phosphate kit but it’s never read more then 1.5ppm. I’ve added several 6 oz. containers of Rock Phosphate in the media bed where to water comes in from the tank. I’ve never found in make much difference in my readings even a week or too later. I’m concerned I could be pushing close to an algae bloom.

I think it’d be better to answer any questions rather than load up this first cry for help with information that may not be needed. I think what I’m lacking is true understanding. I’m hoping my system may only need some minor tweaks.

Thanks in advance for all your consideration…

Welcome

Just looking at the plants in your setup I think you have a couple of things going on (none too serious looking though). There is pretty tight plant spacing which might be contributing to the larger dead leaf portions (maybe a small disease issue or I suppose it could be caused by leaf miners). It looks like you have a couple nutrient deficiencies. Before I get into that I think it would help you to think of plant nutrients as either mobile within the plant or immobile. Potassium is mobile so it gets moved to the newer leaves as they grow, often you see this deficiency showing up as dying leaf margins on the older leaves - I think you may have some plants showing this issue. It also looks like some of the plants have lighter yellow leaves that are part of the new growth - this is usually because of an Iron deficiency - Iron is not easily moved within the plant so that's where this deficiency shows up. These are the two most common deficiencies in AP. You can look online and find information on which nutrients fall in which group - mobile or immobile within plants.

I'm not sure if you're applying anything to cure either of these. There may be another issue causing the leaf puckering but I'd say work on the first two and see if it helps. For what it's worth I usually adjust the pH (which is constantly but slowing falling until adjusted up) using a potassium bicarbonate or potassium carbonate addition and this takes care of potassium for me (I alternate this with Calcium carbonate in the form of crushed coral or shells in a mesh bag hung somewhere in the water). The Iron in my system is adjusted using a spray application of Maxicrop plus iron but many people use iron chelates like EDDHA or DTPA instead. pH is important in iron additions to system water but not as critical if you spray apply (different types work best in certain pH ranges because of their availability, spray application avoids some of this problem).

Many of these nutrients come from the fish food you are using. If you aren't using a good quality commercial feed that could also be part of the issue... although usually people have to add Iron and Potassium to their AP... occasionally other things but not too often.

Some of the people around here use rain water and can probably advise you on the best way to remineralize that if you need some help.

I wouldn't add anymore rock phosphate. Most of the time my AP system doesn't have a phosphate reading and there is phosphate in commercial fish feed anyway so you're probably already adding it.

Your readings look fine. Hope this helps.

I think you're test kit addict

When you start adding things to the system you may cause a lock out of something else.The "idea" of aquaponics is that the fish produce the nutrients formed by naturally occurring bacteria (not synthetic salts).Adding all those things,it's now a hydroponic system.
You should only add something when it's needed & if possible,foliar spay it so you don't cause some sort of a nutrient lock out.

Phosphorus is probably the least common deficiency in aquaponics,so I wouldn't worry about that.There could a number of reasons why a plant isn't fruiting up.


Sometimes if a test kit is over whelmed it can give a false reading.

The rain water issue,I use pure water only (0ppm) & it's buffered with shell grit.The test you're talking about is GH test (general hardness) that's for seeing the quantity of things in the water but most of those tests are reading for Calcium & Carbonates.Maybe a TDS metre will help with rain water.

There's a couple of things you haven't said;
What are you feeding the fish?
DWC part,are the roots nice and clean? Is the water filtered before it comes in?.

Sorry It's taken me a few days to get back...

I'm sure I'm not... I got what Im using at the local Tractor Supply $15 - $20 for 50lbs. It's the sote of stuff you'd use in you backyard pond for your catfish.

Could someone point me in the direction of some think you folks would consider a good quality feed. I just rather not spend top dollar if there are areas to learn with the cheeper stuff. But then I guess I could be learning what the cheep stuff effects my system.

I really have no filtration in the system at all. I usually take a small pool type vacuum and remove any solids developing on the bottom of the fish tank when they begin to be noticeable. I can't say there has been much of that however certainly not an alarming amount. I simply collect it in a fine sediment type sock and bump it in the grow bed. There really isn't much picked up and the water seems fairly clean.

As for the roots in the DWC I'll take a picture of them tomorrow to get your opinion. I'm not sure what I'm looking for. I will say the deficiency does seem to be completely in the DWC or Sump growth. The Growth in the media bed doesn't seem to have the visible yellows veins in the leaves as seen in the DWC. While the first smaller broccoli in the media bed pict does show some deficiency I had just transplanted it from the DWC to see if will show an improvement.

Thanks for your input.
I will try and answer more quickly in the future.

In the states Purina Aquamax is good, no idea about other brands. Whatever you get make sure it says it is a complete diet on it and not just supplemental feed.

Purina is probably the easiest to source but Skrettings is also available but probably would need to be shipped (They have a facility in Utah). Farm stores often have large bags. I'm not certain what kind of fish you have or how much feed you would need so it's tough to advise you on this... You might not need that much feed depending on what your fish load is -- you can find smaller bags for sale on EBAY. The feed will vary depending on the type of fish but usually higher protein feeds that are pellets and not flakes work best for AP. Keep in mind you'll be feeding more in the Summer (since the fish eat more) so your plants might do better then even using the same feed you have now.

As for fish I have 19 three year old goldfish. They are about 6 to 10 inches in length. They are doing well at this time with the floating pellets. I'm not wanting to eat anything at the moment. I'm just trying to learn with I fish that are hard to kill.

Goldfish are great for that Beyond the occasional 1-2 right after stocking I think I've only had one die on me.

I also saw this feed brand called Optimal, they have a aquaponics formula fortified in iron/phosphorous/etc. so you don't have to supplement. Never tried it though so no idea if it's really good.

It seems strange it's only in the DWC bed.So it can't be a deficiency in the system if the plants in the gravel bed are ok but not in the DWC/sump.
Does the water flow; fish tank - gravel bed - DWC/sump?.Maybe there's not enough nutrients to go round.

What Scotty said about spacing might be an issue too.I can't see the leafs that well from the pic but are the leaves yellowing where they are touching other leafs?

I was going to mention about how many fish you have,because I thought I saw 9 gold fish in your sig,but now it says 19 & after looking on google to convert gallons to litres,I realised how big your system is.From your pic of the gravel bed,you only have a few plants in there,I think you're going to need a lot more fish when that grow bed is full.
Your Nitrate has a good reading but the lack of fish will also contribute to lacking other nutrients.You have to find the balance of keeping the Nitrate within acceptable levels & feeding the fish enough so other nutrients are floating about.

DWC always needs filtering.You won't see the fines in the water.Once they cling to the roots,it could prevent the roots getting water & air.