False PO4 reading

[Griff]

using Hannah checker and PO4 reading is 0. I know it's higher than 0 because of the hair algea I have. This is a new package of reagent. Is it possible I received a bad batch?

 

[ReeferBee]

This is perfectly normal when you algae. The HA is sucking up the po4, hence why you have a reading of 0

 

[Griff]

I guess... In my opinion the hair algea isn't out of control I'll pull out as much as I can wait a day or two and retest. What should the PO4 of my tap be? Could I test that to confirm its not the reagent?

 

[Anirban]

Just check your tap water...

 

[ReeferBee]

I guess...

 

[Griff]

I tested about a month ago and it was .67 I brought it down to roughly .3 with phosphate sponges and phosguard. Is it possible the hair algae is there and just hasn't had a chance to clear up. I pulled a bunch out a week ago and it's back to where it was. So there must be some phosphate right?

 

[Lasse]

Check your PO4 in the morning (before the light turns on) and just before the light goes of. If your HA is sucking up your PO4 (or something else with photosynthesis) - you will see some PO4 in the morning but none before the light turns on (normally). Its a well known fact that HA can bring down the PO4 to zero (at least - you will read 0) as ReeferBee state

Sincerely Lasse

 

[Griff]

Great advice! I'll try that this weekend.

 

[Randy Holmes-Farley Verified Community Expert]

I tested about a month ago and it was .67 I brought it down to roughly .3 with phosphate sponges and phosguard. Is it possible the hair algae is there and just hasn't had a chance to clear up. I pulled a bunch out a week ago and it's back to where it was. So there must be some phosphate right?

Even zero on the Hanna can support algae, but that does not mean it is working correctly.

Also, there can be somewhat higher phosphate locally near the "roots" of the algae where organics may be degrading or the rock/sand is releasing phosphate, which might mostly be taken up before it gets away into the bulk water column.

 

[Richie Lloyd]

Hi hope you dont mind me chipping in
I have an algae issue which has been on going a loooong time
I have zero Nitrate and zero Phosphate
I have hair algae on my weir comb and a lot in my weir. My glass goes green every other day. My back glass gets a browny type algae on it within a few days of me cleaning it. The rocks are not too bad as cuc keep it relatively clean, certainly not hair algae everywhere like I have had in the past.
I have tried everything even to the point I thinking its from excess co2 from calcium reactor.
Lowish bioload. Feed very sparingly, lights only on 8 hours on bulbs under 6 months old (T5) Use phos reactor with zero effluent. Yet I have zero phosphates, even confirmed by Triton lab test.
My corals are very pale which I can only put down to zero nitrate, and the ones further down are duller (acans) im guessing as the phos is hidden and they are not pelted with light.

I read the above posts about testing in the dark.
Tested my display lights on Zero
Tested my sump in the dark 0.07 which is as high as I would want. SO I am guessing my whole tank is 0.07 but why the hell is it showing as zero from the display where my issues are happening.
I think I am on to something phosphate algae wise thanks to the above but I need to understand it more to fix the issue.

 

[Lasse]

I read the above posts about testing in the dark.
Tested my display lights on Zero
Tested my sump in the dark 0.07 which is as high as I would want. SO I am guessing my whole tank is 0.07 but why the hell is it showing as zero from the display where my issues are happening.
I think I am on to something phosphate algae wise thanks to the above but I need to understand it more to fix the issue.

A system there you do not use an organic carbon source have two different major phases of PO4 – production of PO4 by bacteria and uptake of PO4 of organism with photosynthesis. The production of PO4 happens all the time 7/24 and is rather constant (depended of biological load of the system) but the uptake by photosynthesis only happens when the light is on. Therefore will often PO4 levels rise during night (highest just before the light turns on) and after the lights has turned on – the consumption of PO4 will rise and sooner or later be higher than the production and the PO4 levels will decline – sometimes to 0 -> the system is PO4 limited. In systems with no organic carbon dosage you should normally have a pending level of PO4 – highest in the morning and lowest in the afternoon.

If you do not have this fluctuations of PO4 – probably some other nutrients are limited (normally nitrogen but also iron limitation are commonly found) or you do not have any photosynthesis (rather unlikely)

In a system with organic carbon dosage and effective skimmers/filters you will have some consumptions (and exporting) of PO4 even during night but normally you will have some fluctuations even in these systems. If you don´t – check if there is some other limited factors like lack of nitrogen (NH4/NO2/NO3)

If you have a constant level of PO4 for the whole 24 hours period – do some testing with adding NO3 to the DT and measure the PO4 level. If it drops a couple of hours after the addition (the light must be on during the test) – you probably have a NO3 limited system of growth. I have use this method several times for validate a lack of nitrogen. With the type of low level photospectrometers (like Hanna) we have today – it’s possible to do this way to valid a nitrogen limited system.

