I'm dying on this hill - Phosphate is more important than alkalinity

Potatohead · Feb 24, 2020

I would love to add more fish. All I have is a yellow tang, two percs and a melanurus. I did also have a diamond goby but he up and vanished a couple months ago, I think consuming dinos for months may have done him in, but not sure.

I'm hesitant to add fish because I don't have any more copper and it's banned up here now. I could get some out of the States if I really wanted to. Between disease and possible aggression I am just hesitant to upset the apple cart. I would love a black cap basslet and a flame hawk though.

Hans-Werner · Feb 26, 2020

Scrubber_steve said:
"With nitrate at .6 and phosphate at .29, you're at a very excellent N/P range."
According to Hans Werner phosphate at .29 is "really bad"!

That is not exactly what I meant. Some people are very happy with even higher phosphate concentrations although with more than .15 ppm it starts to get quite high. It is rather the extremely low concentrations that are really bad.

vessxpress1 said:
I though 0 phosphates was the target.

Me too in the '90s, but slowly I started to understand what it really means that under coral reef concentrations coral growth usually is phosphate limited.

Here and here two scientific articles about phosphate concentrations in coral skeletons.

N : P ratios of 5 : 1 to 10 : 1 come close to my results with fertilization trials. The optimum concentrations in tank water may be different because minimum concentrations where corals are still able to take up nutrients are quite close together for phosphate, ammonia and nitrate. Some corals need at least around 0.02 ppm phosphate and 0.04 ppm nitrate or maybe 0.01 ppm or less total ammonia for a net uptake of these nutrients, but this may differ a bit between species. This means very low concentrations of N-compounds are sufficient to fulfill corals needs but phosphate should be present at detectable concentrations to make sure it is enough.

In my experience the symptoms of N and P starvation are different.

N deficiency makes the corals get quite pale but otherwise they stay healthy and soon regain color when they get more N compounds.

With phosphate starvation corals quite early show tissue necrosis with or without further symptoms. This seems to depend a bit whether N is available as ammonia or nitrate. Bleaching and tissue necrosis from the tips and exposed parts only occurs when corals have to use nitrate as N source. With ammonia as N nutrient the corals otherwise usually look quite good in color and may even open up quite good but show tissue necrosis from the base.

jk1151 · Feb 26, 2020

Really great read! Thanks for starting this thread. I’m just getting started with my tank and this seems very helpful!

Neoalchemist · Feb 27, 2020

Potatohead said:
I would love to add more fish. All I have is a yellow tang, two percs and a melanurus. I did also have a diamond goby but he up and vanished a couple months ago, I think consuming dinos for months may have done him in, but not sure.

I'm hesitant to add fish because I don't have any more copper and it's banned up here now. I could get some out of the States if I really wanted to. Between disease and possible aggression I am just hesitant to upset the apple cart. I would love a black cap basslet and a flame hawk though.

Ive been kicking around the idea for a long time that more fish faster may just be the cure for early tank dinoflaggellates.
Its one of a few things that are differant from "back in the day" when dinos were the exception not the rule.
Back then the sequence was live rock and sand, then cycle and clean up crew, then ramp up to full tank of fish, then corals. Nowadays everyone is afraid of overloading the system with fish early or at all
So tanks are dealing with low nutrient problems rather than the high nutrient problems we dealt with for a decade or so.

Potatohead · Mar 8, 2020

So thought I would bump this with an update...

Tank still looks great. This beside the fact at some point in the last week or so my fuge light stopped working and when I checked my phosphate today it was 0.26 ;Bored. Mind you I did check at the beginning of my photoperiod when I usually check towards the end, but it's still elevated. So I went out and got a new fuge bulb and slowed my dosing for now but I'm not going to go nuts on reducing it because most everything is much improved over 6 weeks ago. Ideally I would like 0.08 - 0.14 range.

Here's another pic of the coral I posted in this thread a few weeks ago, lots of new branches sprouting.

ScottB · Apr 30, 2020

Magellan said:
I feed 4-5x a day between corals/fish and leave a bag of phosguard in 24/7. Po4 stays around .03 and my mixed reef is happy, growing, and clean. But I bet you’re right, I’m sure I would have issues if I didn’t feed all the time and left the phosguard in.

I have seen this over and over as a pattern. The folks who can safely run lower nutrients are the ones feeding the corals with fish poop several times a day. Zeovit (bacteria) folks run like this. Lots of poop in, lots of export, low nutrient.

Potatohead · Apr 30, 2020

Since this has been bumped I thought it might be interesting to post another pic of the coral above. This was actually taken a couple weeks ago now, so about five weeks or so from the last pic to this pic

drawman · Apr 30, 2020

Potatohead said:
Since this has been bumped I thought it might be interesting to post another pic of the coral above. This was actually taken a couple weeks ago now, so about five weeks or so from the last pic to this pic

Have you noticed most/all other acros acting accordingly?

Potatohead · Apr 30, 2020

drawman said:
Have you noticed most/all other acros acting accordingly?

90% of them have had a huge change. This coral is one example but this is happening with just about every coral in the tank - Euphyllia too. I am not kidding when I say I have had more growth in the last three months than the previous 18. Polyp extension and color are much better as well. AND the tank is much cleaner visually.

I should take some pics of the other ones and then again in about a month. I wish I did that before.

I am trying not to be too enthusiastic or whatever about this but I cannot overstate how much of a difference this made for my tank and for my outlook of my future in the hobby in general.

