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Will this Dosatron do the job?

Discussion in 'Growing Areas' started by Armando, Dec 23, 2008.

  1. Armando

    Armando Hobbyist gone wild

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    Trying to find a fertilizer doser that will not break the bank!

    I found this Dosatron model that is less expensive than the super-duper models. Is this something I can use? I would hate to buy something that is "cheap" but won't meet my needs (24x16 GH).

    http://www.ofe-intl.com/detail_display.asp?productno=DOS 007F

    TIA!
     
  2. Jon

    Jon Mmmm... bulbophyllum...

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    I suppose it depends on how much water you usually use. Do you have any idea?
     
  3. Armando

    Armando Hobbyist gone wild

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    I don't have a number for that, i'd say i'll be fertilizing the plants once a week on a 24x16 area. On their site they say "Ideal for Smaller Home Greenhouses" so i think it should be OK?
     
  4. Jon

    Jon Mmmm... bulbophyllum...

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    The reason I ask is that this is rated up to 7 GPM. The comment about smaller home greenhouses is relatively ambiguous. 24x16 isn't very small, though.

    Most GH sprinklers have flow ratings. If you take the number of heads and multiply it by the flow rate of each, you'll have a decent idea of how much water you're using per minute.

    Personally, I would recommend looking into a Chemilizer. It's about $20 more, and you can have up to 13 GPM (almost twice that of the Dosatron you referenced).

    Hope that helps.
     
  5. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    I don't think the size of your greenhouse is the issue. I think it will depend on your water flow. I think they are rated at gallons per minute, and water pressure my also be an issue. You can test your flow by timing how long it takes to fill a 5 gallon container. The higher the volume, the faster the greenhouse gets watered, so don't plan on lowering your water volume while you water, you'll regret it.
     
  6. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Jon's point about higher gpm is a good one. So check what your actual gpm is. With my plumbing, I could never get 13 gallons per minute. I don't know Chemilizer, but am very satisfied with the Dosatrons I have.
     
  7. T&J San Antonio

    T&J San Antonio New Member

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    I think it kind of matters how you water. If you use sprinkler heads, then the GPM will be a factor. On the other hand if you hand water you need to find out what the least amount of pressure it will work on. As far as the ratios go, they are adiquate.

    Now then if water pressure is indeed a problem you may want to get a seperate pump to supply your doseatron. Some years ago I changed over to R-O water. Not totally R-O but a 20% mix of city water with 80% R-O water. I have a 90 gallon per day R-O system and I have it set to fill two 55 gallon plastic drums to an 80% mark. Then I fill both barrels up with city water and pump the mixture through my watering system with a seperate electric pump bought from Sears and designed for irrigating systems. Through a system of bypas valves I can regulate the pressure from the pump to a desired pressure setting and I get a good mix of my fertilizer. I know to some it may seem a little bit overboard but it works for me. Our water has a high calcium content and if I use straight city water, it coats the leaves and the walls with a calcium build up that is unsightly. By reducing the city water content, I have very little build up of calcium.

    just tom
     
  8. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Are you saying that the pressure going into your injector pump affects the concentration of fertilizer at hose end?

    I also use RO water with a shallow well pump to bring it out of my holding tanks. Before I replaced my very old, sad pump a few months back, I was only getting about 35 psi. With the new pump I have 60 psi and there is no difference in the hose end product.
     
  9. Forrest

    Forrest Really Neat

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    there should be no difference based on pressure with this level of product. They are designed to deliver even amounts of chemicals per measure of water.

    The ones that are affected by pressure and stopping and starting is the syphon types.
     
  10. Jon

    Jon Mmmm... bulbophyllum...

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    Pressure only becomes an issue if it falls outside of the stated 7-70PSI range.
     
  11. Ray

    Ray Orchid Iconoclast Supporting Member

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    Agreed, and it is likely you will not exceed the flow rate either. A simple way to check is to time the filling of a 5-gallon bucket.

    One thing I would recommend is increasing the ratio to 100:1 from the preset 200:1. With some fertilizers, particularly those containing decent levels of calcium and magnesium, precipitation can be an issue.

    For example, if you use the MSU RO formula and want 125 ppm N, you need to add 3.55g of fertilizer per gallon of final solution. At 200:1, that's 710 grams (1.56#) per gallon of concentrate, and even though the "practical solubility limit" is 2#/gallon (according to Bill Argo), you're getting close enough that there will be precipitation over time. I have my metering pump set at 100:1, and still keep a submersible pump in the tank, circulating the solution 24/7, just to be sure it's all dissolved.
     
  12. Bob2741

    Bob2741 New Member

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  13. Bob2741

    Bob2741 New Member

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    Tom is never overkill its called experiementation