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

[living_tribunal]

Really interesting thread!

Some food for thought:

- Hobby tests kits measure orthophosphate, and not other forms, so how much total phosphorus is actually present in a given aquarium is not often known. Probably a minor difference, but worth considering since bacterial action can convert organic phosphate back into inorganic form.

- The same goes for NO3: other forms of nitrogen available to corals and their symbionts like organic N (amino acids) and inorganic N as ammonium are usually not being factored in when talking about "N-P ratios".

- As @living_tribunal mentioned, elevated PO4 can result in increased tissue growth rates at the expense of the integrity of the animal's calcium carbonate skeleton and lead to more fragile corals. Increased growth and coloration aren't in themselves a proxy for determining overall coral health. Upping PO4 to encourage growth should probably be done carefully in tanks with lower alkalinity. Running at elevated alkalinity can help the skeletal growth keep up with the increased tissue growth.

- I'm not aware of any research looking at phosphate specifically, but there are some papers showing that elevated NO3 can either increase OR decrease growth rate in corals depending on the species. It would be really cool to see that Rosset et al. paper expanded on to corals other than Euphyllia paradivisa to see if species makes a difference in those ratios.

A study evaluating acro growth at various phosphate levels, everything else held constant.

New study documents increased growth of staghorn Acropora in higher phosphate levels | Reef Builders | The Reef and Saltwater Aquarium Blog

Acropora corals are a mysterious creature with complex needs and one of those that we thought we’d nailed long ago was their “need” for minimal phosphate concentration in the water. A new study by…

reefbuilders.com

 

[lelandmarine]

A study evaluating acro growth at various phosphate levels, everything else held constant.

New study documents increased growth of staghorn Acropora in higher phosphate levels | Reef Builders | The Reef and Saltwater Aquarium Blog

Acropora corals are a mysterious creature with complex needs and one of those that we thought we’d nailed long ago was their “need” for minimal phosphate concentration in the water. A new study by…

reefbuilders.com

good find from the past

 

[bcarl77]

I am well onboard with this trend of keeping phosphate levels closer to 0.1PPM. Unfortunately, I am having a hard time getting there. Was stuck at near 0 for several months, finally getting it to 0.04-0.05ppm...

 

[living_tribunal]

I am well onboard with this trend of keeping phosphate levels closer to 0.1PPM. Unfortunately, I am having a hard time getting there. Was stuck at near 0 for several months, finally getting it to 0.04-0.05ppm...

I think this might be the wrong approach. We shouldn’t set a standard of x ppm phosphate levels, as it’s not always the answer and healthy natural reefs have phosphate levels between .01-.035 (with much higher availability than our tanks of course). Instead, I propose a shift in thinking among the reefing community.

For decades, the prevailing thought was lps like high nitrate and phosphate is the greater limiting factor to nuisance algae. We should now divert newcomers attention to lowering their nitrate levels instead (assuming phosphate isn’t out of control).

I see it everywhere on r2r, “I keep higher n because my corals love dirtier water”, or “I had an algae break out so I started GFO”. People have been convinced that nitrate plays a lesser role in this than do phosphates. They also don’t see the connection when their corals begin to bleach and polyp extension shrinks. 9/10 times when I see bleaching or pe posts, they post everything but their phosphate levels. When I ask for the phosphate levels, the answer is always “0”. And as soon as they raise po4, their tank is happy again.

So let’s communicate the importance of phosphate availability and the negative impact of high N instead (once again, for those that love to argue semantics, high N in itself is not bad, the algae it causes is).

 

[living_tribunal]

I am well onboard with this trend of keeping phosphate levels closer to 0.1PPM. Unfortunately, I am having a hard time getting there. Was stuck at near 0 for several months, finally getting it to 0.04-0.05ppm...

(But yes, .1-.15 phosphate with 0.5N has been the sweet spot for me )

 

[Fragzilla]

I’ve been trying to tell people this for years, I seldom post online now as people would argue blindly with me. My 8 year old reef tank only has a skimmer on a very dry setting. My phosphate is 1.5ppm and no3 goes from 20-80ppm depending on how much water changes I make. It’s all about balance, you will eventually want higher alk levels with your higher nutrient levels as the nutrients are acidic compounds. That said there is only a small difference with that sort of tank. If your ULNS everything has to be exact and any spikes are unforgiving. If you want to keep your Corals for a long time don’t starve let them have all the nutrients they want and you’ll also have a less stressful experience in the hobby.

