Calcium low?

Discussion in 'Water Chemistry' started by Themuleous, 7 Nov 2007.

  1. Themuleous

    Themuleous Member

    Messages:
    4,126
    Location:
    Aston, Oxfordshire
    Recently I've noticed the plants in my mid light EI 20g high tank are lacking something, and given that the tank reads 3ppm PO4 and 30ppm NO3 right before the 50% water change I'm guessing it must be a micro of some kind.

    I did a bit of research but cant pin it down to a specific element. Anyway, it got me thinking about calcium so I tested the water and it came out at 4dGH, very soft. Could a GH as low as this cause a calcium deficiency? I've never really come across calcium before, I guess as its in the water its never really a problem.

    FYI in case you are interested, symptoms include misshapen leaves, stems going brown and breaking off half way, and lastly, the leaves loose all their green colour between the veins, get a good look at the vein structure but thats not quite the point I dont think!

    I'm using the AE trace which I note doesn't contain calcium or magnesium.

    Cheers all :)

    Sam
     
  2. Graeme Edwards

    Graeme Edwards Founder Staff Member

    Messages:
    1,161
    Location:
    Wirral/Chester Cheshire.
    Not sure calcium is what you should be worrying about. Seems a strange connetcion.
    I think, and it is a "think", if your leaf structure is failing,my first thought would be down to lack of potasium (K).If not (K) then possibly Iron, it the cause.
    Thats my forst thoughts any way mate. Do you dose (K) at all?
     
  3. Themuleous

    Themuleous Member

    Messages:
    4,126
    Location:
    Aston, Oxfordshire
    My other thought was K, so since last week Ive started adding extra K, 15ppm each dose, but its from the granule form from AE so not sure how accurate the dose is as its never dissolved 100%. But yeh adding extra K. I also doubled the trace dose so there is more iron, it cant hurt if it doesn't help.

    It is still early days on the increased K and trace dosing, but I have noticed the new leaves on the H.poly are in a much healthier state than previously so thats a good sign.

    One other question, any idea how long plants take to recover from a deficiency? Is it weeks or months, I guess it depends on many factors.

    Thanks for your thoughts Graeme :)

    Sam
     
  4. Graeme Edwards

    Graeme Edwards Founder Staff Member

    Messages:
    1,161
    Location:
    Wirral/Chester Cheshire.
    Stem plants will recover much faster (weeks) , just by thier very nature. Things like crypts and ferns will take much longer.

    Sounds like your (K) is the key mate.
     
  5. Themuleous

    Themuleous Member

    Messages:
    4,126
    Location:
    Aston, Oxfordshire
    Right oh, will keep up the extra K and see what happens.

    Thanks again

    Sam
     
  6. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi Sam,
    If you are dosing EI via dry goods then you are dosing about 3 or 4 times as much K than you need by the mere fact that you are dosing KNO3 and KH2PO4. If you suspect a calcium/magnesium problem and want to raise the GH then you can just add GH booster once a week and fix that right away.

    Typically, loss of green hints at a Nitrogen shortage while deterioration/stunting hints at a Carbon, Phosphorous and/or Nitrogen shortage.

    It wasn't really clear what the dosing scheme was although you mentioned "... the tank reads 3ppm PO4 and 30ppm NO3..." Is that from test kits or is that the amount you are adding per week?

    Frolicsome_Flora's magic calculator shows that 20 Imp gallon needs 1/4 tsp KNO3 and 1/16 tsp KH2PO4 3 times a week and 3/32 tsp CSM+B twice a week. If the tank is strongly lit and is heavily planted then you could easily dose twice these amounts.

    If you are adjusting your dosages only based on what you measure with test kits then you could be perfectly accurate one week and then way off the next. If the dosing is OK then have a look at the CO2/flow.

    If you prefer the sniper rifle to the shot gun and you want to zoom in on the specific deficiency then you'd have to make the dosing change and wait about 2 to 3 weeks to see the effects on stem plants. As Graeme said, crypts, ferns, mosses and the like take much longer because they are slower growing.

    Cheers,
     
  7. Themuleous

    Themuleous Member

    Messages:
    4,126
    Location:
    Aston, Oxfordshire
    Thanks for the advice. The tank is EI, with each dose being 15ppm NO3, 1.5ppm PO4 and 15ppm K. 20ml AE trace.

    Those test results were from test kit readings taken immediately before the 50% water change.

    I thought K was unlikely but it doesn't hurt to increase the level a bit. So I upped this and Fe at the same time, to be sure the plants get all they need.

    Sam
     

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