phosphate questions

[epsteino]

Can someone please give me some good references on what I can expect to see with different phosphate levels? What happens to SPS in high phosphate levels? what happens to them in low phosphate levels? What happens to phosphate throughout the day? does it swing in some sort of sine wave? Does it spike with feeding, especially smaller coral foods and what is the effect of that? I am trying to get a better idea of why my corals are not doing "well". maybe even struggling. I suspect it may have something to do with how I address phosphate?

Thanks

 

[Gareth elliott]

This is really tank dependent tbh, but generally speaking.

At 0 or undetectable can lead to corals being outcompeted by micro algae like dinoflagellates or cyanobacteria. Can also inhibit growth.

Less than .1ppm above 0 is usually where you want phosphate where in this range your tank finds happiness will be tank specific.

above .1ppm many people fight algae outbreaks, but not all.

somewhere around .2ppm(if I remember correctly) calcification inhibition starts to occur.

Very rough guide to phosphate

heres a more in depth look

http://reefkeeping.com/issues/2006-09/rhf/index.php

 

[Quietman]

Good reference to read.

I believe if you have higher ALK, above 8.5 or 9.0 you'll see some burnt tips as well if you maintain very low nutrients.

Interesting question on daily cycles of po4 rates with feeding. Don't think I've seen that data. But probably tough to measure as po4 can also bind to carbonate in rock and then release back into water so there are indirect sources as well.

As long as your removal/capture equals the production rate you'll have a steady level overall and the higher or lower production rates during the day really don't matter.

 

[Lasse]

You will have bacteria produce PO4 all day but only consumption when there is a photosynthetic process taking place. If you do not run a reversed refuge - you will have a rise during the dark hours and a decline in the light hours.

Sincerely Lasse

 

[Randy Holmes-Farley Verified Community Expert]

You will have bacteria produce PO4 all day but only consumption when there is a photosynthetic process taking place. If you do not run a reversed refuge - you will have a rise during the dark hours and a decline in the light hours.

Sincerely Lasse

Have you actually observed that swing in a reef tank? It would surprise me if one could.

 

[epsteino]

This is really tank dependent tbh, but generally speaking.

At 0 or undetectable can lead to corals being outcompeted by micro algae like dinoflagellates or cyanobacteria. Can also inhibit growth.

Less than .1ppm above 0 is usually where you want phosphate where in this range your tank finds happiness will be tank specific.

above .1ppm many people fight algae outbreaks, but not all.

somewhere around .2ppm(if I remember correctly) calcification inhibition starts to occur.

Very rough guide to phosphate

heres a more in depth look

http://reefkeeping.com/issues/2006-09/rhf/index.php

Thank you. That’s what I’m looking for. My phosphates are not that far off 0.1 at their max. Can be down in the 0.02 range too.

 

[epsteino]

Good reference to read.

I believe if you have higher ALK, above 8.5 or 9.0 you'll see some burnt tips as well if you maintain very low nutrients.

Interesting question on daily cycles of po4 rates with feeding. Don't think I've seen that data. But probably tough to measure as po4 can also bind to carbonate in rock and then release back into water so there are indirect sources as well.

As long as your removal/capture equals the production rate you'll have a steady level overall and the higher or lower production rates during the day really don't matter.

I believe the answer though to this question will give us a better understanding of how and when to run phosphate binders. Do we export phosphate during the night and let it accumulate during the day.

 

[epsteino]

R

Have you actually observed that swing in a reef tank? It would surprise me if one could.

Randy I have been testing my phosphates at different times and yes I am noticing this in my tank. Right before the lights go on I am getting 0.1 ppm. When the lights turn off I am at 0.2-3 ppm. What would you expect the phosphate levels to do during a 24 hour photo period. In addition I would expect the nitrate levels to fluctuate in the same manner. Not sure how this phosphate sink works here though. Would that keep phosphate at a constant if the rocks are not saturated? I believe my rocks must be saturated cause I’ve never run binders.

 

[Lasse]

Have you actually observed that swing in a reef tank? It would surprise me if one could.

Actually - I have done that. I had a tank that was total overgrown of softies - you could not see any "clean" rocks. I saw a change around 0,05 - 0.08 between morning (before light on) and evening (after light out). The average PO4 concentrations was around 0.4 ppm. I did this for more than 2 weeks and use a professional DR 2000 Spectrophotometer and after that - I repeat the testing now and then with the same results. I had use that spectrophotometer in my job on a daily schedule for many years at that time.

