pelagic
Well-Known Member
I started to tell people not to use GFO after I found out about what happened to my tank, especially when you have a larger tank. Here are the reasons:
Reason 1: Nitrate and Phosphate are both required for the creatures in the tank
Redfield ratio - Wikipedia, the free encyclopedia
Redfield ratio or Redfield stoichiometry is the atomic ratio of carbon, nitrogen and phosphorus found in phytoplankton and throughout the deep oceans. This empirically developed stoichiometric ratio is found to be C:N
= 106:16:1. The Nitrate(NO3) to Phosphate(PO4) Ratio to keep is about 20:1 to 30:1. You don't have to chase the numbers if your corals are doing fine and healthy.
Reason 2: Higher Phosphate and Nitrate will not necessary kill your corals, but NP imbalance will
http://youtu.be/ZRIKW-9d2xI
Reason 3: If you have bio-pellets/Cheto/ATS, it won’t work well with GFO
Eventually, P will always be un-detectable, because it’s used/absorbed as soon as it’s produced. Your nitrate will raise slowly until your corals start dying, it will trigger the chain reaction and crash your tank.
TO Use GFO When:
DO NOT USE GFO when:
If your NP Ratio is far off
Let say more than 100:1, at one point, my phosphate was constantly at 0 (hanna 736) and nitrate was over 100. You can
I hope it helps with people planning on adding/currently using GFO now. It's surely a double edged sword.
Reason 1: Nitrate and Phosphate are both required for the creatures in the tank
Redfield ratio - Wikipedia, the free encyclopedia
Redfield ratio or Redfield stoichiometry is the atomic ratio of carbon, nitrogen and phosphorus found in phytoplankton and throughout the deep oceans. This empirically developed stoichiometric ratio is found to be C:N
= 106:16:1. The Nitrate(NO3) to Phosphate(PO4) Ratio to keep is about 20:1 to 30:1. You don't have to chase the numbers if your corals are doing fine and healthy.Reason 2: Higher Phosphate and Nitrate will not necessary kill your corals, but NP imbalance will
http://youtu.be/ZRIKW-9d2xI
Reason 3: If you have bio-pellets/Cheto/ATS, it won’t work well with GFO
Eventually, P will always be un-detectable, because it’s used/absorbed as soon as it’s produced. Your nitrate will raise slowly until your corals start dying, it will trigger the chain reaction and crash your tank.
TO Use GFO When:
- You have a small tank, and you can change more than 25% of the water at a time. This way, when you have nitrate issue, you can export the nitrate fairly easily
- You have Zeolite to absorb Nitrogen, before it turns into Nitrate. You should not have the issue to control both N and P at a low level with the zeolite, and GFO
- When you Nitrate to Phosphate ratio is less than 10, and your phosphate is relatively high (let say 0.5 PPM)
DO NOT USE GFO when:
- You have Bio-Pellets, it’s a big no no! To adjust nitrate/phosphate ratio, simply feed animal based food when the nitrate is too high, vice versa. It’s because animal based food contains more phosphate.
- You can’t change more than 25% of the water, NP Balance Issue.
- When you have large amount of live rock, sand and hard to clean area in your tank. Nitrate can be stored in a solid form (dust) and stay in your sand and rock and release it slowly. If you don’t have phosphate, and you can’t keep up with water change for a period of time, your nitrate level will rise quicker than phosphate.
If your NP Ratio is far off
Let say more than 100:1, at one point, my phosphate was constantly at 0 (hanna 736) and nitrate was over 100. You can
- Feed More Animal based food
- Water Change
- Zeolite
- Nitrate Reactor
- Deep Sand bed
- Dose Phosphate
(eg: Seachem. Flourish Phosphorus) - Make sure you are not adding more than 0.03 PPM PO4 to your tank a day. Monitor your PO4 and PH Level daily at least for the first few days.
- PS: Hanna 713 Tests Phosphate in PPM, 736 tests Phosphorous in PPB
Example: Hanna 736 reads 12 PPB, then it’s 12 x 3.066 / 1000 = .0367 ppm PO4
I hope it helps with people planning on adding/currently using GFO now. It's surely a double edged sword.
Last edited:
