NO3 and PO4 chemistry

Herpdederp

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I have a question about NO3 and PO4 chemistry. Usually when PO4 drops NO3 would drop with it right? I've been having problems keeping PO4 up, so far I removed pellet reactor and disconnected the refugium. But as soon as I turn the fuge back on the PO4 drops too fast, is it possible that the micro algae is sucking up too much PO4 but not NO3?

I've been having issues since I went from no water changes to changing 10% weekly because I was not able to keep the trace elements in balance. It's been 2 months since I have started water changes. Tank is 2 years old.
 
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Herpdederp

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Not necessarily. Yes, the scenario you outline is possible (more phosphate consumption than nitrate). What’s the size of your tank, bio load (fish) and how much, how often (and what) do you feed.
When I started to do water changes I fed pellet food daily and frozen every 3-4 days and reef roids once a week.

I have two tanks, one big one small and they seem to be having the same problem, the big tank is 9 months old. Same feeding routine for both. I have more fish in the big tank so I feed a bit more which is why the NO3 is so high.

I managed to bump up the PO4 with NeoPhos but the PO4 gets drained instantly. I've tried to feed more but since the imbalance I've only been feeding 1/3 of what I was feeding before.

The big drop in the small tank on the latest test was when I turned the fuge back on. \

Been trying to diagnose the problem for a couple of weeks now @@

38gallon 138gallon
1659850176892.png
 

NowGlazeIT

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Adding phosphate is easy with reef roids. One level scoop adds around .03 po4 in my 120g system. Is the drop in po4 recent? Did you add anything new like dry rock?
 

NowGlazeIT

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When I started to do water changes I fed pellet food daily and frozen every 3-4 days and reef roids once a week.

I have two tanks, one big one small and they seem to be having the same problem, the big tank is 9 months old. Same feeding routine for both. I have more fish in the big tank so I feed a bit more which is why the NO3 is so high.

I managed to bump up the PO4 with NeoPhos but the PO4 gets drained instantly. I've tried to feed more but since the imbalance I've only been feeding 1/3 of what I was feeding before.

The big drop in the small tank on the latest test was when I turned the fuge back on. \

Been trying to diagnose the problem for a couple of weeks now @@

38gallon 138gallon
1659850176892.png
I think your no3 is rising because your po4 is limited. When these two are elevated you can bring them both down with carbon dosing.
 
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Herpdederp

Herpdederp

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I think your no3 is rising because your po4 is limited. When these two are elevated you can bring them both down with carbon dosing.
I have a bag of carbon in the filter system, would adding more help with decreasing No3?
 

NowGlazeIT

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Ahhh gotcha, I use NitraPhos Minus
Okay cool that’ll do the job. I recommend you up your reef roids feedings. Try to bump your po4 past the level of accuracy on your test kits. That way you know for sure they’re is at least some po4 for your nitrates to bind with
 
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Okay cool that’ll do the job. I recommend you up your reef roids feedings. Try to bump your po4 past the level of accuracy on your test kits. That way you know for sure they’re is at least some po4 for your nitrates to bind with
I stopped feeding reef roids since the unbalance, just made the no3 shoot up while po4 was at 0 lol. I use a po4 supplement to try and keep the balance
 

Randy Holmes-Farley

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I have a question about NO3 and PO4 chemistry. Usually when PO4 drops NO3 would drop with it right? I've been having problems keeping PO4 up, so far I removed pellet reactor and disconnected the refugium. But as soon as I turn the fuge back on the PO4 drops too fast, is it possible that the micro algae is sucking up too much PO4 but not NO3?

I've been having issues since I went from no water changes to changing 10% weekly because I was not able to keep the trace elements in balance. It's been 2 months since I have started water changes. Tank is 2 years old.

As a general rule, nitrate and phosphate are not strictly tied together since there are various processes that add or remove one and not the other.

A big reason for depleted phosphate relative to nitrate is binding of phosphate to rock and sand.
 

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Am dealing with the same issue now, happened about a month after installing the bucket chaeto fuge. I was only running it at night to help with the oxygen & ph. I ended up dosing .08 to .10 every night with neophos by the next morning (8hrs) phosphate was 0 with nitrates at 16. I lost 3 expensive acro's and gmk frag with the rest of the stix turned brown. Then came cyano cause of the imbalance. All my dumba** fault too everything was dialed in perfect. What I ended up doing besides throwing the fuge off the back porch is dosing microbacter7 daily for a few till po4 came up enough then dosed small amounts of biofuel. Nutrients are back to no3-16 , po4- .06 and no cyano for a week. Sticks are slowly coloring up and extending polyps so that's what worked for me.
 
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1661019408282.png

An update to my balancing issues. I've been dosing PO4 + and removed all micro algae, pellet reactor and turned off the skimmer permanently as well as removing 60% of the bio rings I had in both tanks, but without much improvement. I will try dosing bacteria baily to see if that makes a difference.
 

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1661019408282.png

An update to my balancing issues. I've been dosing PO4 + and removed all micro algae, pellet reactor and turned off the skimmer permanently as well as removing 60% of the bio rings I had in both tanks, but without much improvement. I will try dosing bacteria baily to see if that makes a difference.

I am in the same situation as you. Dosing bacteria and carbon dosing doesn't work because po4 is bottomed out (I reckon). My po4 is currently 0, was 6ppb last week (0.018ppm). Tried the above and no3 doesn't budge. My no3 has reached 42ppm and it's worrying.

Am currently trying to dose seachem flourish in to see if raising po4 works in reducing no3.
Fr some reason my corals looked better when po4 was 0.3 0.4. and I run no GFO or AC ever since I started the tank.
 

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