And it is not very surprising because the mineralising process by heterotrophic bacteria take place 7/24 (the production) but the consumption (phototrophic take up) mainly take place during the light period. In a stable pH (above 8) the fastest chemical bound-rebound process of PO4 I know (forming and dissolving of calcium phosphate) is rather slow IMO. This with a higher PO4 level during mornings was also a well known fact among many freshwater plant aquarists before the development of the PMDD method

For the moment - I have a very confused experiences with my aquarium and PO4 levels. I run a reversed refuge and a reversed flow DSB (thick undergravel filter with reversed flow). I´m not convinced that I can trust my Hanna HI-774 or/and my own testing routines because I get a rather huge variation of my PO4 readings and they have been around 3 - 4 times higher compared with TRITON the latest 4 TRITON tests I have done. However - I can see a pattern - but not that one I had expected . It is also rather complicated because in this low concentrations the Hi-774 accuracy (plus-minus 0.02 ppm) is a problem if the variations are small. I need a lot of measurements in order to understand. I have not access to my DR 2000 any longer and need to do the measurements with my HI-774. I´m not interested to know the exactly values - but only to see if I can establish a pattern that repeat itself. For the moment - there is 125 package of PO4 reagents waiting for me in the post office - I planning to run a serie of tests for a couple of days - probably every 4 hour and with 2 duplicates and see what I get

. Right before the lights go on I am getting 0.1 ppm. When the lights turn off I am at 0.2-3 ppm.

Is it a typo? I would expect a lower reading when light turns off - in your case 0.02-0.03. If it not a typo - do you have a reversed refuge?

Sincerely Lasse

 

[Dan_P]

Actually - I have done that. I had a tank that was total overgrown of softies - you could not see any "clean" rocks. I saw a change around 0,05 - 0.08 between morning (before light on) and evening (after light out). The average PO4 concentrations was around 0.4 ppm. I did this for more than 2 weeks and use a professional DR 2000 Spectrophotometer and after that - I repeat the testing now and then with the same results. I had use that spectrophotometer in my job on a daily schedule for many years at that time.

And it is not very surprising because the mineralising process by heterotrophic bacteria take place 7/24 (the production) but the consumption (phototrophic take up) mainly take place during the light period. In a stable pH (above 8) the fastest chemical bound-rebound process of PO4 I know (forming and dissolving of calcium phosphate) is rather slow IMO. This with a higher PO4 level during mornings was also a well known fact among many freshwater plant aquarists before the development of the PMDD method

For the moment - I have a very confused experiences with my aquarium and PO4 levels. I run a reversed refuge and a reversed flow DSB (thick undergravel filter with reversed flow). I´m not convinced that I can trust my Hanna HI-774 or/and my own testing routines because I get a rather huge variation of my PO4 readings and they have been around 3 - 4 times higher compared with TRITON the latest 4 TRITON tests I have done. However - I can see a pattern - but not that one I had expected . It is also rather complicated because in this low concentrations the Hi-774 accuracy (plus-minus 0.02 ppm) is a problem if the variations are small. I need a lot of measurements in order to understand. I have not access to my DR 2000 any longer and need to do the measurements with my HI-774. I´m not interested to know the exactly values - but only to see if I can establish a pattern that repeat itself. For the moment - there is 125 package of PO4 reagents waiting for me in the post office - I planning to run a serie of tests for a couple of days - probably every 4 hour and with 2 duplicates and see what I get


Is it a typo? I would expect a lower reading when light turns off - in your case 0.02-0.03. If it not a typo - do you have a reversed refuge?

Sincerely Lasse

Do you trust Triton’s PO4 results more than those of the Hanna Checker?

 

[Lasse]

TRITON is my standard and corresponds very well to how my corals thrive.

My Hanna - HI - 774 - show 0.07 - 0.1. Cyano and no growth. TRITON show 0.02. Rise my to 0.12 (HI-774) TRITON show 0.04. After a couple of weeks - growth very good and Cyano on the defensive.

Sincerely Lasse

 

[epsteino]

Actually - I have done that. I had a tank that was total overgrown of softies - you could not see any "clean" rocks. I saw a change around 0,05 - 0.08 between morning (before light on) and evening (after light out). The average PO4 concentrations was around 0.4 ppm. I did this for more than 2 weeks and use a professional DR 2000 Spectrophotometer and after that - I repeat the testing now and then with the same results. I had use that spectrophotometer in my job on a daily schedule for many years at that time.

And it is not very surprising because the mineralising process by heterotrophic bacteria take place 7/24 (the production) but the consumption (phototrophic take up) mainly take place during the light period. In a stable pH (above 8) the fastest chemical bound-rebound process of PO4 I know (forming and dissolving of calcium phosphate) is rather slow IMO. This with a higher PO4 level during mornings was also a well known fact among many freshwater plant aquarists before the development of the PMDD method

For the moment - I have a very confused experiences with my aquarium and PO4 levels. I run a reversed refuge and a reversed flow DSB (thick undergravel filter with reversed flow). I´m not convinced that I can trust my Hanna HI-774 or/and my own testing routines because I get a rather huge variation of my PO4 readings and they have been around 3 - 4 times higher compared with TRITON the latest 4 TRITON tests I have done. However - I can see a pattern - but not that one I had expected . It is also rather complicated because in this low concentrations the Hi-774 accuracy (plus-minus 0.02 ppm) is a problem if the variations are small. I need a lot of measurements in order to understand. I have not access to my DR 2000 any longer and need to do the measurements with my HI-774. I´m not interested to know the exactly values - but only to see if I can establish a pattern that repeat itself. For the moment - there is 125 package of PO4 reagents waiting for me in the post office - I planning to run a serie of tests for a couple of days - probably every 4 hour and with 2 duplicates and see what I get


Is it a typo? I would expect a lower reading when light turns off - in your case 0.02-0.03. If it not a typo - do you have a reversed refuge?

