Let's talk phosphate levels

[rishma]

How about I always ran my tank .01 and it was good, but now I run it at .16 and it looks better than ever! Sticks are growing faster if you ask me! Dirty water and higher alk is what I’m liking personally.

And metal halides. Old School trifecta!

 

[schooncw]

I have a heavily rocked LPS dominant system and my PO is at a constant 1.0.
Tho I have changed tanks, the system is 30 or so years old and I know the PO is bound in my rock. I run GFO 24/7, a packed bio pellet reactor, add Fauna Marin Bacto Energy every day and do regular water changes and still always 1.0 and NO3 around 45.
Although my corals look great, no nuisance algae, etc., the high PO really bothered me-hence the reactor, GFO-so I went the LAN route and it was the worst thing I ever did. I confess to going too quickly but my tank suffered when PO was 0.3 or so.
My solution was to stop the panic, keep on adding corals and fish and feeding as much as I ever did and rely on my eyes.

 

[Head Case]

I’m in the early stages of seeing benefits. My phosphates are definitely bound in the rock, as it is 7yrs old. GFO brought it from 2ppm to 0.5. Corals didn’t show much improvement and they definitely didn’t like the fines that came through. I’d turn the reactor off, they’d rebound a bit then phosphate would be right back at 0.5-1.0.

Next tried dosing Phosphate-e. Daily squirt of 2mL diluted into 50mL and slowly added to a 75gal tank. Took about a week but phosphate is below 0.1. Corals looking happier now but too early to tell.

 

[ElementReefer]

I might have to dose phosphate... No matter how much I feed, they're always 0. Tank is now 14 months old.
Any tips is welcome.

Reef Roids!

 

[Jimbo327]

I really don't think phosphates levels (obviously not zero) matter as much if you have a mature reef...the corals are soaking up the phosphates and there is little room for other bad stuff to grow since all the real estate is taken by corals But if you don't have a mature reef, then I think it is best to keep phosphates in the lower range as that is probably how most of your acquired corals are used to and discourages other bad things to grow on empty rocks.

My conception of low phosphates are shattered when I see gorgeous full SPS tanks that is running above 0.5ppm. Case in point, the recent TOTM winner is running phosphates at 0.5-0.66 (maxed out on his hanna tester). https://www.reef2reef.com/threads/reef-of-the-month-november-2024-aaronfreefs-sps-dream.1080686/

 

[Randy Holmes-Farley Verified Community Expert]

What I mean is that the phosphate kits to my understanding test PO4, as in phosphor binded to oxigen, but there might be other mixes with P, that organisms might be able to intake, while this would need probably millions invested.

I understand, and that is partly true, but not with the exact words you are saying. Corals do use organic forms of phosphate, of which there are many. Some hobby products add these. Tropic Marin has one.

All important forms of P in a reef tank (from an aquarist perspective) are phosphates of one sort or another. Some types are accurately tested by kit, while most kits will not detect any organic phosphates unless they specifically say they do. The Hach total P kit does so, but it involves a tedious digestion step.

ICP detects all forms of P. Since P by ICP is not regularly and greatly larger than phosphate by kit, we can assume that in reef tanks, these other forms are not dominating the total P pool (at least when microorganisms are removed before the ICP). Nevertheless, these other forms can form a large part of a coral diet (such as while bacteria and phytoplankton), and I referred to it in the first post of this thread:

Years ago we assumed that matching the ocean was desirable, but those levels seemed too low in practice (likely due to lack of particulate sources of P for corals in reef tanks)

The very, very few forms of P that are not phosphates (which still are not phosphorus) are phosphonic acids and phosphonates, such as 2-aminoethyl phosphonate.

The biological role of the natural phosphonates is still poorly understood.
which is from:
https://en.wikipedia.org/wiki/Phosphonate

 

[bezj]

Hi. Mixed reef tank. Lots of hammers/torches and SPS. Zero water changes. Use All For Reef, K element and Bacto Balance but also having to dose calcium nitrate otherwise nitrate would bottom out. Phosphate control by way of very minimal Elimi phos rapid dosed in reef matt. DKH c8. Phosphate 0.1-0.2 and nitrate 10-20. Excellent growth and colour. All going very well. Was always pretty relaxed if things sit within those ranges! Got very lazy re testing/zero testing for about 4+ months.
Noticed SPS growth slowed and lost an ahead or two on hammers/torches.