 

[Potatohead]

I think this might be the wrong approach. We shouldn’t set a standard of x ppm phosphate levels, as it’s not always the answer and healthy natural reefs have phosphate levels between .01-.035 (with much higher availability than our tanks of course). Instead, I propose a shift in thinking among the reefing community.

For decades, the prevailing thought was lps like high nitrate and phosphate is the greater limiting factor to nuisance algae. We should now divert newcomers attention to lowering their nitrate levels instead (assuming phosphate isn’t out of control).

I see it everywhere on r2r, “I keep higher n because my corals love dirtier water”, or “I had an algae break out so I started GFO”. People have been convinced that nitrate plays a lesser role in this than do phosphates. They also don’t see the connection when their corals begin to bleach and polyp extension shrinks. 9/10 times when I see bleaching or pe posts, they post everything but their phosphate levels. When I ask for the phosphate levels, the answer is always “0”. And as soon as they raise po4, their tank is happy again.

So let’s communicate the importance of phosphate availability and the negative impact of high N instead (once again, for those that love to argue semantics, high N in itself is not bad, the algae it causes is).

It's a fine line it seems. In the last year since I started dosing phosphate the P level has been pretty constant, with a few swings while things were stabilizing, but mostly in the .1 - .14 range. When I started dosing P, my nitrate was always around 8. A few months after dosing P, it fell to near zero. I did see a negative reaction in some corals and the colors were certainly more pale. The affected corals recovered over the next few weeks and growth and polyp extension were always fine. I started feeding the tank about twice as much to get the nitrate to about 2 or so.

Fast forward to ~eight weeks ago, I removed my filter roller for a couple reasons. My nitrate went from 2-3 to about 8-10 again in the next 3-4 weeks. Colors definitely became more dense, I don't notice much difference in polyp extension, but again there is some negative reaction with some corals and there are a very small amount of dinos here and there if you look closely. I am expecting the tank to stabilize over the next few weeks and things will be fine again.

I guess I mostly agree with nitrate being much less important. But, it does seem to have a significant effect on acro colors, or at least the density of the existing colors.

 

[drawman]

It's a fine line it seems. In the last year since I started dosing phosphate the P level has been pretty constant, with a few swings while things were stabilizing, but mostly in the .1 - .14 range. When I started dosing P, my nitrate was always around 8. A few months after dosing P, it fell to near zero. I did see a negative reaction in some corals and the colors were certainly more pale. The affected corals recovered over the next few weeks and growth and polyp extension were always fine. I started feeding the tank about twice as much to get the nitrate to about 2 or so.

Fast forward to ~eight weeks ago, I removed my filter roller for a couple reasons. My nitrate went from 2-3 to about 8-10 again in the next 3-4 weeks. Colors definitely became more dense, I don't notice much difference in polyp extension, but again there is some negative reaction with some corals and there are a very small amount of dinos here and there if you look closely. I am expecting the tank to stabilize over the next few weeks and things will be fine again.

I guess I mostly agree with nitrate being much less important. But, it does seem to have a significant effect on acro colors, or at least the density of the existing colors.

This has always been the trouble for me running tanks with a low fishload and barebottom. I can only feed so much and dosing has to be balanced.

I do like the thoughts in this thread. One day I'll have a tank with a heavier fish load.

 

[Potatohead]

This has always been the trouble for me running tanks with a low fishload and barebottom. I can only feed so much and dosing has to be balanced.

I do like the thoughts in this thread. One day I'll have a tank with a heavier fish load.

My tank has sand, I do believe it helps. I just made a couple fairly large changes to the system (started dosing phos, then it stabilized, then after six months of that I removed the roller filter) so it takes some time to re-balance again. I am hoping now it will stabilize in the nutrient range I am looking for.

 

[Samoks]

What are you dosing to bring your phosphate levels up?

My hypothesis is high nitrate will fuel algae bloom and when algae is growing it will suck up the phosphates .

 

[bcarl77]

I opened the bypass on my filter roller as well. Hoping this helps some, along with skimming very dry and decreasing the time the refug light is on.

 

[Potatohead]

I opened the bypass on my filter roller as well. Hoping this helps some, along with skimming very dry and decreasing the time the refug light is on.

I... May have forgotten mine had a bypass ;Facepalm. I probably should have done that for a couple months instead of removing it entirely. Oh well.