Sincerely Lasse

 

[Richie Lloyd]

Thank you for that reply, very interesting and very well written if your first language is Swedish?
Yes I use a Hanna Phosphorous meter.
SO, sorry what do you mean 'you probably have a NO3 limited system of growth?

 

[Lasse]

@Richie Lloyd Yes my first language is Swedish but I know how to use both MS word (spelling) and google translate (sometimes) . The problem of writing in English instead of Swedish is that the word sequence is different in English compared with Swedish (and we love small words in order to show our emphasis). I had my first English lecture in 6th grade (back in 1966) nowadays they start in 3th grade (9 years old)

My fault – I meant a nitrogen limited system – with other words – there is too little available nitrogen compared with available phosphorus in order to get optimal growth of bacteria (that use inorganic nitrogen or phosphorus in order to build biomass) or growth of organism using photosynthesis (always use inorganic N and P) The most common forms of inorganic substances for building more biomass -> P is PO4 – and for N it´s mostly NO3 (for some algae NH4/NH3)

With other words - If you read a constant PO4 (not 0) level during the day cycle and if you get a lower reading after adding NO3 - it was the lack of N that hinder your organisms to take up more P and lower the level of PO4. You have to repeat the readings for some days and also do some readings without adding NO3 to be sure - but is often possible to use this method in order to be sure that your N is limited in order to bring down the PO4 with biological methods

In your case - it’s probably the algae that consume your N and P and I think that you have to combats them with some grazers (I love urchins) or mechanical removing in order to take down the biomass and leave some P and N for your corals. I´m also think that’s you are right if you suspect high CO2 levels will favour the algae. Test to bring up the pH (with a good skimmer or gas exchanger) and use outside air or a CO2 scrubber to the skimmer air intake. Lime water can help also.

Sincerely Lasse

 

[Richie Lloyd]

OK I understand all that! A couple of things for me to think about then. I think one of the things mentioned there about the skimmer intake outside. I cannot get it outside but I could get it outside of my sump cupboard. The warm moist air cannot be good for the skimmer?

I am English living in England, my cousin lives in Switzerland with her husband, seems most european countries speak better English than the English LOL

 

[Richie Lloyd]

Pic from a few months ago

 

[Randy Holmes-Farley Verified Community Expert]

Hi hope you dont mind me chipping in
I have an algae issue which has been on going a loooong time
I have zero Nitrate and zero Phosphate
I have hair algae on my weir comb and a lot in my weir. My glass goes green every other day. My back glass gets a browny type algae on it within a few days of me cleaning it. The rocks are not too bad as cuc keep it relatively clean, certainly not hair algae everywhere like I have had in the past.
I have tried everything even to the point I thinking its from excess co2 from calcium reactor.
Lowish bioload. Feed very sparingly, lights only on 8 hours on bulbs under 6 months old (T5) Use phos reactor with zero effluent. Yet I have zero phosphates, even confirmed by Triton lab test.
My corals are very pale which I can only put down to zero nitrate, and the ones further down are duller (acans) im guessing as the phos is hidden and they are not pelted with light.

I read the above posts about testing in the dark.
Tested my display lights on Zero
Tested my sump in the dark 0.07 which is as high as I would want. SO I am guessing my whole tank is 0.07 but why the hell is it showing as zero from the display where my issues are happening.
I think I am on to something phosphate algae wise thanks to the above but I need to understand it more to fix the issue.

I would just clarify one idea: algae is not "caused" by any one thing. It needs ALL of adequate N, P, CO2, light, sufficient freedom from herbivores, a place to grow, and a variety of trace elements.

Take ANY one of those away (to a low enough level), and you can deter algae. A huge excess of most of them does not help algae much if any are missing.

 

[Griff]

Left lights off for 24 hours and retested still getting 0.

On another note I thought my bird of paradise was bleaching because of the high PO4 but when I got home from work today I found my emerald crab munching on him! Tried to catch him to throw him in the sum but he got away.

 

[Griff]

Maybe the phosguard and phosguard sponges sucked it all up along with the hair algae. Next time do a water change I'll get to scrubbing the rock in the waste water.

 

[Lasse]

Just to be sure - try to check your Hannas readings and validate that it works well. I would expect a readable rise of the PO4 after 24 hours without light. It’s possible that you in reality have 0 but in my experiences – it is seldom happens. Do you have a very “clean” (according to organic load) aquarium?


Sincerely Lasse

 

[Griff]

I only have 3 fish. And skimmer hasn't been pulling much if anything.