Backyard Aquaponics
A place to discuss aquaponics

Hi guys,

I am a newbie to aquaponics living in the Philippines. I have had my system running for around 6 months now starting with just a couple fish for the first few months to get the bacteria running.

My system I built myself with local materials. Grow beds are 4fX8ftX 12inches deep. Im a go big or go home kinda guy LOL, I have three of those now but have room for 7 and a 3000 ltr fish pond that now has roughly 120 tilapia. The 20 was from the first stock of 100+ that 80 or so died due to transport Im pretty sure. They were brought from the province in a bag taking around 3hrs to arrive. Im sure the province folk dont use oxygen like the fishery where I got the last 100.

Ok on to my questions.

How much Seasol would a system this large need to keep it up on micro nutrients. Its roughly 4500ltrs including my grow beds. Two CF and one FD. I have had several plants going and none have really taken off like I would have expected. Oh yea I should mention that I havent found any Seasol here but they do have a kelp fertilizer called Natures Bio that looks very similar. Has bat crap and all LOL. I have also added a product called Aquaponic elements that contains trace minerals and such.

My Plants

I started with a few tomato plants that grew very well and started to flower but most of the flowers just died. Did some research and it was most likely the heat and/or humidity so I think I have that solved for next time.

My strawberry plants are a different story. They looked great for the first couple weeks after transplant but now they are turning a bright yellow (some almost white) looking like iron deficiency. However I have a sulfate mineral supplement I use for myself that is high in iron. I made a spray with it and dowsed the plants for a couple days with no reaction. Maybe sulfate minerals cant absorb in the leaves? Ok so on to the next potential culprit with calcium. I did add a bag of corals to my fish tank setting just above my bubbler to get good circulation and break down of calcium and still no joy. Maybe need more? Last but not least I thought maybe its magnesium so I made an epsom salt spray and dowsed them for a couple days and again no joy. I do not understand what is going on and even though the plants are flowering and making runners they look like they are fixin to die.

Just for a FYI I tested my amonia, Nitrites, Nitrates and PH last night and they read as follows

Ammonia- .25
Nitrite- .25
Nitrate 80+ ppm
PH 6.8

I did stop feeding the fish until the ammonia and nitrites drop but that should be soon.

Any suggestions would be appreciated greatly

Welcome to the forum Cdt

If you can post up some pictures of the strawberry plants that would probably help but it does sound like iron. What you should be seeing is just the new leaves showing yellow or white (really severe shortage) because iron is not mobile within the plant. A plant that is yellow all over would be a nitrogen deficiency (most likely). If it's older leaves that are affected then I'm going to need to see pics for certain. My guess is with leaves turning white you'll need to do so repeat spray applications but the white leaves might not recover.

One thing that might also be important is that strawberries are really sensitive to salt levels so if you've salted to 1 ppt for the fish that might be part of the problem.

Get those pics if you can

Hi Scotty

Thanks for the quick reply. Here are some pics you requested. I havent added any sodium to the system but as for other mineral salts I added the epsom salt (maybe 1/4 cup total) I also put in two bottles of my ionic sulfate minerals. Good to treat 500 gal of which I have roughly 1200 gal in the system I think. These minerals are high in iron so I didnt want to use alot to make sure I didnt over do it.

I did just go and load up a sprayer with the high iron minerals so we will se what happens in the next couple days. Notice in the pics that the tips of some of the leaves have turned back green so I will just keep it up and wait for now. Tell me what ya think of the pics. The basil is showing some yellow but not half as bad as the strawberries.

I also have some cauliflower plants that just dont seem to want to grow. I have them in the CF bed so maybe thats why?

Thanks again

Chad

Hi Scotty

I did take another look at the minerals I put in the system and there is some sodium. In the pic below you can see that there is 15ppm in the solution but when mixed at 1000/1 as recommended that should be at .0154ppm right? Right now or abt two weeks ago was when I added the last bottle and only at roughly half of the recommended 1000/1.

