Testing for Manganese in Aquaponics

Manganese is an essential micronutrient for plants, participating in several metabolic processes – mainly photosynthesis. Of course, an excess amount is toxic.

Deficiency symptoms can include: Interveinal chlorosis on older leaves, light green leaves with dead patches ringed in yellow, few flowers or fruit. Interveinal Chlorosis and few flowers/fruit can have many causes, so testing is recommended to determine actual deficiency.

Hoagland suggests a Manganese level of 0.5ppm. While higher than the PNEC_Aquatic of 0.246, a review of common Aquaponics organisms suggests that levels <1ppm should be safe.

Unless you have a colorimeter, your best bet is the SenSafe Manganese test strips. These aren’t normal test strips, but the directions are clear.

  1. Hanna HI38042 (0-3.0mg/l, .2mg/L) DISCONTINUED
  2. LaMotte 3588-02 (0.05,0.1,0.2, 0.4, 0.6, 0.8, 1.0)
  3. Hach MN-PAN (0.05 – 0.7; Resolution = 0.05)
    $179/50 = $3.58ea
  4. Hanna HI96709 Portable Photometer (0.0-20.0; Resolution .1)
    $183@TestEquipmentDept meter + $35.49/100 = $0.35ea
  5. LaMotte Smart3+3658-01-SC (0.0-0.7, MDL .01)
  6. Hach Colorimeter II Manganese LR (0.01 – 0.70; Resolution 0.01)
    $430meter + 50 tests. Uses 8149 Method.
    Hach_PCII_Manganese_LR + Hach8506
  7. Hach DR900 + 8149 (0.006 – 0.700; Resolution = .006)
    $51.95@Hach / 100 = $0.52ea
  8. SenSafe Manganese Test Strips (<0.02, 0.05, 0.1, 0.2, 0.5, 1.0, 2.0 ppm)
    $26.99@Amazon / 24 = $1.25ea

Know of a different or better way to test for Manganese in Aquaponics? Let me know in the comments and I’ll update this post.

2 thoughts on “Testing for Manganese in Aquaponics”

  1. It looks like the HI96709 is also discontinued. The two Manganese testers on Hanna’s site are the HI 96742 and the HI 96748. But they only measure 0 to 300 µg/L

    1. Thanks for the update on the HI96709. My recommendation is still the SenSafe Manganese Test Strips, unless you already own a multi parameter colorimeter (i.e. Hach DR900 or LaMotte Smart3)

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