Backyard Aquaponics
A place to discuss aquaponics

Hi. I build this AP 2 years ago. My first system was a 50 gal FT with a 3'x7' constant flooded bed with 3 gal pots filled with volcanic rocks.
Huracaine Maria broke it so I decided to build a bigger system.
For this one mark a 12'x12' space in the back yard.
Start diggind a hole for the sump tank, after several days of hitting hard rocks change the idea of using an IBC for ST and just used a 55 gal drum, about 3/4 under the ground.

The FT is an 400 gal IBC. Filter system are two media beds filled with 10" with lava rocks and 2" with expanded clay clay for a total of 12" of media. Each media bead measure 3'x4'.
Each media bed gravity feeds to a 3'x7' raft.
System was designed so if I had to give maintenance to one side, (left or right) the system will be continued operating at the other side.

then constructed an 10'x10' pergola around it.

Filled with city water and ran for 2 or 3 days. After correcting leakage and Cl evaporates, I trow 4 small gold fish... and pee!
After a week ammonia went to 0 ppm so I trow 6 tilapia I had from my old system and put parsley that I bought as micro greens so I have live plants absorbing N and other nutrients. I also used water and media from my old system so maybe that is why it cycle so fast. Plants went huge. Mezclun, chilly peppers, tomatoes, all plants went huge!!!
It was so well, that after time I forgot to supplement at all, also to take measurements. Food was overproducing to me!
then, the system crashed!
...to be continued in next post.

Welcome to the forum Homar

some picture of the system late 2018 early 2019

December 2019 all plants start to die... I thought it was a passion fruit plant that over grow on the top of the pergola providing to much shadow. With pain in my heart I remove the passion fruit plant. but all plants continue to die one at a time until in feb 2020, all plants die except the chilly peppers! Strawberry, lettuce, even the spearmint die!

So take the dust out of the API kit, PH were yellow 6.0!
remove all the dead and old plants, start planting lettuce and adding CaCO3 once a week, but PH still bright yellow 6.0 !! After having hard time making plants to grow well. Start reading forums again as i was the first day!
add kelp once a week and finally some violet lettuce decide to grow!
some seeds of the old chilly pepper plant decide to grow by themselves so I let them just to see something green!
Start supplementing with some nutrients and minerals but the mezclum and lettuce i planted in the raft are week, parsley never sprout, coriander are thin and weak.
but tomato plants seem doing good.
feb is gone, march is gone, and PH still at 6.0 yellow. that told me that may be it were lower than that, may be at 5 or 4!
so start reading again for other alternatives to raise PH without overdosing with Ca to avoid nutrient lock, and found some people are using CaCO3 with KhCO3. every person at every forum use different rates and mixes. Knowing that you can mess very bad if not using the proper rates. keep looking for answers until found hydrobuddy last week!
because I had tomatoes I push hydro buddy for K,Ca,Mg rate of 3,2,1

KHCO3 – 5.8 g
CaCO3 – 12.6 g
MgSO4 – 7.7 g

4/14/20
after 3 days dosing those salts every morning, finally PH were at 6.4! so throw the same salts at same quantities again.
4/15/20
morning PH was at 6.4 Again. so throw salts again. At mid day, I read PH... it was stock at 6.4
so I trow 3 full spoons of Potassium bicarbonate!!!! after 5 hrs, PH still at 6.4!!!!!
4/16/20
6.4 again in the morning, added salts. At mid day, still at 6.4 so re dose again with 1 spoon of Mag Sulfate and 1 spoon of Potassium Bicarbonate. 1 hr later, still at 6.4
I was using just one spoon of Calcium carbonate during about 3 weeks, that’s why I think is not wrong to just use K every other day with Mg to avoid unbalance.
I am sharing my experience so the new can learn from my testimony and mistakes, and the old maybe can evaluate the pictures and tell me what is wrong, what can I do different, or if all I need to do is keeping adding buffers a little at a time until finally PH is raised.
My conclusion last week was that because the PH went lower than 5, healthy bacteria start dying then plants start dying too.
Ammonia each morning is at .5 ppm and nitrites 0 ppm. If i pee the night before, ammonia next morning is at 1 ppm and nitrites from 0 to 10 ppm.

Aquaponics 101
1. Álways check your PH, Amonia and nitrates
2. when something is wrong with a plant grow or have to many deficiencies, check plant roots!!!!

results than in both my raft beds where fish eating the roots!!! thats why some plants where growing thin and week or not growing at all!!!

Nice looking system. Sorry to hear about the plant problems. I didn't notice that you mentioned what kind of fish you're growing?

Watch the feeding for awhile, sometimes the low pH can kill the bacteria handling bio-filtration, that can cause ammonia or nitrite levels to go up. Fish generally aren't too wild about the low pH either. The other thing is that the new higher pH causes the ammonia to be more toxic.