Do you think the sodium in this stuff could be a problem for the strawberries? At this point im not going to take the chance and will stop the spray and order the chelated iron I found online today.

Thanks again

Chad

OK, so what you are seeing is interveinal chlorosis. Basically the veins are dark green but the areas between turn yellow. Some nutrients are mobile within a plant and some aren't. Iron is one of those that isn't mobile. It's tough to tell on the strawberries but based on the basil plant it looks like the older leaves are the affected leaves - so it's not an iron deficiency.

Seems like it's more likely root rot, a magnesium deficiency or a toxicity reaction.

First thing I'd do is pull a plant or two and check the condition of the roots.

Second thing would be to hold off on adding the fertilizer (or any other nutrient other than what the fish food gives.

While it could be a magnesium deficiency, I don't think it is because the leaves just don't look quite like I'd expect so I'd hold off on spraying epsom salts for at least a week.

The thought occurred to me that temperature may be a contributing factor but that's only a thought at this point.

I agree that they are probably dying and you may have to pull the strawberry plants before we get this figured out but I'd at least leave the basil plant in just to figure out what's going on.

I don't think that's enough sodium to really cause this problem and I don't think this is what you'd see if there was too much sodium in the solution. I think you'd see more tip burn if it was sodium.

Hope this helps

Hi Scotty

Ok I will hold off on spraying. I am sending some shots of the roots cuz it dont look like root rot even though some do have some fish poop stuck to them. Seems like just around 5 weeks being in the GB wouldnt be enuf time to get root rot any way but im no horticulturist LOL I do have two other basil plants in a different CF bed that are right next to each other and while one is showing almost the same yellowing as the one in the pic I sent. The other looks relatively fine.

I should also probably mention that I have a few tubs of duckweed set up in the system as well. The tubs act as a swirl filter of sorts. (not intentionally but noticed the fish poop accumulating nicely) The duckweed is doing great if that means anything.

What kind of filtration and grow beds do have on that system Chad? I'm seeing these plants in a DWC unit and wondering if the solids are smothering the roots. Suspended solids will do that to plants in a DWC system. Eventually without removing the suspended solids the roots will die and so will the plant.

The order of flow could be important on the filtration question so let me know how you've got it setup

Hi Scotty

Right now I have three grow beds. Two are the DWC or what I know as Constant Flow. No media just a flow of about 6-7 liters per minute. The third is a Flood and drain bed that I had to stop for a few months due to my clay balls disintegrating. Since the Hydroton is almost twice the price it is in the US or anywhere else because of the import tariff here I had a local pottery maker fire clay balls I had my workers roll. Turned out some werent fired good enuf so I had to have them all refired to be safe. I just got it back up and running a couple weeks ago but has no plants yet. I did manage to find some worms to throw in it but could use 100 more to get the break down of the solids going better. Cant just go to the convenience and buy worms for fishing like I did in Michigan LOL.

Anyway my filtration is just in my duck weed tubs I set up a couple months ago. I didnt do it intentionally but the flow is so slow through them I noticed they were picking up solids very well. I dont see much getting back to the fish pond but did notice that the two buffer bags I put in the pond collect a bunch as well. When I had the tomato plants going I checked the roots regular to see if the solide were building up and didnt see much at all. And there wasnt but a couple of the strawberry plants that had a little build up on the roots.

Lets just say that is the problem and I need to filter the water before it hits the beds with no media. Is there an easy way to do that by maybe putting a fine mesh sock on the inlet or will I need to go more technical and build a bigger swirl filter and only use the filtered water for those beds?

Maybe tomorrow I will take out one of the sheets of styrofoam and see just how much solids are in those beds to get a better idea.

As for the build the water goes from the pond to all the beds on the same supply. It hits the duckweed tubs first but is only a T on the way to the first DWC bed and on to the other two only supplied off a T in the line. Essentially they are all getting the same water from the pond and the only thing taking solids out is the duck weed tubs.

Thanks for the help buddy.

Chad

I'm new to aquaponics , but well versed in growing plants , I'd reckon your strawberries are suffering nutrient deficiencies due to the high pH .



