1. The Practical Aquaponics discussion forum has been in operation for the last 5 years...

    We have enjoyed giving this service free of charge however ongoing increasing financial costs of running this service is making it increasingly difficult. Up until now we have resisted advertising as a means of a revenue stream to help run this forum but it has become inevitable that extra revenue is required to run this forum.

    We have introduced a donate button to help offset the cost of running this forum. It is completely voluntary, but if you would like to donate, all donations would be greatly appreciated.

    Thanks Murray..
    Dismiss Notice

Pump calculation question

Discussion in 'Equipment' started by JoshTaylor, Dec 31, 2011.

  1. JoshTaylor

    JoshTaylor New Member

    Joined:
    Dec 30, 2011
    Messages:
    10
    Hello all,
    I've attached a pdf of a system that we are thinking of building to provide food for those in need.
    I want to make sure that I get the right pump size for this system.

    Here are the calculations for the amount of water that we expect to have in the grow beds:
    Each GB
    4 ft x 3.33 ft x 1ft deep = 13.32 cubic feet x 7.5 gallons per cubit foot = 99.9 gallons per each GB
    If approx 33% is water, that equals 33.3 gal per GB x 12 GBs = Approx 400 gallons, assuming all have grow medium, but was planning on using 2 as raft systems, maybe, which would add approx 130 gallons for a total of 550 gallons of water in the GBs.

    My understanding from reading other threads is that I should plan on filling the grow beds approx 3-4 times per hour, which would mean that I would need approx 1500 gph.
    However, I also read that I should plan on twice that for a CHOP 2 system to feed the fish tanks. Is that true? If so, I believe I would need a minimum of 3000 gph pump. Probably leaning towards 4000 or 5000gph to allow for expansion.
    Thoughts?

    Also, I've seen quite a variance in watts used for the same gph. Any recommendations on brands of pumps for U.S. I obviously want to minimize watts used, but still be good quality. Thanks!!!
     

    Attached Files:

  2. MattySEQ

    MattySEQ New Member

    Joined:
    Apr 7, 2011
    Messages:
    495
    For a design this size imo I would use chop 1, chop 2 needs a larger pump capacity

    chop2 - your pumping to all the growbeds and fishtank then its gravity feeding from fishtank to sump

    chop 1 - you would be pumping to fishtank and gravity would do the work to the growbeds and then growbeds would drain into sump

    For your other question on floating raft on the other thread chop1 would also be more beneficial because the water in the sump is filtered so you could pump direclty to some floating raft and the fishtank, whereas in chop2 the sump has water flowing straight from the fishtank to the sump so the water you pump out of the sump would need the solids removed before a floating raft system could be used.

    As far as pump goes its to early for me to change gph to lph which I understand so I'll come back to it later when my heads not needing 4 panadol and 3 cups of coffee :)
     
  3. Murray

    Murray Site Admin Staff Member

    Joined:
    Jun 4, 2009
    Messages:
    7,638
    Country:
    Australia
    State:
    Queensland
    City:
    Brisbane
    Not true....sorry.
    The filtration process is ongoing and continuous. We have dozens of systems out there operating floating raft off a CHOP 2 system that work just fine.
     
  4. MattySEQ

    MattySEQ New Member

    Joined:
    Apr 7, 2011
    Messages:
    495
    I thought solids were a no no when it comes to raft systems?
     
  5. Murray

    Murray Site Admin Staff Member

    Joined:
    Jun 4, 2009
    Messages:
    7,638
    Country:
    Australia
    State:
    Queensland
    City:
    Brisbane
    They are, but what is not correct is the assumption that solids remain in the water column in quantities that prevent the raft section from working and working well.

    What you have assumed would appear to be logical on first thought, but the reality is that the system works very well. The filtration of the water is an ongoing continuous process. The water passes through the beds (the filters) over and over again as it does in any system.
    Suspended solids are not easy to remove and are often not visible to the naked eye. They will accumulate in the bottom of the grow beds, the corners of the sump and over time a thin film of solid material will be observed in the bottom of the raft tanks.

    The roots of the plants in the raft system are an excellent indicator of just how much suspended material is in the water column, and if it is getting out of hand.

    We have found that we need to clean the raft tanks (in rotation) about once very 18 months operating a system this way.
     
  6. JoshTaylor

    JoshTaylor New Member

    Joined:
    Dec 30, 2011
    Messages:
    10
    Thanks Murray, that helps a ton! So if I'm understanding correctly, I would not need to add any filtration between sump and rafts in that setup if I'm only planning on using 2 of the 12 GB's for raft?
     
  7. Murray

    Murray Site Admin Staff Member

    Joined:
    Jun 4, 2009
    Messages:
    7,638
    Country:
    Australia
    State:
    Queensland
    City:
    Brisbane
    You will find that it works just fine, but as pointed out earlier, I feel you need to check that you have enough sump volume.
     
  8. JoshTaylor

    JoshTaylor New Member

    Joined:
    Dec 30, 2011
    Messages:
    10
    Will do. Based on my calculations, if all the grow beds fill at the same time, it would only leave about 6" of water in the 3 sumps, which is cutting it close, so I'll look at adding more sump volume. Thanks for that recommendation.

    As for the pump calculation question, is it true that I should plan on the pump being able to fill the grow beds 3 times in an hour and then double that figure for the CHOP 2 for the fish tank?

    Happy New Year and thanks for all you do!!!
     
  9. Murray

    Murray Site Admin Staff Member

    Joined:
    Jun 4, 2009
    Messages:
    7,638
    Country:
    Australia
    State:
    Queensland
    City:
    Brisbane
    That would work out pretty right depending on how good the "head" is for the particular pump. If everything was perfect you would not need that much pumping power, but there are friction losses and so on to account for.
     

Share This Page