Aquaponics system updated week 13

Week 13

Hello Steemit! Have a tasty minty green drink from my garden. I had to do some growbed cleaning mostly removal of mint, it grows like crazy. I set up an extra ibc for easy nutrient solution mixing and topping up evaporated water. Also the fish ate a lot this week. Thank god it rained.

Mojito

Nutes in ppm

This week was all about nutrients, the fish raised the nitrates 70 ppm in one week, I also added 180 gr of epsom salt, 50 ml of 75% orthophosphoric acid, 160 ml of 25% potassium hydroxide in one go.

Element	My values	Typical hydroponic solution
N	80	210
P	>20	31
K	45	235
Ca	140	200
Mg	40 - 50	48
Fe	0.6	1 to 5
Cu	0	0.05
NO2	0.1	0

At this point I'm forced to add too much phosphor in order to neutralize the kaliumhydroxide. So the H3PO4 and KOH combo isn't working too well. I'm thinking either getting sulfuric acid or a different potassium source could give more control. This was also the first time Calcium dropped, it had been raising steadily throughout the season. Maybe the tomatoes starting to set. At this feeding rate I have to add about 25 ml of the KOH solution daily to maintain the ph at 6.8. I managed to keep it between 6.6 and 7 this week.

The nitrate increase had some interesting effect on my tomatoes, notice the first spindly growth and then much thicker stalk
tomato in aquaponics

Micronutrients

In light of my previous post, having learned that zinc and copper are added through the fishfeed in sufficient quantities, I stopped adding zinc and copper chelates. I'm still adding iron, boron, manganese and molybdenum in small quantities. Happy to have bought these all separately.

I find it strange the people at the uvi system reported very low values of boron, manganese and molybdenum after running their system for 4 years but they didn't start adding them. In general people are only adding iron chelates because otherwise you get clear deficiency signs in aquaponics (yellow leafs green nerves). My biggest cost in adding these is time, but with a diluted solution I just have to add a syringe and not lose time measuring.

Macronutrients

In the same interest of reducing the time I spend, when adding macronutrients I've set up this ibc. I can safely mix my nutes there not worrying about the fish. My main concern now is not introducing ph swings to the system. It will also come in handy in hot weeks when it doesn't rain and I have to add water to compensate evaporation, that's about 20 liters per day.

Harvesting

This time harvesting was more of a cleanup operation cutting back the mint and watercress.
I made syrup with the mint and used that to make myself a mojito :). I've decided to give the beetroots one more week as they started to grow again.

mint	beetroot

Looking out for

fish starting to get big >200gr	how much longer?

I could use some help on ideas on what to do with the space that will be freed by the beetroots. Spinach? in the middle of summer. I guess lettuce is starting to look unavoidable. Something fast growing. Maybe cucumber.