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Advice on automated dosing of various products wanted

Discussion in 'General Plant Topics' started by Gilles, Apr 6, 2010.

  1. Gilles

    Gilles Lifetime Members
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    For a heavily planted 500 liter tank with KH2 and PH @ 6.5 i would like to have some advice on the dosing.
    I only have 4 dosing pumps, and i would like to automate my dosing as much as possible, being it on a 'lean basis' as in: not over-dosing.
    I weekly change 20-30% of my water with KH2 water.

    So this leaves me with:
    container 1: Flourish Excel
    container 2: KNO3 / 10ml adds 1ppm @ 500 liter
    container 3: KH2PO4 / 10ml adds 0.1ppm @ 500 liter
    container 4: plant mix*

    The plant mix consists of:
    - Flourish
    - Flourish Trace
    - Flourish Iron (or Ferrous Gluconate equivalent)

    So, based upon the Seachem site, i can safely mix those together, in a ratio of:
    - Flourish: 40ml/week
    - Flourish Trace: 65ml/week
    - Flourish Iron: 15ml/week (giving 0.26ppm iron)

    My questions are (based upon a heavily planted tank):
    1) Is this a good ratio/dosage?
    2) How much of KNO3/PO4 should i add daily or every other day to begin with?

    Thanx
    Gilles
     
  2. dutchy

    dutchy Plant Guru Team
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    Hi Gilles,

    Maybe I can help you a little bit on the second question: My tank is heavily planted 600 liters and 0,5 Watts per liter of light. It uses around 5 ppm of KNO3 and 0,5 ppm of KH2PO4 per day.

    regards,
    dutchy
     
  3. jonny_ftm

    jonny_ftm Guru Class Expert

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    Dosing EI for NO3 and PO4 would be the best you can do in my opinion. At least you're sure you don't lack nutrients.

    50%WC is a no way for you? If no, you could try decrease the dosing by 30% once things are ok

    Your PO4 stock solution is too light, you'll need too much liquid to add the needed PO4. 0.1ppm PO4 is really low, I target above 1ppm, EI even 4x this
     
  4. Gilles

    Gilles Lifetime Members
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    Well, doing a 50% WC involves me to gather 250 liters of reverse osmosis water, which runs in the papers ;)

    But anyway; Lets say i consider using EI; and converting the required dosage per day for my tanksize, this would give me the following dosage requirements:

    Potassium Nitrate - 40g to 500ml of water and adding 10ml per 100L of water would give you a value of 5ppm.
    70ml solution or 1 1/2 tsp KNO3 3x a week = 105ppm/week
    Splitting this in 7 days gives 10,5ppm/day

    Potassium Phosphate - 15g to 500ml of water and adding 5ml per 100L of water would give you a value of 1ppm.
    40ml solution or 1/2 tsp KH2PO4 3x a week = 24ppm/week
    Splitting this in 7 days gives 3ppm/day

    Since i have 500ml bottles, and i would like to 'refill' my bottles 2 weekly; e.g. 14 days; it would all mean that i have to 'use' 35mls / day.

    If i enter these values on my own calculator;
    - 500 liters net.
    - 500 ml stock
    - 35 ml/dose
    - 10.5ppm NO3 per dose => 123 grams KNO3 in 500ml water
    - 3.0ppm PO4 per dose => 30.71 grams PO4 in 500ml water
    - 5.0ppm SO4 per dose => nothing required to hit 5ppm K2SO4 (stock allready contains 7.86ppm)

    So i don't know the maximum grams you can dillute in water, but i think 123 is to much and can't be dilluted. What do you think?
     
  5. dutchy

    dutchy Plant Guru Team
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    The most KNO3 can be dissolved in 500 ml of water is 425 grams. KH2PO4 is 75 grams.

    Regards,
    dutchy
     
  6. Gilles

    Gilles Lifetime Members
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    Does that involve a certain temperature you would require for that? It would be cool if i could incorporate this into my calculator.
     
