Hi Matt,
I read only partially the topic. It struck me. I re-lived much of my past.
I spent my aquarium life playing with carbon sources, nitrogen and phosphorous.
I nearly lost my previous 150 gal tank and I've started a 350gal 1 year ago. SPS only, as always.
--Briefly, what was the cause of almost losing your first tank? ( Optional.
)
I decided to write here some of my experience because it could be helpful to You and to all other readers.
I think it is too hard to explain the whole path that lead to my actual thoughts, it surely would be too long and incomplete.
So I will write my thoughts only, and let You decide if asking for details.
In the water there is a need to balance bacteria and algae. Without algae (read also microalgae, algae film, not green hairy or macros), bacteria are free to grow up uncontrolled and destroy everything.
--I'm not sure I understand why this is... I assume that this is the case because without algea, the bacteria has no competitors for nutrients and can grow unchecked?
Algae (and corals) need inorganics. Inorganics are ammonia, nitrate and phosphate.
--don't bacteria need these things as well? As well as iron, I guess
If inorganic N or P is zero, bacteria get advantage and grow up too fast. In this case bacterial film appears on glass panes (that whitish powder-like that forms in few hours, and is so tiny that a fish passing in proximity leave lines on it) and in the worst of case happens a bacterial bloom, in particular if adding carbon sources, even in minimal doses.
--I don't understand this process.. How do bacteria get the advantage when n or p are zero.. Like you mention below, isn't this when the tank becomes 'limited' and we get either n or p rising out of control?
The balance between the fish population and light determines the amount of inorganics. The larger the fish population and the lower the power and duration of light, the higher will be the inorganics, and vice versa of course.
-- interesting but I don't really understand this.. Yes there is much discussion about nutrient starved corals getting stressed by intense light (mostly when dealing with LEDs) but I don't think you are really taking about this..
-- I really don't see the causal relationship between large fish population, low light and high organics- are you saying that the corals will absorb more nutrients when light is more intense and longer photoperiod? What about all the other non photosynthetic organisms consuming n and p?
---- I really don't think I understand that statement... Unless you are referring to nutrient uptake by the corals..
Organic carbon sources do not act on inorganics. Heterotrophic bacteria act on organic compounds. The skimmer too acts only on organics compunds. They both do anything on inorganics.
-- ok I really need a clinical explanation of the difference between organic and inorganic. Above you say that inorganic compounds are nitrate, phosphate and ammonia.. I thought that this is exactly what bacteria feed on and I also thought that a skimmer, by removing solid waste from the aquarium does indeed play a part in reducing n and p and ammonia by removing solids that would otherwise be broken down into said nutrients...
Organics mostly (not in absolute and only) determines zoox concetration in corals.
Inorganics determines growth and health of SPS.
--- I also do not understand this distinction.... I guess because I don't really understand the difference between 'organic' and 'inorganic'... Sorry.. Again I need some explanation...... I never got very far in biology class in high school..
I wish I had... It would make reef keeping easier!!
When N is zero and P is high, there is N deficiency. Add N or remove any P remover.
When N is high and P is zero, there is P deficiency. Add P or remove N remover (do not even know if they really works in seawater).
--yes!!
this I get!
SPS love near-zero organics and enough inorganics. If we add food (any kind of food), we add organics. If we add fishes (but not their food), we add inorganics; so if You want to increase inorganics, add fishes, and give them the food they need to live, not any more.
--ok, so fish poo is inorganic- solid stuff??
Increasing organics hurts SPS.
-yes, this seems to be conventional wisdom... Don't tell Richard Ross.. he'll make you guess his phosphate level!
-- my no3 is 6ppm (due to kno3 additions) and my po4 is .16 and my corals have NEVER looked better. Growth is increasing weekly as well.. I have about 25 fish in the tank and I feed them and I add coral foods as well.....
Some months ago I had 0,2ppm NO3 and 0,02ppm PO4. I added a second skimmer, I added and doubled GAC. I started using NBP in a small dose and progressively increased the volume to 1,5 liter. I started adding daily 4 drops of pure acetic acid and increased to 8 drops/d. I still have 2 skimmer, 2 liters GAC, 1,5l NBP and add 8 drops/d acetic acid.
-- to me, I read above that you had extremely low nutrients and you attempted to aggressively lower them even more... Is this correct? Do you consider .2 ppm n and .02 ppm po4 to be high?
My fish population remained the same and I kept the same amount of food I was giving. I continued changing the same amount of water every week, with the same salt.
I do not add anything else to my tank.
Ny nitrate remains 0,2ppm and PO4 0,02ppm.
My corals have improved greatly, but growth is scarce.
-- so, you increased nutrient export dramatically but nutrients did not drop at all?
In the last two weeks, I started adding inorganics boluses. I add a dose of NaNO3 and a dose of NaH2PO4 (about +1,5ppm NO3 and +0,05ppm PO4). In a couple of days, NO3 get back to 0,2 and PO4 to 0,02ppm and I add another bolus. PE is increasing, tissues appears brighter, more brilliant and thick and new branches are appearing.
It seems to me boluses every few days is better than keeping constant higher levels (I tried that too previously).
-- so ultimately, in very basic unscientific terms, it seems to me that you are saying strip the water column of all nutrients and then blast the corals with large (controlled) doses of nitrates and phosphates on a periodic and irregular basis..
I hope it can be useful. Do any question, if You feel.
Luca
