Reducing NO3 without dropping PO4???

[Steven9194]

Looking for advice on how to reduce NO3, without tanking my PO4. I have battled Dino’s and cyano in the past and DO NOT want to go through that battle again. After that battle I gave up on tracking numbers. My fish and soft corals have been doing great, but I would love to give other coral a try again.

Last week I tested my water at a shop and my NO3/PO4 were off the charts. Mag/ALK were low. Since, I’ve been dosing to raise Mag and ALK.

I have added a baseball sized amount of chaeto, running GFO and began carbon dosing 15ml a day. I have also done 3, 20% water changes.

Today the numbers are looking much better; however, the PO4 is dropping much quicker than the NO3.

125g

 

[eggie]

What Carbon Dosing method are you using ?

 

[Steven9194]

What Carbon Dosing method are you using ?

 

[Steven9194]

What Carbon Dosing method are you using ?

 

[eggie]

If its been working then keep it up it takes time to reduce nutrients by Carbon dosing and you dont want to rush it.
I would definetly take out the GFO because it could sink your phosphate as your using 2 methods for removing Po4.

If you unbalance your tank dinos and cyano could come back. You want to have a balance of Nitrates and Phosphate

 

[skey44]

I wouldn’t trust a spin test honestly. Hannah checkers FTW on nitrates and phosphates IMO.
Of your reduction methods carbon dosing and chaeto growth should remove proportionally more nitrate (balanced in ratio). Water changes will lower both equally. GFO only removes phosphates and can be hard on corals if phosphates are reduced too rapidly, sounds like you already know what happens if you hit zeroes.
Tell us a little more about your system. What are your husbandry goals? (Edit I see you want to try hard corals) What is the root issue of your high nutrients? Overstocking, over feeding, lack of regular maintenance, insufficient filtration? I would make sure you’re addressing these questions while actively working on removal/ binding/ dilution.
IMO the exact ratio in your tank doesn’t really matter (I have numbers I know work for me but I see numbers all over the place in a lot of successful tanks here). Just don’t bottom them out.

 

[Steven9194]

I wouldn’t trust a spin test honestly. Hannah checkers FTW on nitrates and phosphates IMO.
Of your reduction methods they will remove proportionally more nitrate except the GFO. It only removes phosphates.

I ended up picking up some Hanna checkers and they also showed high levels not as high as the spin, but the PO4 were over the readable limit. These tests are from Monday, the day after I did the first water change and two days after the spin test.

 

[Steven9194]

If its been working then keep it up it takes time to reduce nutrients by Carbon dosing and you dont want to rush it.
I would definetly take out the GFO because it could sink your phosphate as your using 2 methods for removing Po4.

If you unbalance your tank dinos and cyano could come back. You want to have a balance of Nitrates and Phosphate

I definitely don’t want to tank the PO4… and was running the minimum about of recommended GFO, along with carbon dose. I would leave it as everything seems fine that is already in the tank. But adding new coral doesn’t work. They keep dying.

So I’m trying to move slow here by hitting it from a few different angles at once. Even with all of these, the numbers don’t seem to be moving much.

 

[skey44]

I would stick with your course. These numbers can be stubborn to lower and just as hard to keep down.
Why do you think your numbers have gotten so high? How old is the tank? What size is it. What is the fish population like? Feeding regimen? Sorry I have a lot of questions.

 

[Steven9194]

I would stick with your course. These numbers can be stubborn to lower and just as hard to keep down.
Why do you think your numbers have gotten so high? How old is the tank? What size is it. What is the fish population like? Feeding regimen? Sorry I have a lot of questions.

The tank is just under 2 years old. About 5 months ago I battled 3 strains of Dino’s and cyano…. was a nightmare! After I got rid of those, I refused to keep my numbers down for a month or so, then I started a new job and just didn’t have time to keep up with everything. I started dosing all for reef, instead of doing water changes and hadn’t done my water tests in a while since everything in the tank was looking good.

I started to toss in some new coral and they all died. So I did the test and seen the results of my lack of care over the past few months. I was feeding frozen once a day. I have recently changed it to every other day.

125g tank
Sailfin tang 6”
Tennetti tang 4”
Tomini tang 5”
Half blacked mimic tang 2”
Mag Fox 6”
2 clowns
Longhorn boxfish
Melanurus Wrass
Pixie hawkfish
Bristle Starfish

 

[Randy Holmes-Farley]

Starting with phosphate of 1.2 ppm (if accurate), I don’t think there’s much chance of driving it too low any time soon as long as you are not using phosphate binders.

 

[Pistondog]

You'll be a while reducing the po4. You can dilute your tank water with fresh saltwater to get a reading if off scale of the hanna tester. This assumes fsw has no po4.
Po4 also binds to rock and substrate, so a water change will reduce nitrates proportionately, but not po4 as more will desorb(?) from rock afterwards.

 

[buruskeee]

Your PO4 is way high (fyi the Hannah maxes at 0.9). I wouldn’t worry about tanking PO4.

A big water change will help. 50% should cut your NO3 by 50% but I’d be more worried about your PO4. Unless you’re only looking to keep LPS and softies, you will struggle to have SPS thrive with high PO4.