Iron , manganese boron , copper and zinc , others as well . Try foliar feeding with a complete soluble fertiliser . repeat weekly or maybe twice a week . Spray a weak solution over the leaves , it will be absorbed through the stomates and be readily used by the plants . Whether the strawberries recover will depend on how stunted they are = too stunted no recovery .

Growing plants in the wrong pH is hard work .

Hmm, pH isn't really that high, from the first post, it's 6.8 which is about as good as it gets in AP .

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For the suspended solids one way to go is a Static Upflow Filter using plastic bottle caps some other floating media or Kaldness media. The layer of media floats at the top of the container and all the water has to pass through this. You can change the size of the media or the thickness of the media layer to adjust what passes through. This would go after your Swirl filter. The swirl filter gets the settleable solids and the SUF gets the suspended solids. What passes through both of these are the dissolved solids (ions and such).

Another way to go is to put a large enough media grow bed in the flow before the DWC. Grow beds trap solids and do this mineralization for you as long as you don't overwhelm them with solids. Having said this they apparently aren't great at catching suspended solids but they are apparently good enough and some here do use them for prefiltering water going to the DWC with success.

You can also use a stainless steel sieve or a Drum filter.

Unless you use the grow bed method, there is one other issue that you may have to deal with because of removing solids and that's nutrient deficiencies. It's a good idea to collect the solids in a mineralizer to break down the solids into dissolved nutrients which can then go into the DWC. Probably the easiest mineralizer is just a container with the solids under heavy aeration. Once the solids break down you turn off the air and let the solids settle and put the liquid portion back through the SUF.

[quote="scotty435"]Hmm, pH isn't really that high, from the first post, it's 6.8 which is about as good as it gets in AP

Crikeys ! ya right , I must be dislextic and read it as 8.6

I catch myself doing that sometimes as well - it's either that or I'm skimming and totally miss something I should have seen .

Cheers

Ok I think I have a decent quick fix in building a 10 gal swirl filter for each of the two DWC beds before the water enters the beds. My only concern is a potential reduction of flow to those beds. It might not be an issue since I will be using 1" pipe so my next question is. What would be the optimal flow rate to a 4'X8'X1' deep DWC bed? Right now its flowing at 6-7 ltrs per minute. Is that enough? If I am using a slower rate to keep the solids accumulating in the filter well. What would be the lowest flow rate that would be sufficient? I do have a 14" wand air difuser going in them as well so I am pretty sure circulation is good.

Thanks again guys. I probably wont save all the strawberry plants but the good thing is I can throw some of the runners in some soil while I get this sorted.

Chad

Chad, before you build those Swirl filters you may want to look at Radial Flow Filters instead or if you're willing to flush the filter every few days just use a Static Upflow Filter. Either of these will do a better job of taking out the settleable solids than the Swirl Filter will and the Static Upflow Filter will also take out a lot of the suspended solids. You could also combine a swirl filter with a SUF - I've got a couple of 20 gallon setups with 5 gallon buckets inside with the floating media - the water goes in and around the inner 5 gallon bucket (the swirl part), down to the bottom and back up through the media (the SUF) before it exits (not much more difficult than just making a swirl filter. The inner bucket is screened as is the outlet to keep the media in). For the DWC you really need to clear out some of those suspended solids, not just the settleable ones.

To answer your question (in the event the filters are already done) - What I've heard is that the water in the DWC needs to be pumped somewhere from once every hour to once every 4 hours (it's probably better to change it closer to once every hour from what I've heard around here).

Ok great Scotty. I do think that would be the better option. Could you send a couple pics or a link to show me what you got? I did do the math on what the current flow I have and could probably step it up a bit but right now Im pumping roughly 360 liters an hour through the DWC that is roughly 700 liters so its changing every two hours which isnt bad. Having said that. The way I have the pump set up I need to build the poop filters to be set just before the DWC supply line. Do you think I can get a flow through the filter that will match at least the flow rate I have now or am I looking at a total redesign of my supply system?