Hi again, folks!

I was wondering how much do you feed your algaetanks and how much KNO3 you dose??

In my tank - that is about 30 liters - I feed 1/3 tsp frozen food per day.

I may be wrong, but it just feels that it is not enough - I don't seem to get good growth if I don't dose KNO3 (besides feeding) at a rate of about 0,1 ml dry KNO3 per day, and even that seems to be a bit too little.

The light over my tank is a 70 w metal halide pendant with a 10K bulb.


Traces and Ca/KH/Mg are really abundant.

The amount of dry Nitrogen from frozen foods varies considerably.

I've always been somewhat bemused that folks insist that the bioload or the food is some stable source they can measure(not you!, in general).

NH4 and total N are hard to measure what actually gets to the plant/macro or micro algae. It's hard for me to measure it.

Food can be measured for NH4, NO3 etc by dry weight. It's a bit involved, and the food itself varies batch to batch as well.

Most of the weight is water in frozen foods.
So it's not that suprising you still need more KNO3.

Regards,
Tom Barr

Thank's for taking time to reply, Tom! Good to hear that You dont think I'm crazy when I see that more dosing could be needed, thanks!

BTW, I have high Ca (more then 500 ppm), high Mg (over 1500 ppm) and over 16 dH in my tank (hard water from the tap plus this stuff in the synthetic salt). Could the aforementioned "nutrients" - Ca, Mg and KH - supress the uptake of NO3? Or maybe promote it?

What do You think?

Not in marine plants really, Ca/Mg and KH are nutrients, the CO3/Ca/Mg are all needed, especially Ca and CO3.

Many macro's are mainly CaCO3 ......just like coral skeletons.......except macros assimilate and grow at least an order of magnitude faster than hard corals.

So they can pull a lot out of the water column.

Generally: Ca, CO3/KH, and NO3 and traces are the main players.

While some and myself included have added PO4, I think the systems can do quite well without dosing it as most systems are well adapted to P limitation.

Even here, I think adding say 0.1ppm PO4 from a KH2PO4 stock solution, or even 0.05ppm, 2x a week is ample along with feeding for most any tank.

IME, adding .4-.5ppm of PO4 causes some diatom blooms, but.......that was just 2 tanks, hardly a consensus and I just have not done enough dosing and measurements yet on marine macro tanks to say much.

But.........I would stick conservative abd slowly work your way up, but rather than focus on how much/diatoms etc, focus on the health of the plants.

That is the important thing/observation.

Regards,
Tom Barr

Okay, Tom, thanks again. I will try and raise my KNO3-dosings to about 1/10 of a teaspoon. The funny thing I've noticed is a lot more bubbles in my DSB then before I started with dosings.

The hard part is to remember to focus on the plants health and don't bother about pestalgae... takes some guts and patience sometimes.

Almost forgot:

for hard corals it is advised to keep NO3 down, because it supresses calcification.

I guess the NO3 doesn't do that for macroalgae (decreases the rate of calcification) because macroalgae don't take in so much Ca??

Why would it(NO3 at say 2-5ppm vs 10-20ppm) depress CaCO3 deposits?

I want a really good answer that's definitive before I buy that.
Why?

The macro algae have the same process..they too deposit CaCO3 into their structure.

That arguement(not directed towards you personally BTW!) about corals is nonsensical, basically a non answer.

By this arguement, we should also see issues with macro algae and more intense and faster with higher NO3 levels.
But we do not...........

I think they have other issues they have not resolved and have not dosed NO3 via KNO3 or an inorganic source.

Equating inorganic KNO3 to fish waste loading is a bad assumption, very bad.

The bubbles in the DBS: likely N2 gas, you just gave the bacteria a lot of NO3 which they like.

So some of the NO3 is being transformed rather than assimilated into plant/macro tissue.

Regards,
Tom Barr

Tom, it's such a relief to read Your posts!!

I experimented with doses of way over 60 ppm KNO3 and more then 5 ppm TMG in FW, with no ill effects, but with all the myths, missinformation and scary propaganda from reef folks I really became scared to dose more then just a speck of KNO3 and just a couple of drops of TMG in my saltwater tank.

And I mean I dont even have one single coral to worry about, but just thought that the nitrogen-argument about bad calcification could be applied to macroalgae as well. Thank You for clearing that out. Because I dont have Your experience and educational background I still fall into the trap that I tend to believe more what other people (reefers) say/imply then what my own eyes see.

Anyway - thanks a lot for busting some mythbubbles!!

Well, I am just trying to figure out why, at least in terms of CaCO3 deposition, a NO3 reading of 5ppm vs 20ppm is going to be an issue in marine tank for coral, but not Macro algae.

Simple question really.