  7. jonny_ftm

    jonny_ftm Guru Class Expert

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    Chucks calculator gives you the solubility. Also, you can use google for example: "CaCl2 solubility"... will give you a wikii page with all info

    Usually solubility is given for 20°C
    You have to dilute the total grams of KNO3 in a small quantity of hot water. Once diluted, you top it to the 500ml mark. That's the definition of solubility and the base of ppm calculations. Not add powder directly to 500ml or you end up with more than 500ml volume and less ppm/ml

    You can try less WC volume and lower dosing by 30% and see how it runs for you. Also, if you have low light, you can reduce dosing even more. By the way, a 500L tank will have usually around 350-370L (30% less or more, depends on tanks). But yes, still large volumes to deal with
     
    #7 jonny_ftm, Apr 6, 2010
    Last edited by a moderator: Apr 6, 2010
  8. Tug

    Tug Lifetime Charter Member
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    Not sure if this helps. But..

    NO3 daily uptake for non-limiting EI is about 4ppm with 100% uptake for heavily planted tanks. My daily dose is about 3.9ppm. Wet's calculator http://wet.biggiantnerds.com/ei/con_v_time.pl might help you decide if a lower dose with your water changes would work for you, but adding a daily dose closer to 4ppm would not harm fish and would give you something closer to the EI recommended dose .

    PO4 uptake at 100% is around 0.6ppm a day. Again people around here keep water around 2ppm with NO3 levels around 10ppm and up. Keep some distance between PO4 and NO3, about 1: 5 - a non-limiting dose is the goal, not so much the ratios.

    Plant mix is harder for me to say. I think you might save some money if you start using CSM+B. But, to finding the non-limiting amounts that work with your tank it is easier on the plants to start heavy and reduce your levels every two weeks until you find your "sweet spot". I did find this calculator http://www.fishfriend.com/fertfriend.html that would suggest your a little light on the levels of iron. Even PMDD suggests dosing 0.1ppm of iron daily.

    You do not mention any Ca or Mg levels, but if they are low you need to find a fix for dosing those weekly.

    On a side note - KNO3 can be added to your plant mix without causing any precipitates or add it to the KH2PO4 and add the Excel to the plant mix, to give you back two of your containers.
     
  9. Tom Barr

    Tom Barr Founder
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    If reduced water changes and leaner dosing is the ultimate goal:

    Start with higher non limiting % of dosing.
    Accept some higher % water changes until you slowly and progressively reduce the dosing cocnetrations.
    If you start with a limiting amount, you end up not addign just enough nutrients, you end up adding not enough to start with.

    Always start with a non limiting references, then incrementally reduce the ppm's slowly and carefully, watching the plants very closely.
    This assumes light and CO2 are independent.

    If light is at a lower intensity, then the lower ppm's are easier to achieve and reduced water changes are also possible.
    SAME FOR CO2 MANAGEMENT.

    So since your ultimate goal is less work I'd assume, I start with non limiting nutrients/CO2, then work with light as the starting point.
    Once you find the min light, then move to reducing the CO2.
    From there........now we can look at nutrients..........

    Now here's where you should really think and consider things: sediment sources vs water column dosing.
    Since reduced dosing and reduced water changes are a goal based on ppm's in the water column, using both sediment rich and water column lean dosing would be best to suit this goal.

    So something like ADA aqua soil + lean dosing, say 1ppm of NO3 and K+ and .4ppm or more of the PO4 daily.
    K+ and PO4, as well as NO3 can be very high and over a wide range, so if they climb, it's not hard to adjust and you have plenty of room to play with.
    Since growth is light limited anyway, then the nutrient demand is reduced, as well a sCO2.

    So the sediment can play a larger role and require even less dosing to the water column.
    Over time with most clay type sediments like ADA, N will be reduced quite dramatically comapred to the other nutrients.

    So adding more N with time will help.
    Another way to deal with this as a tank ages, is to simply add more fish and feeding.

    What happens if something goes wrong with the dosing pumps and it adds the entire container?
    Do you also use automated feeders for the fish or feed them daily?

    Dosing daily is easy as feeding the fish 2-3 things.
    Just make it convenient.


    Regards,
    Tom Barr
     
  10. Gilles

    Gilles Lifetime Members
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    Thanx for all the replys;

    So if i start by dosing;

    40ml of KNO3 (4ppm daily) spread over 4 times / day
    and
    40ml of PO4 (.4ppm daily) spread over 4 times / day

    and just see what that does?
     
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