Why to add nitrates to maintain Redfield ratio

Discussion in 'Reef Chemistry' started by zeroinverse, Jan 9, 2016.

  1. zeroinverse

    zeroinverse Guest

    Jul 17, 2011
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    In case you guys have not come across this article... It is a great read for SPS growers.


    General summary:

    -Keep Nitrates above Phosphates

    -GFO strips out more than just phosphates (minerals, etc) and requires a follow up water change to replenish lost minerals. (So don't use GFO)

    -add potassium nitrate, sodium nitrate, or calcium nitrate to dose nitrate.

    -SPS needs nitrates and phosphate to grow.

    -browned out SPS means too much nutrients, not enough light.

    -light/pale SPS means not enough nutrients, too much light.

    -macro algae love nitrates, so do the symbiotic plankton in SPS.

    -first dose of nitrates will need to big larger amount since your tank will soak it up.

    -minimize pellets (except to use it to add phosphates)

    -bio-pellet and carbon dosing remove nitrates faster than phosphates, so it leaves you with low nitrate, higher phosphate ratio over time. This is bad for SPS growth. (So stop use of fast nitrate removers - i.e. Stop carbon dosing and bio-pellets).
  2. Enderturtle

    Enderturtle Volunteer

    Apr 10, 2014
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    @jonmos75 aren't you dosing nitrates and phosphates to maintain this ratio? Ever notice any pest algae problems, it's suppose to prevent pest algaes from growing right?
  3. jonmos75

    jonmos75 Supporting Member

    Nov 12, 2014
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    Yes I am a firm believer in the redfield ratio...
    Yes I have nitrogen & phosphorus (Seachem) that I will does at times when my levels get to low....

    So right now I am in a transition period trying to fine the correct balance for my tank....

    I use bio-pellets and I agree with Zero that it drops nitrates faster then phosphate so I started dosing a 50/50 mix of RODI water and Brightwells Phoshat-E to run trough a dosing pump to lower the phosphates and this kept my po4 at .02-.06 with in a range that I could handle, yet what I (Think) has happened is when dosing Phosphat-E it had stalled out my bio-pellet reactor as my nitrates would not be lower then 4.0...(in the article this says this is good.....well not in my case)

    Things I noticed:
    ~Would have to clean the glass almost daily (green algae)
    ~po4 (0.02) & no3 (4.0) this is no where close to the redfield ratio!!!! 306:1 not the recommended 16:1
    ~Montis were starting fade out and loose tissue RTN on a couple of acros.... Anemones receding...ect

    Solution that I am trying to get back into the redfied ratio of 16:1 no3(.21) and po4(.02):
    ~I turned off the Phosphat-E dosing
    ~I went back to dosing nopox (4ml) a day in the morning to lower the no3 & po4 (ONLY until po4 & no3 are in the correct range) (will stop this weekend)
    ~Dosed 15mL of Microbactor7 a day to re-seed the bio-pellet reactor to see it it can maintain again...(will back it down to 5mL weekly once reactor is working again)

    Note:Using the bio-pellet reactor and if PO4 does rise again might use Phosphat-E to spot dose to lower po4 back into 0.02 but will have to test this concept to see if it will work...

    Another thing I have noticed:

    My Alk was slowly climbing 7.5 to 8.9 (I use a peristaltic pump so my effluent drip rate is extremely consistent...and did not change my Calcium was staying stable at 420 and Mag was stable at 1280) I saw my CO2 cylinder was low on the gauge so I swapped it out...
    Yet what I noticed is that when my alk was up in the 8.5-9.0 my Acans started to get puffy that weren't doing so well running the alk in 7.5 range...

    So what I take from all this is what works great in one system may not work in an other system, but the key is learning how to watch your tank and understand why something is reacting the way it is and how to react properly to correct the issues you are seeing and not reacting to quick (patience) and not perform too many different adjustment at the same time as you wont know exactly which action really worked...

    The other difficult task as I will say a majority of us do not have corals from one region of the world so each of the different corals that we have in out tank all need different requirements of Alk, Mag, Ca, so to find a good balance to keep all the SPS, LPS ect happy is not an easy task, but make this hobby fun.
    Enderturtle likes this.

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