Active maintanance of nutrient levels vs "passive" approach

92Miata

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I don't know what to do now. Should I actively dose to keep NO3 around 5-10 ppm and PO4 around 0.1 ppm or just let the tank do its thing? I read many people keeping their nutrients this low, but with sps dominated tanks. Mine is still a work in progress with a mix of mushrooms, softcorals, lps and sps, so I fear that NO3 lower than 5ppm might be risky.
Here's the thing - inorganic nitrate and phosphate readings are just a tiny piece of the picture with regards to nutrients (and nitrogen and phosphorus).

There's a camp that says keep them as low as possible, and there's a camp that says you need to keep them above X and Y, and they're both essentially correct, and wrong. The issue is they put way too much meaning on the test results.

Corals need nitrogen and phosphorus - but typically only small amounts. For phosphorus, corals are really efficient at pulling inorganic phosphate out of the water - so constantly measurable phosphates are an easy way to make sure they're getting enough. You'll generally find that the people who feel that keeping phosphate above zero is an absolute necessity tend to feed less.

What you'll find in the people who keep 0.00 is that they tend to have been in the hobby a long time, keep a lot of fish, and feed a ton (what the other group finds to be an obscene amount of food), and have older rock that has all sorts of microcritters eating and pooping and breeding and cycling phosphate. Each time they put food in the water, they're putting phosphate in the water, and corals grab what they can. If you feed enough, you can get corals all the phosphate they need, and if you skim/etc enough, you can keep those numbers zero. Feed heavy/skim heavy is probably as close as you can get to natural conditions, but it's really hard to get right in tanks with immature rock.

The 2nd method is probably better, but the first is much safer, because coral death by phosphate deprivation is fast.


Nitrate is a little different - corals don't like nitrate - they can use it for nitrogen, but its biologically expensive - they basically have to upconvert it to ammonia. They much prefer ammonia. The best way to make sure your corals get enough ammonia is to have lots of fish, or feed a lot. Fish are basically slow release ammonia dispensers. Now, like I said - corals prefer ammonia, but they can use nitrate. Which means having some in the water column makes things a little safer, because again, deprivation kills corals quickly.


There is absolutely nothing wrong with dosing nutrients. There is nothing natural or balanced about immature reef tanks - you need to intervene when things get out of whack.
 
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Here's the thing - inorganic nitrate and phosphate readings are just a tiny piece of the picture with regards to nutrients (and nitrogen and phosphorus).

There's a camp that says keep them as low as possible, and there's a camp that says you need to keep them above X and Y, and they're both essentially correct, and wrong. The issue is they put way too much meaning on the test results.

Corals need nitrogen and phosphorus - but typically only small amounts. For phosphorus, corals are really efficient at pulling inorganic phosphate out of the water - so constantly measurable phosphates are an easy way to make sure they're getting enough. You'll generally find that the people who feel that keeping phosphate above zero is an absolute necessity tend to feed less.

What you'll find in the people who keep 0.00 is that they tend to have been in the hobby a long time, keep a lot of fish, and feed a ton (what the other group finds to be an obscene amount of food), and have older rock that has all sorts of microcritters eating and pooping and breeding and cycling phosphate. Each time they put food in the water, they're putting phosphate in the water, and corals grab what they can. If you feed enough, you can get corals all the phosphate they need, and if you skim/etc enough, you can keep those numbers zero. Feed heavy/skim heavy is probably as close as you can get to natural conditions, but it's really hard to get right in tanks with immature rock.

The 2nd method is probably better, but the first is much safer, because coral death by phosphate deprivation is fast.


Nitrate is a little different - corals don't like nitrate - they can use it for nitrogen, but its biologically expensive - they basically have to upconvert it to ammonia. They much prefer ammonia. The best way to make sure your corals get enough ammonia is to have lots of fish, or feed a lot. Fish are basically slow release ammonia dispensers. Now, like I said - corals prefer ammonia, but they can use nitrate. Which means having some in the water column makes things a little safer, because again, deprivation kills corals quickly.


There is absolutely nothing wrong with dosing nutrients. There is nothing natural or balanced about immature reef tanks - you need to intervene when things get out of whack.
Wow. Thanks for the detailed info. It has been few weeks since my message: What I have been doing lately is to feed more often powder food and feed more frozen while I dose to keep no3 around 5ppm. This is just for safety because I have only 2 tiny fish in the tank. On top of that I am dosing AF energy, which should feed corals on top of powder food. I am not testing PO4 anymore because I have been dosing heavily silicates (it interferes with the test), and the tank seems healthy so I decided to ignore the parameter for a while. The skimmer is running very dry now so I do not export too much organics too fast.
 

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