Nitrate droped on the cycled system

[Kanratana Kok]

Dear All,

I got my aquaponics systems setup and system is cycled about 1 month and half now, i got a hybrid of EBB, DWC, and NFT integrated together.

My EBB is (40cm x 60cm), DWC (90cm x 120cm) x 2 beds (using 50 gallons barrel), NFT ( 2.5m x 3.5m ) grow area which capable to hold up to 170 plants.

Fish Tank 50 Gallons Barrels x 2 ( 100 Gallons in total ), total water in whole systems including Sump tank is about 300 Gallons

I got a total around 150 plants growing in whole systems (4 tomatos - setting flower and fruits, 4 cucumbers - setting flower and fruits starting, 5 Cabbage, 142 lettuce - 100 lettuce are adult size, and 42 are growing to be adult size)

Fish: 14 Tilapia about 3 finger size, 10 Crap fish about 2 finger size.

for the last 1 to 2 weeks i did the reading of the water test ( ammonia 0ppm, nitrite 0ppm, pH 7, nitrate 120ppm)

last few days since my tomato start to set small fruits about 10 of it i did test my water again yesterday and today the reading (ammonia 0ppm, nitrite 0ppm, pH 7, nitrate 5ppm), no matter i try to increase the feed to my fish it still didn't make any change to my nitrate level at all.

my question is there any up normal to my systems? and what is a good and optimum level for nitrate should i maintain, and at my current system Nitrate 5ppm is it going to make any problem to my plants?

and why my nitrate is drop is it cause by plants start to grow big? my density fish is not enough? please advise would be appreciate for anyone could help me to answer.

Thanks

Ratana

[Kenji Snow]

Looks like the plants are using all of it and your fish load cant keep up with the demand. 

[Rob Nash]

time for more fish and or less plants.. but really its all about the plants... are they still green and growing? if so you may be fine for now... but you may have to reduce the plants for now, and stop adding new ones until your fish get bigger.