How to raise phosphate and nitrate?

[Mark Waltermire]

Hello everyone,

I struggle with the problem that many people wish they had. I cannot get my nitrates or phosphate to be detectable using the salifert test kit for nitrate, and the phosphate checker for phosphate. The phosphate checker always reads 0.00, and the nitrate test kit seems to never show any color. The tank is a 72 gallon, with about 10 gallons worth of water in the sump. In terms of livestock I have two black-and-white clown fish, a giant maroon clown fish, purple tank, lawnmower money, and clown Goby. I feed the tank one cube of PE Mysis every day (not rinsed), as well as usually flakes in the morning, and Nori for the tang when I remember.

For nutrient extraction I have a skimz SK181, that is set to skim about as dry as possible, only gathering about.75" of skim mate every month. The skimmers also only set to run for 13 hours a day. I do not run carbon or GFO. I do water changes about every 2 to 4 weeks, and try to change out about 10 gallons when I do them. The tank has only been set up for about six months, and I did run GFO for about the first two months.

I do have a Triton test and that is currently in the mail to be analyzed, but it is my understanding that that would not tell me anything about nitrate or phosphate. The tank is a mix of SPS and LPS, and they both seem to grow pretty well.

The main reason for asking is I just got a Maxima clam, and don't want him to die from a lack of nutrients in water. I suppose, that if the SPS is growing then the clam will be okay. Let me know if this is correct reasoning or if I should worry.

 

[DLHDesign]

You could (in theory) dose in a food-grade phosphate if desired, but that seems pretty extreme...

Normally I'd suggest reducing your skim time, but you're already on the low end of the scale, I feel. My inclination is to suggest a slightly heavier feeding level, but that could just as easily create more problems than it solves... Let's check with the #reefsquad to see if anyone has anything better to offer you.

 

[saltyfilmfolks]

If your corals are all fine I’d say you’re fine.
Make sure that clam gets plenty of light. They come from a low nutint ocean and make their own foods.

You may be ULNS , but it’s been done a lot.
You could add some sponge powder , aminos and phytos too

 

[Reef Jeff]

I have the same problem. My system drops both PO4 and NO3 to zero on its own even with a medium sized bio load and a heavy feeding schedule.

I dose a small amount of NaNO3 daily and a very small amount of KH2PO4 occasionally to maintain levels at 1-2 ppm NO3 and .05-.08 ppm PO4.

You can get KH2PO4 from Green Leaf Aquariums at http://greenleafaquariums.com/aquarium-fertilizer.html
And NaNO3 at Science Company at https://www.sciencecompany.com/Search.aspx?k=NaNO3.

This site has a nice dosing calculator: http://www.theplantedtank.co.uk/calculator.htm

 

[Randy Holmes-Farley Verified Community Expert]

It's actually become pretty common to dose either nitrate or phosphate or both.

i do not know if the claim will benefit, but it might.

Undetectable nutrients is also a big risk factor for dinos, and I personally would begin dosing. It is easy and you can stop any time.

 

[hatfielj]

My tank too has had trouble with barely detectable nitrates and undetectable phosphates. I have a heavy fish load and feed heavily several times a day. I just started dosing both nitrates and phosphates and so far the results are good. I've instantly noticed better polyp extension and colors. My tank consumes these nutrients daily because I add them, measure the new levels, then measure again before dosing more and the levels have dropped after 24 hours. I've also noticed my pH has been getting slightly higher during the day which to me means there is more photosynthetic activity and likely means that the previously low NO3 and PO4 levels were limiting growth.
I would recommend you give it a try. Just start slow and make sure to keep up with your measurements daily. I hope to get to a point where I can know exactly how much my tank consumes each day and automate it with a couple of dosing pumps.

 

[lbacha]

I started manually dosing kno3 & KH2PO4 a month ago and added it to my neptune dos a week ago. It has made a huge difference in my tank.

Prior to keeping my no3 and PO4 balanced I would have either 0 for both or if I fed more to try and boost nutrients I would have high PO4 and still no no3. My tank would get ugly brown algae all over it each time PO4 was high with no no3 (I'm not sure if this was Dino's or just diatoms). Once I started dosing my coralline and green algaes replaced all the brown algae. My cleanup crew keeps the small amount in check and the tank looks a lot better.

I would recommend dosing with pumps if you can as it is way easier than trying to overfeed or manually dose the correct amount

 

[Steve1500]

I have the same problem. My system drops both PO4 and NO3 to zero on its own even with a medium sized bio load and a heavy feeding schedule.

I dose a small amount of NaNO3 daily and a very small amount of KH2PO4 occasionally to maintain levels at 1-2 ppm NO3 and .05-.08 ppm PO4.

You can get KH2PO4 from Green Leaf Aquariums at http://greenleafaquariums.com/aquarium-fertilizer.html
And NaNO3 at Science Company at https://www.sciencecompany.com/Search.aspx?k=NaNO3.

This site has a nice dosing calculator: http://www.theplantedtank.co.uk/calculator.htm

I am also trying to raise my nitrates and phosphates in my 75G tank. To raise nitrates, the dosing calculator only has an option for potassium nitrate or ammonium nitrate. If I were to use sodium nitrate, do I use the potassium nitrate dropdown or will it skew my results? To raise nitrates, what is the difference between potassium nitrate and sodium nitrate?

 

[Randy Holmes-Farley Verified Community Expert]

I am also trying to raise my nitrates and phosphates in my 75G tank. To raise nitrates, the dosing calculator only has an option for potassium nitrate or ammonium nitrate. If I were to use sodium nitrate, do I use the potassium nitrate dropdown or will it skew my results? To raise nitrates, what is the difference between potassium nitrate and sodium nitrate?

Use the potassium nitrate entry. You'll never notice the difference, but to be perfect, use 16% less, so 0.84 grams sodium nitrate if it calls for 1 gram potassium nitrate.