Tested Hanna phosphorus was blinking 200 and the blue was very dark so it must have been number three max of 0.61. Nitrate was 50+.

Corals definitely lost a bit of sparkle!

Have been gradually bringing P + N under control over the last 2 months.

Phosphate as of today 0.26 and nitrate 19.3.

Hammers/torches looking much better (have lost 5 or 6 heads on one torch alone and quite a few in hammers) and SPS looking better.

Prior to this blip the tank was definitely running rich but the corals looked great and I had nice fat fish!

As things are returning to what was the normal range everything is improving but I’ve definitely lost more SPS than LPS - STN or totally browned! The later might come back.

Looking back the corals were able to cope with high P + N levels but I think an Alkalinity blip sent the corals in to a spiral which pushed them over the edge - 8 DKH to 11.5 DKH over the course of a month that got me testing again! I dealt with this first by dropping levels by 0.1 per day max until I hit 9. And then started work on the N + P.

Moral of the story always do your testing!

 

[Faurek]

I understand, and that is partly true, but not with the exact words you are saying. Corals do use organic forms of phosphate, of which there are many. Some hobby products add these. Tropic Marin has one.

All important forms of P in a reef tank (from an aquarist perspective) are phosphates of one sort or another. Some types are accurately tested by kit, while most kits will not detect any organic phosphates unless they specifically say they do. The Hach total P kit does so, but it involves a tedious digestion step.

ICP detects all forms of P. Since P by ICP is not regularly and greatly larger than phosphate by kit, we can assume that in reef tanks, these other forms are not dominating the total P pool (at least when microorganisms are removed before the ICP). Nevertheless, these other forms can form a large part of a coral diet (such as while bacteria and phytoplankton), and I referred to it in the first post of this thread:

Years ago we assumed that matching the ocean was desirable, but those levels seemed too low in practice (likely due to lack of particulate sources of P for corals in reef tanks)

The very, very few forms of P that are not phosphates (which still are not phosphorus) are phosphonic acids and phosphonates, such as 2-aminoethyl phosphonate.

The biological role of the natural phosphonates is still poorly understood.
which is from:
https://en.wikipedia.org/wiki/Phosphonate

Thanks for adding to my knowledge. I still think we know very little to what probably is involved in the ocean so someone could actually replicate accurately, but always learning.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for adding to my knowledge. I still think we know very little to what probably is involved in the ocean so someone could actually replicate accurately, but always learning.

That is certainly true, and organics are the wild wild west in terms of understanding.

I know some folks are working to help understand organics more, but its too early to comment on that.

 

[Jasonak]

My phosphate is .5 and my corals never looked better.

 

[Randy Holmes-Farley Verified Community Expert]

My phosphate is .5 and my corals never looked better.

Just for clarity, better than when phosphate was lower, or higher?

 

[Jasonak]

Better than when phosphate were lower. BUT I just started dosing biofuel so im assuming that has something to do with it. My Phos normally runs around .2-.3
My NIT at 8

 

[Jasonak]

I did notice that my hammer corals do not seem as full. But every SPS in my tank has PE which it not the norm. I have some that always do but not every single one.

 

[moretor1]

Phosphates started extremely high ~4ppm and I couldn't keep anything alive. Once below 1.5ppm softies were growing and lps would stagnate until eventually dying
Under .25 I start getting coralline growth and lps growth
If it creeps over .3-.4 I can see the flesh on lps slowly recede and coralline will start dying off

 

[lbacha]

Great thread, years ago I was into high tech planted tanks and I feel that reef tank nutrient expectations are similar to the ones you had with those types of tanks. With planted tanks you had high light (I ran metal halides), CO2 injection (the alk of a planted tank), you dosed tons of nutrients (Nitrates, Phosphates and Potassium) and finally trace elements. The idea was that if none of these things ever became a limiting factor then the beneficial plants you were growing would out compete any algae (you used a CUC just like a reef tank, shrimp, snail, fish, etc). You didn't worry about how much of any of these things you provided other than making sure they were all in abundance.

