1. The Practical Aquaponics discussion forum has been in operation for the last 5 years...

    We have enjoyed giving this service free of charge however ongoing increasing financial costs of running this service is making it increasingly difficult. Up until now we have resisted advertising as a means of a revenue stream to help run this forum but it has become inevitable that extra revenue is required to run this forum.

    We have introduced a donate button to help offset the cost of running this forum. It is completely voluntary, but if you would like to donate, all donations would be greatly appreciated.

    Thanks Murray..
    Dismiss Notice

Nube. First AP system, water chemistry issues

Discussion in 'New Aquaponics systems - DIY' started by Oliver Villis, Aug 12, 2021.

  1. Oliver Villis

    Oliver Villis New Member

    Aug 11, 2021
    South Australia
    Christies Beach
    Hi Everyone,

    First post, and I'm very new to aquaponics and quite ignorant about water quality. I just recently started up my first system about 2.5 months ago. The system includes an 18 square meter DWC bed (with aeration), 3 square meters of lava rock media beds with auto syphons. 2 x 1000 L IBC fish tanks, and 600 L sump. I guess that's about 5000L in total.

    *Thanks in advance :), if anyone can suggest how to adjust the water parameters, particularly to correct the imbalance (see images).

    Problem 1

    I am struggling to understand how water chemistry works. I have been reading up, but still not understanding. My start-up plants (mostly Bok Choi and Mustard Green) seem to be growing quite fast, but I'm pretty sure they have a nutrient deficiency. About 30-40% of the plants have a mottled yellowing on the leaves between the veins. However, the rest of the plants look pretty ok to me. I'm not sure what the deficiency is or how to correct it.

    After the ammonia and nitrite cycled down to zero with the help of some nitrifying bacteria, I added about 50 small to mid goldfish to get started, then waited a bit a bit and added 100 very small silver perch (30mm).

    I guessed the fish would not be producing enough nutrients, so I have been supplementing with the following; chelated Iron, calcium carbonate, potassium carbonate, Epsom salt and power feed (seaweed and fish emulsion), plus a little bit of bicarbonate of soda when the pH was dropping too fast. I have also been adding some ammonia.

    Problem 2
    I'm sorry to say 25 of the baby silver perch died in the first couple days. a week later, the rest seem ok. hopefully the rest will forgive me,

    Water Parameter

    The water parameters seem out of balance, based on what I have been reading. But I don't really understand how to adjust them, without raising the General Hardness, which seems way too high. The KH also seems way too low.

    My Test Kit Reading
    Water Temp; 18c Day / down to 14c at Night (middle of winter in Adelaide)
    pH; 6.5 (was slipping down a lot but seems to have just started stabilizing).
    KH: colour change after 2 drops (35.8 ppm, according to the chart)
    GH: colour change after 12 drops (214.8 ppm, according to the chart)
    Iron: 0.4
    Calcium: 125ppm, (I think, but not sure if I have read the test kit correctly)
    Ammonia: 0
    Nitrite: 0
    Nitrate: 160ppm (or more, its at the end of the test colour chart)
    EC: 1.0
    Potassium: (Not sure how to test, any suggestions on how to test?)
    Magnesium: (Not sure how to test, any suggestions on how to test?)

    Attached Files:

    Last edited: Aug 12, 2021
  2. Murray

    Murray Site Admin Staff Member

    Jun 4, 2009
    Hi Oliver,
    I hope you have sorted your system and the fish are doing ok. By now they should be a good size.

Share This Page