Phosphate and nitrates

salty105

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Help!

For the life of me I cannot keep my nitrates and phosphates from tanking.

I used to have a 20 gal reef tank and the nitrates and phosphates would not come up with just feeding and bio load so I had to dose. I chalked it up to not having a lot of fish in there seeing it was just one goby And 3 coral frags. This ended up in a giant dyno outbreak.

I have since upgraded to a 100 gal system with
2 clowns
2 dispar anthias
4 green chromis
And my trusty watchman with his pistol

The tank is 2 months old now and the nitrates and phosphates are steadily decreasing. I’m not doing any water changes and the only filtration I got going is filter socks.

20261007_173319_3B91C5A2-BBB9-4F6E-8BE0-1799E59A0426.png

These are my levels as of today. I’ve been working getting magnesium and calcium up (I just started testing for those last week) and I’m also slowly raising my salinity to 1.026

I have an auto feeder feeding three times a day and I supplement with either fish eggs or mysis shrimp once a day.

What am I doing wrong?
 
As things grow in a new tank they will use more nutrients than an established tank. Could be what you are seeing.
 
You're doing nothing wrong; your tank is just using up the available calc, mag., N and P.
Its not unusual to have to dose N and P; I do both. I use ammonium carbonate for N and TriSodium Phosphate for P.

You dont have enough fish in there yet for feeding to make a difference.
 
You're doing nothing wrong; your tank is just using up the available calc, mag., N and P.
Its not unusual to have to dose N and P; I do both. I use ammonium carbonate for N and TriSodium Phosphate for P.

You dont have enough fish in there yet for feeding to make a difference.
Ok thank you! Can I expect some of these nutrients to level out or should I expect to keep dosing? I just don’t think I have enough coral to drain mag and calc it’s literally like 5 small frags. I’ll start dosing nitrate and phos again tho!
 
If you raise the salinity to the ocean average of 35 ppt (sg = 1.0264), both calcium and magnesium will rise by about 10%.
 
If you raise the salinity to the ocean average of 35 ppt (sg = 1.0264), both calcium and magnesium will rise by about 10%.
Perfect that’s what I’m working on first before dosing too much calc and mag. Thanks
 
If you do have to start dosing to keep N and P detectable I've had very good luck with ammonium bicarb and diy phosphate using Randy's recipe. I've had to dose my SPS tank since starting it 3 years ago to keep N and P detectable. I've never tested mag 😉
 
If you do have to start dosing to keep N and P detectable I've had very good luck with ammonium bicarb and diy phosphate using Randy's recipe. I've had to dose my SPS tank since starting it 3 years ago to keep N and P detectable. I've never tested mag 😉
Perfect I’ll do that! And yeah fair enough I never did in my last tank and everything did fine. Guess the lfs guy just got me convinced to buy the test kit and then the mag supplement 🥲
 
Perfect that’s what I’m working on first before dosing too much calc and mag. Thanks

I’m also suspicious that the magnesium is not as low as you think. Mag tests are so inaccurate that I do not recommend them, and a 100 ppm drop in magnesium by consumption cannot happen without at least a thousand ppm of calcium being consumed the same way.
 
Perfect that’s what I’m working on first before dosing too much calc and mag. Thanks

I’m also suspicious that the magnesium is not as low as you think. Mag tests are so inaccurate that I do not recommend them, and a 100 ppm drop in magnesium by consumption cannot happen without at least a thousand ppm of calcium being consumed the same way.
Gotcha, I thought it may have been because the tank is only two months old and I used uncured dry rock for it. And maybe it was absorbing some of those elements. My alk was also very low in the beginning which I have fixed now. I know for a fact I don’t have enough coral to be consuming these elements so could it be something else? Or just salinity is low and my mag tests bad? My calcium is also really low.

I’m using the instant ocean purple, I’m planning on testing fresh salt water and seeing if that was the issue. And when I run out the salt I got I’m switching to another brand.

I’m not overly concerned about the levels at the moment seeing most the coral I got is doing just fine. Except my nepthea is struggling which I guess could be because of that.
 
Help!

For the life of me I cannot keep my nitrates and phosphates from tanking.

I used to have a 20 gal reef tank and the nitrates and phosphates would not come up with just feeding and bio load so I had to dose. I chalked it up to not having a lot of fish in there seeing it was just one goby And 3 coral frags. This ended up in a giant dyno outbreak.

I have since upgraded to a 100 gal system with
2 clowns
2 dispar anthias
4 green chromis
And my trusty watchman with his pistol

The tank is 2 months old now and the nitrates and phosphates are steadily decreasing. I’m not doing any water changes and the only filtration I got going is filter socks.

20261007_173319_3B91C5A2-BBB9-4F6E-8BE0-1799E59A0426.png

These are my levels as of today. I’ve been working getting magnesium and calcium up (I just started testing for those last week) and I’m also slowly raising my salinity to 1.026

I have an auto feeder feeding three times a day and I supplement with either fish eggs or mysis shrimp once a day.

What am I doing wrong?
Not sure I see the problem. Ca and KH is just to dose, you dont have to bother why its consumed, its just to dose so it keeps steady. In a unmature tank KH can be "consumed" more than Calcium, so you may have to dose KH/Ca NOT in 1/1 ratio but some more KH.

Nitrate is perfect value and if its going lower to zero its not a problem. Nitrate itself is never beneficial, rather the opposite, specially in high values. Its just an indicator if the nitrogen cycle is mature. The lower No3 the better becaus that means denitrification has same speed as nitrification=N cycle is stable and tank can process all N that comes into the system. The zooxanthellee in the corals need inorganic nitrogen but they prefer ammonium, so even if NO3 is very low, its not same as the zooxanthelle i suffering N deficiency, as ammonium exists thanks to fishes, and bacterial mineralisation. Only if you can establish the zooxantheller is starving from N, I would dose nitrogen in form ammonium or urea. And how do you know if a zooxanthelle/coral is starving from Nitrogen? (without send a sample of total Nitrogen to a lab). Here is a simple way for me:
If all these 3 things are at same time:
1) pale coral
2) No PO4 deficiency (like PO4 at least above 0.02)
3) very low No3
THEN coral may suffering N deficiency (not common).

The Po4 is too low, and too low PO4 is dangerous as there is no other option for the zooxanthelle to get inorganic phosphorus than via PO4. I would in first place feed fishes more and with froozen food, then you will feed both fish and zooxanthelle as frozen food contains quite much Po4, if that doesnt help enough dose some PO4, but carefully and just so you never goe below 0.02 ish.

Jonas
 
Help!

For the life of me I cannot keep my nitrates and phosphates from tanking.

I used to have a 20 gal reef tank and the nitrates and phosphates would not come up with just feeding and bio load so I had to dose. I chalked it up to not having a lot of fish in there seeing it was just one goby And 3 coral frags. This ended up in a giant dyno outbreak.

I have since upgraded to a 100 gal system with
2 clowns
2 dispar anthias
4 green chromis
And my trusty watchman with his pistol

The tank is 2 months old now and the nitrates and phosphates are steadily decreasing. I’m not doing any water changes and the only filtration I got going is filter socks.

20261007_173319_3B91C5A2-BBB9-4F6E-8BE0-1799E59A0426.png

These are my levels as of today. I’ve been working getting magnesium and calcium up (I just started testing for those last week) and I’m also slowly raising my salinity to 1.026

I have an auto feeder feeding three times a day and I supplement with either fish eggs or mysis shrimp once a day.

What am I doing wrong?
Not sure I see the problem. Ca and KH is just to dose, you dont have to bother why its consumed, its just to dose so it keeps steady. In a unmature tank KH can be "consumed" more than Calcium, so you may have to dose KH/Ca NOT in 1/1 ratio but some more KH.

Nitrate is perfect value and if its going lower to zero its not a problem. Nitrate itself is never beneficial, rather the opposite, specially in high values. Its just an indicator if the nitrogen cycle is mature. The lower No3 the better becaus that means denitrification has same speed as nitrification=N cycle is stable and tank can process all N that comes into the system. The zooxanthellee in the corals need inorganic nitrogen but they prefer ammonium, so even if NO3 is very low, its not same as the zooxanthelle i suffering N deficiency, as ammonium exists thanks to fishes, and bacterial mineralisation. Only if you can establish the zooxantheller is starving from N, I would dose nitrogen in form ammonium or urea. And how do you know if a zooxanthelle/coral is starving from Nitrogen? (without send a sample of total Nitrogen to a lab). Here is a simple way for me:
If all these 3 things are at same time:
1) pale coral
2) No PO4 deficiency (like PO4 at least above 0.02)
3) very low No3
THEN coral may suffering N deficiency (not common).

The Po4 is too low, and too low PO4 is dangerous as there is no other option for the zooxanthelle to get inorganic phosphorus than via PO4. I would in first place feed fishes more and with froozen food, then you will feed both fish and zooxanthelle as frozen food contains quite much Po4, if that doesnt help enough dose some PO4, but carefully and just so you never goe below 0.02 ish.

Jonas
Very informative thank you!!
 

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