Cheers

thanks for the inputs
yes, I think the low PH may have kill a lot of bacteria, thats why almost all plants start dying December 2019 excepts the ones with big root system.
My system were over producing food so I was not checking parameters for about a whole year!
Sometimes I refilled with rain water, that contributes to the low PH,
also.... sometimes I refill directly from tap water. may be that contribute in the killing bacteria.
my total system is about 600 gallos of water so I thought 25 gal of refill per day directly from city water will not hurt...
350 gal FT
25 gal to 50 gal in the sump tank
25 to 50 gal in each media bet
about 50 gal or more in each raft bed


I have about 25 tilapia taken from a river, with about 5 unknown fishes that got in the buckets when fishing the tilapias

Once a system has aged and has built up some organic matter it should be fine with additions of up to 20% of total system volume using chlorinated water but I wouldn't do any more than this. You'll lose some bacteria when you do a water change with chlorinated water but I've done this many times without any apparent effect on waste processing. I think new systems should probably avoid this type of water change for about the first 6 months while they build up some organic matter but I can't say for certain at what point a safe level would be reached - it may be sooner or later and smaller amounts of chlorinated water during the build up may be fine, there are a lot of variables .

Pictures of the sad plants and roots eaten by a small devil fish, I throw the bastard to the chickens!

Glad you figured out the cause anyway. Slightly off topic but what program did you use to make that drawing in your 1st pic?

Autocad. I have limited space. So I draw everything first, then start playing around with wood or recycled stuff, re do the drawings, until got the final version, besides the aquaponic, I have a 8' x 40'chicken fence, a monkey bar, a climb rope, brick oven pig size! so I have to drawing and plan ahead before construct

to calculate de amount of salts I use hydrobuddy. I wanted to use small amount of salts per day, so I start with 10 gal in the "Volume" input, and increase it 5 gal per day the last few days to increase the amount of salts.
today I use 30 gal in the volume input and the result was 8.7 g of Potassium Bi Carbonate, 18.9 g of Calcium Carbonate, and 11.5g of Magnesium Sulfate for a rate 3-2-1 of K-Ca-Mg (more K than Ca because of the tomatoes)
last year I was using CanaStat but that spread sheet dont have CaCo3 listed

Hello,
I am running into the same kind of issue with my year old system right now. I have a PH thats hovering around 6.I am testing with the API kit, and a low PH strip test.

The interesting thing is that I have been gradually adding Calcium Carbonate and Potassium bicarbonate over the last few days, but the ph isn't changing much, if at all. I've added about 5 tablespoons of the calcium, and about two tablespoons of the potassium.

The system has about 400 gallons in it right now, and we recently had some good rains, which also might have lowered the Ph, along with the system's maturity. I have been keeping shell grit in a bag for about 7 months, but am not sure about the effect of this.

Plant growth doesn't seem affected right now, but today the ammonia was a bit high.

Now, here's the fun part, I tested the general hardness and carbonate hardness, which I don't really understand. The GH was at 22, and the KH was at 27, or this is how many drops of solution it took to get a color change. . I thought I thought I read somewhere that they should be around 4, but maybe this is ok???
I am wondering if this can get too high?? And also, I salted the system about two months ago, to about 2 or 3 ppt, so I am wondering if this has anything to do with the high numbers.

The calculator that you are using is interesting, I didn't know that those existed!

I only add a little pinch of sea salt every other day.
but have not measure hardness yet

I took me about 3 weeks to finally raise PH adding the amounts mentioned before at a rate of 3-2-1 because I have tomatoes

it is important to keep a good ratio between K-Ca-Mg to avoid nutrient lock

this is the amount I was using daily until reach 6.6 then every time it drops to 6.4
it is not good to raise ph drastically, i loss some tilapia s couple of years ago when first learning about aquaponics
also plants tend to show deficiencies when only adding CaCo3, may be because of the imbalance of nutrients

plants like acid so at first you will not see damage to plants, but with time good bacteria will be killed resulting in ammonia spike, less N, less available nutrients, more solids, then the plant will start to die
I learned the hard way

Question.
is it ok to pee in the sumptank every other day to increase Nitrates?

plants seems better since star paying attention to the system.
but PH still dropping every week to 6 or lower
Use the salifert kits to test fot nutrients, these were the results
N - 10 ppm
P - 1 ppm
K - 150 ppm
Ca - 75 ppm
Mg - from 0 to 30 (kit only measure from 30 ppm or higher, not below)

I just add 230g of magnesium sulfate, according to hydro buddy, it will raise Mg ppm to 15
tomorrow I will add 230 g more to raise it to 30 ppm

so, these is my new query..
How to keep the PH between 6.4 and 6.6 where I want it, without using CaC03 and P2CO3????
question number 2:
what are the safest higher levels of Ca and K in an aquaponics system?

the quest for a balanced and happy system continues.....