 

[Crustaceon]

I am well onboard with this trend of keeping phosphate levels closer to 0.1PPM. Unfortunately, I am having a hard time getting there. Was stuck at near 0 for several months, finally getting it to 0.04-0.05ppm...

Seachem Phosphorus. Dose and retest each day. You’ll probably have to do this for a week, but it’ll eventually stabilize where you want it.

 

[sailoracu2]

My phosphates are .07 I have been fighting cyno for months, there is no coraline growth. Should I bring P. Up to 1.0
Everything was tested yesterday dkh was 6.4 I'm bring this up, C. 478 M.1440 PH 8.3
I would appreciate any help.

 

[Crustaceon]

I’ve been trying to tell people this for years, I seldom post online now as people would argue blindly with me. My 8 year old reef tank only has a skimmer on a very dry setting. My phosphate is 1.5ppm and no3 goes from 20-80ppm depending on how much water changes I make. It’s all about balance, you will eventually want higher alk levels with your higher nutrient levels as the nutrients are acidic compounds. That said there is only a small difference with that sort of tank. If your ULNS everything has to be exact and any spikes are unforgiving. If you want to keep your Corals for a long time don’t starve let them have all the nutrients they want and you’ll also have a less stressful experience in the hobby.

I use the same strategy. We’re all told to reduce nutrients endlessly and see that in new skimmer designs, roller mats, etc. I give my tank what it needs first and foremost and THEN worry about excessive nutrients based on the response of my coral and any nuisance algae growth. It’s way too easy to over do it when it comes to nutrient reduction and this is why we see so many bleached or STN’d acros. Our tanks are not the ocean and NSW parameters only work for the ocean due to its pretty much endless volume. In a confined little box of water, there isn’t an endless stream of nutrients floating around. It gets used up very quickly and it’s much better to keep it “buffered” by elevating things like nitrates, phosphates, alk/cal/mg and trace.

 

[Crustaceon]

My phosphates are .07 I have been fighting cyno for months, there is no coraline growth. Should I bring P. Up to 1.0
Everything was tested yesterday dkh was 6.4 I'm bring this up, C. 478 M.1440 PH 8.3
I would appreciate any help.

I think you’re fine on that number. For reference, I run my tank at .08ppm phosphates. I think your issue here is a lack of biological competition to keep cyano under control. Typically, you’ll get cyano when nutrients (especially phosphates) bottom out. Maybe this happened at some point? This causes much of your tank’s beneficial bacteria to starve and allows cyano to gain a foothold. So what you can do is make sure you have at least 5ppm nitrates and .05ppm phosphates. Siphon out as much cyano as possible from your rocks and sand. Dose a beneficial bacteria supplement. Rinse and repeat daily, possibly for a week or two. Don’t be surprised if your water gets slightly “hazy”. That’s a good thing and indicates the bacterial population is rebounding.

 

[bcarl77]

Seachem Phosphorus. Dose and retest each day. You’ll probably have to do this for a week, but it’ll eventually stabilize where you want it.

Been using Tropic Marin's Plus NP. Finally starting to getting readings around .03-.04 after a few weeks of dosing. Shutting down the refugium is next.

 

[Crustaceon]

Been using Tropic Marin's Plus NP. Finally starting to getting readings around .03-.04 after a few weeks of dosing. Shutting down the refugium is next.

Yep. I had to do the same thing after chaeto pretty much sterilized my system. I figure the rock and sand needed to be saturated with Po4 before I started getting a stable reading.

 

[MabuyaQ]

My phosphates are .07 I have been fighting cyno for months, there is no coraline growth. Should I bring P. Up to 1.0
Everything was tested yesterday dkh was 6.4 I'm bring this up, C. 478 M.1440 PH 8.3
I would appreciate any help.

If you have cyano we already know you have phosphate, but the real question is do you have nitrate and how did it develop in the past. In most cases the bacteria and microalgae that compete with cyano have been starved of nitrate for an extended period of time with nitrates still being to low for them to reestablish.

 

[135zman]

Been using Tropic Marin's Plus NP. Finally starting to getting readings around .03-.04 after a few weeks of dosing. Shutting down the refugium is next.

@bcarl77 Can you share some background about using Tropic Marin Plus NP? Such as - what is does, why you started dosing it, do you have to be using a certain one of the four Tropic Marin salts or their ABC balling compounds? Thanks