ScottB · Apr 30, 2020

Since my frag system dino episodes (yes, plural) I have been keeping PO4 between .12 and .18.

For a while after it was kinda "ugh" with some algae, cyano, etc. It began to settle down a little as I wound down the dosing, and ramped up my feeding.

Gradually over 3 or so months of no dosing, but buckets of frozen & nori dumped 4 times a day, the tanks are cleaner than ever. The other thing that must have helped was moving ~ 50lbs of old live rock from my display into the frag sumps.

drawman · Apr 30, 2020

ScottB said:
Since my frag system dino episodes (yes, plural) I have been keeping PO4 between .12 and .18.

For a while after it was kinda "ugh" with some algae, cyano, etc. It began to settle down a little as I wound down the dosing, and ramped up my feeding.

Gradually over 3 or so months of no dosing, but buckets of frozen & nori dumped 4 times a day, the tanks are cleaner than ever. The other thing that must have helped was moving ~ 50lbs of old live rock from my display into the frag sumps.

I've been wanting a larger sump for exactly that reason.

Ross Petersen · Apr 30, 2020

If keeping nitrates around 5-10 ppm and phosphates around 0.05 to even 0.1 ppm is indicative of success in a lot of established reef tanks... what's the value in all these phosphate reactors and mega nutrient export systems, both chemical and physical in nature? Is the pendulum swinging a bit here?

I'm inclined to believe there's merit in simply having a good skimmer at the appropriate size, changing socks/floss regularly, feeding in moderation, seeding as much biodiversity as one can, and keeping nutrients at stable but NOT super-low levels (e.g., by dosing PO4 and NO3 sometimes).

Is this line of thinking naive?

Pdash · Apr 30, 2020

Ross Petersen said:
If keeping nitrates around 5-10 ppm and phosphates around 0.05 to even 0.1 ppm is indicative of success in a lot of established reef tanks... what's the value in all these phosphate reactors and mega nutrient export systems, both chemical and physical in nature? Is the pendulum swinging a bit here?

I'm inclined to believe there's merit in simply having a good skimmer at the appropriate size, changing socks/floss regularly, feeding in moderation, seeding as much biodiversity as one can, and keeping nutrients at stable but NOT super-low levels (e.g., by dosing PO4 and NO3 sometimes).

Is this line of thinking naive?

Seems about right, but I guess it depends on how many fish you would like. If you want multiple large tangs, huge schools of anthias and chormis, etc. then I guess you will need the extra equipment, if not then I would expect not.

Potatohead · Apr 30, 2020

Pdash said:
Seems about right, but I guess it depends on how many fish you would like. If you want multiple large tangs, huge schools of anthias and chormis, etc. then I guess you will need the extra equipment, if not then I would expect not.

I think this is sound theory. Plus, each tank is different. Some will require a fuge and gfo and a huge skimmer to keep nutrients low while others simply will not. I thought I needed all that extra stuff too and now half of it sits on my storage shelf. I do run a fuge but only a low powered light for eight hours, and a skimmer, because they provide other benefits beyond just nutrient removal. My gfo reactor was kicked to the curb eons ago.

ScottB · May 1, 2020

drawman said:
I've been wanting a larger sump for exactly that reason.

I have three sumps on my frag system each holding rock. Adding the rock was not an overnight fix, but I am a believer now after about 3 months.

ScottB · May 1, 2020

Ross Petersen said:
If keeping nitrates around 5-10 ppm and phosphates around 0.05 to even 0.1 ppm is indicative of success in a lot of established reef tanks... what's the value in all these phosphate reactors and mega nutrient export systems, both chemical and physical in nature? Is the pendulum swinging a bit here?

I'm inclined to believe there's merit in simply having a good skimmer at the appropriate size, changing socks/floss regularly, feeding in moderation, seeding as much biodiversity as one can, and keeping nutrients at stable but NOT super-low levels (e.g., by dosing PO4 and NO3 sometimes).

Is this line of thinking naive?

That is largely in line with my thinking, although I am finding everyone is happier with more feeding and commensurate removal. Skim, socks, two week WC.

I still keep a GFO reactor in my DT sump but right now it isn't running. I test PO4 once a week and if it moves any higher than .16 or so, I will set it to run for a few hours a day until my next test. I load the reactor with a very SMALL amount of GFO so there is no risk of stripping.

sde1500 · May 1, 2020

Ross Petersen said:
If keeping nitrates around 5-10 ppm and phosphates around 0.05 to even 0.1 ppm is indicative of success in a lot of established reef tanks... what's the value in all these phosphate reactors and mega nutrient export systems, both chemical and physical in nature? Is the pendulum swinging a bit here?

I'm inclined to believe there's merit in simply having a good skimmer at the appropriate size, changing socks/floss regularly, feeding in moderation, seeding as much biodiversity as one can, and keeping nutrients at stable but NOT super-low levels (e.g., by dosing PO4 and NO3 sometimes).

Is this line of thinking naive?

Not naive, no. But if your nutrient input is massive, your export needs to be so as well. Sometimes those tools are needed, as they allow you to feed very heavily, while mitigating the risk of runaway nutrients and algae.

Ross Petersen · May 1, 2020

sde1500 said:
Not naive, no. But if your nutrient input is massive, your export needs to be so as well. Sometimes those tools are needed, as they allow you to feed very heavily, while mitigating the risk of runaway nutrients and algae.

Sounds like balance is key as with most things. Thanks for the valuable insights. Going to consider transient GFO down the road but only if things get out of balance.