If you let any of them deplete, nutrients, light, CO2, etc then your beneficial plants would die back and algae would take over. The main issue with this approach was the amount of work as you had to trim plants weekly and replant because they literally grew like weeds.

I consider high energy reef tanks to be the same. If you are pumping high par then you need to ensure you have enough nutrients, trace elements and instead of CO2 it is Alk/Cal/Mag that you need to keep stable. The nutrients are not what cause algae issues in my opinion it is lack of a CUC, not enough beneficial nutrient using organisms (coralline, coral, etc.) and trace element depletion. I know alot of people think water changes are all about export of bad things but in many tanks it is about replenishing trace elements.

This is all my opinion based on years of empirical evidence and seeing how similar the balancing act is in high energy planted tanks and reef tanks. My takeaway is focus on stability vs chasing high or low nutrients. In a reef tank we have lots of proof that swings in parameters will cause coral to stop growing. Once that happens the balance is broken which allows algae to get a foothold. You may have enough CUC and nutrient export when the coral is happy but when is stops consuming nutrients things will quickly get out of balance and algae can take over. I see post after post blaming this on nutrients but in reality it is because what was using the nutrients (your healthy coral) stopped using them so algae decided to be the beneficiary and your CUC couldn't keep up.

I also see alot of posts where people are in what they consider to be the ugly stage because they have algae issues (I personally don't consider green algae part of the ugly stage since it can happen at any point and once I see green algae growing I know my new tank is stabilizing). I think alot of people struggle because they don't start stabilizing alk/cal/mag soon enough therefore they are basically promoting algae growth with their high lights and nutrients vs promoting coralline and coral.

 

[mapman]

Thats how it is until you get the rock/sand saturated. I was dosing about .15ppm/day for a few weeks in my waterbox. The good news is i was able to grow SPS from essentially week 2 of a tank started with dead rock. Anything but 0s.

This is what happened to me. I'm still currently using phosguard to get the phosphates out of my sand/rock. I can get the phosphates down below .1 but once i take the phosguard out it gradually rises.

 

[JayM]

Reading all of the posts with the higher than "normal" phosphates has me thinking I might just let my GFO sit until it's exhausted and let the PO4 slowly do it's thing and see what happens. I'd be ecstatic if it can find it's own balance (if everything stays happy wherever it lands) and have one less thing for me to fuss with.

 

[Randy Holmes-Farley Verified Community Expert]

Reading all of the posts with the higher than "normal" phosphates has me thinking I might just let my GFO sit until it's exhausted and let the PO4 slowly do it's thing and see what happens. I'd be ecstatic if it can find it's own balance (if everything stays happy wherever it lands) and have one less thing for me to fuss with.

Where is it now?

Keep us updated!

 

[Rolliad]

My recent ICP showed i had a 3.6ppm phospate level. Yes, 3.6. I had no idea what my levels where because it kept maxing out all my kits which is why I did the ICP.

I've been using phosban-l for about a week here now, taking it slow. I'm still out of range of my test kits but my corals are starting to perk up and get better polyp extension already.

If my math is right, based on how much I'm dosing, I should be in range of my Hannah tester within the next 1-2 days.

 

[Discotu]

I have an sps heavy tank and there have been two events where I perceived a noticeable "boost" in my corals. 1st was when I added a Co2 scrubber to bring my ph up to mid 8s and second was when I added GFO. ICP showed my PO4 at 0.4 so that's when I added GFO that brought it down to about .2 I swear I started seeing more growth tips on my larger more established colonies. Again, I can't say for sure it was the GFO or if there was even a boost in growth but I looks like it. Separately, I also noticed what little cyano or diatoms I had also dissappeared.