Can the folks pushing the scare and doom reef rectify this question adequately in terms of physiology? Can they offer detailed dosing to show that this is the case with KNO3 dosing or.........not?

My guess is that most have never even heard of KNO3 dosing.
Let alone a difference between adding KNO3 vs an organic type of Nitrogen.

If they have, then they can talk about it.
If not, they truly speak based on ignorance.

Nothing wrong with being ignorant either, we all are about a great many things.

But a willingness to learn to no longer be ignorant about NO3 dosing is a good thing, simply not doing anythying test wise is, and I feel very strongly about this, a loser's arguement.

You learn nothing accepting such views.
You are expected to accept, not test and see for yourself.
Mere observation alone will only get you so far. At some point testing becomes a very effective method to learn more about things.

You need to test to see what really happens and what is really causing the probelms with the coral or with the macro algae. We all make assumptions, but some are good and some are downright bad.

Recall, many in the FW plant hobby assumed, and a few still do, that high PO4 = algae blooms.

But clearly when you are adding plenty of PO4 and have to algae, it really does not expainl things well as a model.

IME and IMO, most reef folks, like 99%, have little clue as to what specifically causes algae in their tanks.

They are not interested in inducing pest algae, but that is the only decent way to know why, at least one reason, that the pest algae appear in their tanks.

Most are unwilling, and I understand this, to trash their corals for an experiment

But with macros, they bounce back much faster, so they make a much better model to explore such issues.

Of course you need to know hwo to grow them to start with as well.

Regards,
Tom Barr

Hi all,
It's strange Patrik that you argue different things in different places and that the references you yourself gave when you started your nano all point to exactly what Tom is saying here. Did you not read the references you yourself cite? Based on those references you made alot of claims on this issue. Later you backed from the cleary incorrect ones. I have seen few "reefers" dispute your theoretically sound claims. Myself and several more even back you plausible ones.

I have seen no experimental data that high levels of NO3 limit the process of calcification, and I mean the chemical process itself.

In the case of Macros the study you cited about macroalgae indicates that non calcifying macroalgae may outcompete calcifying when N and P is dosed. That again has nothing to do with the depositing of CaCO3 itself, only the relative competitiveness of the different algae.

There is however significant experimental data that points to the fact that high levels of NO3 has negative effects on the coral as a whole. Theorized by some that nitrogen is used by the coral to manage its zooxanthellae. High levels of NO3 leading to zoox. overcrowding, coral browning, and also coral bleaching, coral ejecting it's zoox.. Stressed corals calcify less. Again, no direct connection between NO3 and calcification. Also there is the theory on CO2 limitation in the coral, reducing calcification, from higher zoox. activity as in your cited article Patrik.

You have disputed this, Patrik, in the past and I have understood that you changed your mind. Do you again argue that high levels of NO3 does not affect a coral? Tom, your position?

When I discuss with other "reefers" on reef forums I argue that a higher nitrogen flux is necessary. In starved systems, heavily skimmed, that means holding a measurable nitrogen level. In "high-bio" systems, like the nanos of Lasse Forsberg or Eric Bornemans skimmerless tanks, that flux comes from organic nitrogen. Mostly from bacterial biomass. This also implies dosing may be necessary in some cases.

You have also seen me argue in many places that NO3 may have to be dosed in starved reef systems using macroalgae as the primary export. This is to offset the relatively few N export paths in comparison with P export paths. I have backed your nano experiment since it's interesting at least from this perspective.

Noone of note is disputing your sound claims or trying to stop you from carrying out your interesting experiments. Several are arguing against your clearly incorrect claims. You have also, as I interpret your results, empirically proven some of your own claims to be false. Because we do not agree with you to 100% does not mean we disagree. In fact I'm still very much interested in your experiments.
//Mattias

P.S. These where the references given by Patrik during the onset of a long debate on a swedish forum about dosing in the presence of corals.

1. Coral growth in high-nutrient, low-pH seawater: a case study of corals cultured at the Waikiki Aquarium, Honolulu, Hawaii

SpringerLink - Journal Article

4. The Effect of External Nutrient Resources on the Population Dynamics of Zooxanthellae in a Reef Coral

http://links.jstor.org/sici?sici=008...2.0.CO%3 B2-X

2. Effects of Elevated Nitrogen and Phosphorus on Coral Reef Growth

http://links.jstor.org/sici?sici=002...3E2.0.CO%3B2-0

1. Nitrate increases zooxanthellae population density and reduces skeletogenesis in corals

SpringerLink - Journal Article

1. Nutrient-limited productivity of calcareous versus fleshy macroalgae in a eutrophic, carbonate-rich tropical marine environment

SpringerLink - Journal Article