Sincerely Lasse

Sorry, yes it was a typo. I am reading 0.1 before lights go on and 0.02-0.03 when the lights go out. I do not run a refugium. I have started to run some rowaphos since I have been worried about higher phosphate spikes. But I still see a shift from morning to night.

so your swings are the same as mine?
What is your take on adding food and phosphate spikes ?

 

[Lasse]

IMO - I would not run GFO in that case. You have enough PO4 for your corals - it is not the left over that is important - it is the flux. If your corals looks good - just stay put. If you read low figures during morning - that´s another question - in that case - there is not much left for your corals during the light period. May I ask for your pH swing also - what´s the pH before the light turn on and what is it when it turns of (or what is the max during day) ?

so your swings are the same as mine?

That´s my new problem - it is not. But I´m running a reversed refuge. I have seen tendency to be more in the evening compared with the morning. It make no sense. I have to investigate this to calm my own mind

Sincerely Lasse

 

[Dan_P]

TRITON is my standard and corresponds very well to how my corals thrive.

My Hanna - HI - 774 - show 0.07 - 0.1. Cyano and no growth. TRITON show 0.02. Rise my to 0.012 (HI-774) TRITON show 0.04. After a couple of weeks - growth very good and Cyano on the defensive.

Sincerely Lasse

OK thanks Lasse.

 

[Lasse]

OK thanks Lasse.

Notice my typo - it was from the beginning 0.012 - is now and should be 0.12 ppm

Sincerely lasse

 

[epsteino]

IMO - I would not run GFO in that case. You have enough PO4 for your corals - it is not the left over that is important - it is the flux. If your corals looks good - just stay put. If you read low figures during morning - that´s another question - in that case - there is not much left for your corals during the light period. May I ask for your pH swing also - what´s the pH before the light turn on and what is it when it turns of (or what is the max during day) ?


That´s my new problem - it is not. But I´m running a reversed refuge. I have seen tendency to be more in the evening compared with the morning. It make no sense. I have to investigate this to calm my own mind

Sincerely Lasse

I’m not sure why I shouldn’t run gfo? Doesn’t it bring it down some? Of course I don’t want to take it all away but I’m sure I have enough stores in the rocks And bacterial turnover that it is never zero. I

the two curves are of my ph last week and then as of three days ago I started dosing alk only at night.

 

[Lasse]

Can you please publice a photo of your tank. I want to see how dense your coral population are and what type of corals you have. Do you still see the same pH swing after you start dosing alk only at night? The formation and dissolution of calcium phosphate is pH dependent - higher pH formation - lower pH dissolution. However - uncertain if your 0.4 in pH swing before could result in a loss of around 0,08 ppm during day. If formation/dissolution is the answer (or partly the answer) - you would (IMO) see a lesser swing in phosphate nowadays.

Apparently - if your observations is real - your system cycle around 0.07 ppm PO4 a day - for me it is more an indication of risk for PO4 starvation (0.02 is way to low IMO).

Sincerely Lasse

 

[Dan_P]

R

Randy I have been testing my phosphates at different times and yes I am noticing this in my tank. Right before the lights go on I am getting 0.1 ppm. When the lights turn off I am at 0.2-3 ppm. What would you expect the phosphate levels to do during a 24 hour photo period. In addition I would expect the nitrate levels to fluctuate in the same manner. Not sure how this phosphate sink works here though. Would that keep phosphate at a constant if the rocks are not saturated? I believe my rocks must be saturated cause I’ve never run binders.

How are you measuring PO4? Would you post a table of the time and levels? Thanks

 

[epsteino]

How are you measuring PO4? Would you post a table of the time and levels? Thanks

I’ve been testing phosphate once before my lights are on and then once when my lights turn off. Nothing more than that so I don’t have a real curve. All I know is that it measures 0.1 in the morning right before lights on and then 0.00-0.02 at night when the lights turn off.

 

[epsteino]

Can you please publice a photo of your tank. I want to see how dense your coral population are and what type of corals you have. Do you still see the same pH swing after you start dosing alk only at night? The formation and dissolution of calcium phosphate is pH dependent - higher pH formation - lower pH dissolution. However - uncertain if your 0.4 in pH swing before could result in a loss of around 0,08 ppm during day. If formation/dissolution is the answer (or partly the answer) - you would (IMO) see a lesser swing in phosphate nowadays.

Apparently - if your observations is real - your system cycle around 0.07 ppm PO4 a day - for me it is more an indication of risk for PO4 starvation (0.02 is way to low IMO).

Sincerely Lasse

The ph swing tightened up. Before running at night it had a 0.4 swing. Now it swings tighter at 0.2 swing. I’m happier with it now between 8.15 and 8,35. Before the alk change it swung from 8.00 to 8.45.