Help - Carbon Dosing > PO4 bottomed out!

[Mark Barker]

Hi all,

I’m a fairly new Uk poster to the site so go easy on me

I’ve been dosing a DIY NoPox mixture of Vodka, Vinegar and RO for a fair few months now. When I started, NO3 was around 25/30ppm, PO4 0.04/0.07 and I was running a refugium. The core aim of the carbondosing, aside from other benefits, was to reduce NO3.

Between the carbon dosing and the refugium, PO4 depleted fairly quickly - so I took the refugium offline and removed the algae bed.

I had to dose a small amount of PO4 to maintain a decent level but it was a real issue at the time.

however, my NO3 has now dropped to an acceptable level between 5-10ppm but I can’t maintain any reading of PO4, it’s consistently zero on the Hanna ULR.

I have some mono-potassium phosphate, which I’ve been manually dosing to achieve a ‘desired’ level over the last week, and reduced the DIY NoPox accordingly - but still nothing!

Can’t help but think I’m getting myself in a middle now, and need to rectify before significant issues follow!

I’m not heavily stocked, so could add another small fish (reefer 170), but I would worry about that having a negative effect on the NO3?

All suggestions and recommendations are welcome!

Here’s a pic of the small money pit

 

[Dan_P]

Can you increase the PO4 dose to achieve the level you want?

 

[Mark Barker]

Can you increase the PO4 dose to achieve the level you want?

It’s a sound point, and something I’ve tried this week - just seems no matter how much I put in it’s gone the following day.

Dosed yesterday what should have increased from 0 to 0.07 (not the best move I know, but was an experiment of sorts to see what residual would remain). Result this morning - 0!

I know the Hanna is ok as getting a consistent reason on another system, with minor fluctuations. But this one has me stumped now!

 

[Dan_P]

It’s a sound point, and something I’ve tried this week - just seems no matter how much I put in it’s gone the following day.

Dosed yesterday what should have increased from 0 to 0.07 (not the best move I know, but was an experiment of sorts to see what residual would remain). Result this morning - 0!

I know the Hanna is ok as getting a consistent reason on another system, with minor fluctuations. But this one has me stumped now!

It sounds like your system needs PO4 and reaching a steady level could take weeks.

Before increasing the dosing frequency, confirm that the amount you add actually increases the PO4 concentration to what you calculated it should. Either dose the aquarium and measure the PO4 after an hour or two, or better yet, remove a sample of aquarium water, dose it with a proportionally smaller dose and measure the PO4 level.

 

[TomM]

What are you feeding your fish?

Aside from dosing you could consider a high quality flake/pellet food as they tend to have a much higher PO4 amount vs. frozen.

 

[Mark Barker]

It sounds like your system needs PO4 and reaching a steady level could take weeks.

Before increasing the dosing frequency, confirm that the amount you add actually increases the PO4 concentration to what you calculated it should. Either dose the aquarium and measure the PO4 after an hour or two, or better yet, remove a sample of aquarium water, dose it with a proportionally smaller dose and measure the PO4 level.

Stunning idea!

 

[2Wheelsonly]

Rocks new? Whenever my po4 goes nuts and bottoms out it’s when i add stuff like caribsea liferock... it sucks up the po4 big time and I have to dose for months

 

[Mark Barker]

Rocks new? Whenever my po4 goes nuts and bottoms out it’s when i add stuff like caribsea liferock... it sucks up the po4 big time and I have to dose for months

No mate, well - 12 months in August so not ‘mature’ as such. But minimal rock work really, and branching just not the caribsea kind (old school, bought from a fellow reefer dried out)

 

[PBar]

Hello,
just one small remark, if you are carbon dosing and also dosing phosphate... in my head seems that you are only “feeding“ more the bacterias as well.

My first reaction would be to decrease the carbon dosing and just wait. It take some time to balance it.

It is very plausible that your nitrate is also going down each day...

Let me know!
Cheers

 

[Mark Barker]

Hello,
just one small remark, if you are carbon dosing and also dosing phosphate... in my head seems that you are only “feeding“ more the bacterias as well.

My first reaction would be to decrease the carbon dosing and just wait. It take some time to balance it.

It is very plausible that your nitrate is also going down each day...

Let me know!
Cheers

Makes absolute sense and you’re likely correct! Yesterday I reduced the carbon dosage a little so will give it a couple of weeks to see how it reacts - in the meantime, dosing some PO4 to maintain an element within

 

[Randy Holmes-Farley Verified Community Expert]

It’s a sound point, and something I’ve tried this week - just seems no matter how much I put in it’s gone the following day.

Dosed yesterday what should have increased from 0 to 0.07 (not the best move I know, but was an experiment of sorts to see what residual would remain). Result this morning - 0!

I know the Hanna is ok as getting a consistent reason on another system, with minor fluctuations. But this one has me stumped now!

One thing's sure: there's a dose large enough to detect 24 h later, assuming your kit works and the product you are using actually contains soluble phosphate.

 

[Cjeippert]

What are you feeding your fish?

Aside from dosing you could consider a high quality flake/pellet food as they tend to have a much higher PO4 amount vs. frozen.

I add reef roids on a more frequent basis. Corals love it, and phosphates rise

 

[Uncle99]

I need to dose phosphate everyday to maintain adequate levels, without impacting my nitrates which I keep in line with Nopox.

keep hitting it till she shows on the meter.
Then measure the consumption over a week.
For me it was about 7ppb per day and 10ml of Neophos or Seachem Phosphorus in a 180g to hold phosphate at 0.07ppm.

It took a lot of product to raise it to 0.07ppm initially.