Stuppy Aquaponics Blog

System Update 4/26/17: Frasier

Posted by Conor Quinlan on Apr 26, 2017 2:30:00 PM



Nitrogen (mg/L)






Total Ammonia




Temp (Fo)



EC (mS)



















04/24/17 -> Total Hardness: 350-360 mg/L CaCO3 equ
Calcium Level: 64 mg/L  Magnesium level: ~48 mg/L
Phosphate Level: ~ 25-30 mg/L (as PO4-)

Water Quality Overview: 

Nitrate levels are remaining constant while total hardness and EC are falling slightly. This is most likely due to the large addition of 45 gallons of source water on 4/23. It is significant enough to assume the system has reached the peak production capacity for now. The level of crops that can be supported in the system is more than we expected for the current feeding rate of 120 grams per day.

The pH is finally beginning to drop significantly with alkalinity levels dropping. Even with the addition of the source water(which has a higher pH levelof 8) the pH still managed to drop significantly. It shouldn’t be much longer that K2CO3 can be added to help raise the K levels.

The addition of the 700 grams of kelp powderhas made a significant difference in the concentration of trace nutrients. We have shipped out a water sample to see the concentration of all nutrients and compare them against our previous sample from 2 months ago. 

Fish Update:

The fish are doing well but with slower growth than anticipated. It is apparent now that the source of the fish is the source of the problem. The high quality tilapia recently added to the second system are feeding and growing better, already consuming slightly over 4% body weight.

The feeding rate for the Niles system is now at 120 grams/day. This is enough to sustain the crops in the system with a couple additions to correct the trace nutrient concentrations and increase K and P levels. It is quite surprising that the crops can be sustained on such a low feed amount. Tomatoes and cucumbers are still unable to pass seedling stage, suffering severe deficiencies, It will be some time until they can be added to the system. A lack of K seems to be the main source of the deficiencies.

In the first image below you can see what the fish tank looked like on 4/17 and in the second what it looked like on 4/24. The water has cleared up considerable since adding the kelp power which quickly dissolved nutrients into the system within the matter of a couple days.

Fish on 4_17, Water is dark with kelp powderFish on 4_24, water has cleared significantly


Crop Update:

We have seen great improvements since the addition of the kelp powder. All previous trace nutrient deficiencies on the bean crops are nearly gone and even the K deficiency has let up quite a bit. 


Since the addition of 50 grams of super triple phosphate the growth of the strawberry crops also appears to have improved immensely. Nearly 75% of our strawberries now have flowers and some are even beginning to form fruit already.  The lower humidity since 4/19 (<50% humidity, 35% average) is causing some cracking on the lower ends of the beans but other than that they look very healthy. The humidity doesn’t appear to be affect any other crops in the system right now. 

wide angle view of Frasier system

You can see a dramatic change is strawberry crop size from 4/17  -> 4/24 . No more crops have died since our initial planting, a very good sign. 


Below is an image of the flowers that are being seen on many of the strawberry crops. All of the varieties appear to be doing well. The Earlyglow and the Sparkle are doing much better, even better than the Cabot variety which is now showing some Ca deficiency due to transpiration problems.

The peas are also flowering heavily and should be producing fruit very soon.


Topics: Aquaponics, Plants, Fish