Dosing Nitrates and Phosphates

GregOyeah · Mar 13, 2018

Ive had undetectable nitrates and phosphates forever and several of my corals have more pale pastel type colors than the rich deep colors that they should.

I want to dose nitrate and phosphate to help remedy this. So Im gonna dose a potassium nitrate solution to slowly raise my nitrates to around 3-5ppm. Im also gonna dose monopotassium nitrate to raise my phosphates to .04ppm. (Im open to suggestion on what a better ratio would be)

Ive read that there is a balance between dosing phosphates and nitrates. Dosing just phosphate can make your nitrate bottom out and vice versa. So my question is, is there a particular regimen or way to do this so Im not canceling one dose out with the other? if that makes sense? or am I overcomplicating this?

I just dont want to start doing this and after a couple weeks realizing Ive just been chasing my tail .

ihavecrabs · Mar 13, 2018

#Mods can we get this moved over to the Randy's Reef Chemistry forum for some better responses?

#reefsquad for the PO4 dosing (as I have never had an issue with mine being too low.. mine is usually too high ;Wacky

As far as dosing Potassium Nitrate for your nitrates, here is a good reference:

Randy Holmes-Farley said:
Here's my standard recipe for potassium nitrate, and it can be adjusted easily up or down in concentration, as needed:

Dissolve 10 grams potassium nitrate in 1 liter of fresh water. That 10 grams contains 6.14 grams of nitrate, so that solution is 6,140 ppm nitrate.

If you add 1 ml of the solution per 2 gallons of tank water volume, that will boost nitrate by 0.8 ppm nitrate.

As a rough estimate, 10 dry mL of powder weighs about 10 g.

As far as the ratio you are referring, I have always kept mine in the following ranges:

NO3 2-5ppm SPS or 5-10ppm Softy/LPS (This is general guidance.. there are many people shooting higher and lower for all types of corals.)
PO4 .02-.05 SPS .02-.08 for Softy/LPS (Again, general guidance)

dbl · Mar 13, 2018

Happy to move it over. Couple of questions though?

What are you doing for nutrient export/control presently? Fuge with algaes, running GFO, water change frequency, skimmer, etc? May be possible to increase nutrients by decreasing export activities.

You can also increase your nutrients by feeding more. May be worth a shot instead of trying to "dose" something. Increase feeding slowly over a week or two and see what, if anything, happens.

saltyhog · Mar 13, 2018

Seachem makes a product called Flourish that is an easy way to dose phosphate. It's designed for freshwater planted tanks but works great for dosing a reef tank. I'm currently using it.

This is a great source of lab grade sodium nitrate. Very inexpensive and this bag will last a long, long time.
https://www.amazon.com/gp/product/B0190TOJUS/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

GregOyeah · Mar 13, 2018

I have a chaeto fuge, a gfo/carbon duel reactor and do a 5% water change a week. Ive tried feeding more and it didn’t do anything. Same with taking equipment offline for the most part. I also just don’t want to overstock my tank with fish for the sake nutrients

GregOyeah · Mar 13, 2018

saltyhog said:
Seachem makes a product called Flourish that is an easy way to dose phosphate. It's designed for freshwater planted tanks but works great for dosing a reef tank. I'm currently using it.

This is a great source of lab grade sodium nitrate. Very inexpensive and this bag will last a long, long time.
https://www.amazon.com/gp/product/B0190TOJUS/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

I already have potassium nitrate and mono potassium nitrate.

What I was concerned about was if there is a specific dosing regimen or anything to follow for this bc I had read dosing nitrates can bottom out your po4 and vice versa so I just don’t want to be potentially canceling out my doses.... if that’s even possible.

I’ve just read there’s a balance between dosing the two and I want to get a head start to finding it

saltyhog · Mar 13, 2018

Do you mean potassium phosphate instead of potassium nitrate? Why are you running GFO if you're trying to raise PO4?

GregOyeah · Mar 13, 2018

Whoops sorry yes I have potassium nitrate and monopoasstium phosphate.

I haven’t started dosing phosphate yet, when I do, the gfo will come offline. I was previously dosing nitrates but not phosphates but have decided it would be better to dose both bc of the effect one can have on the other. Which is why I have the questions that I have about dosing both

Dogtown · Mar 13, 2018

If you are trying to raise PO4, start by discontinuing the GFO regimen. That’s should be your first step in your effort to bring up your PO4 gradually. Dosing PO4 is something you would phase in later and only if actually needed. You will be glad.

Whipples · Mar 13, 2018

You may be, due to an extended period of time, be in a position where your dosing is getting used up much quicker as the system is taking it up after being without it for so long! As for quality products that you can mix and make to your preference (in terms of how much of a PPM boost per milliliter) check out Green Leaf Aquariums for dry "fertilizers" (planted tank term

). They sell food grade potassium nitrate and monopotassium sulphate inexpensively and come in slick containers. There are several calculators you can use to determine how many grams to add to RODI water for your desired levels

http://greenleafaquariums.com/aquarium-fertilizer.html

http://www.theplantedtank.co.uk/calculator.htm

ihavecrabs · Mar 13, 2018

GregOyeah said:
Whoops sorry yes I have potassium nitrate and monopoasstium phosphate.

I haven’t started dosing phosphate yet, when I do, the gfo will come offline. I was previously dosing nitrates but not phosphates but have decided it would be better to dose both bc of the effect one can have on the other. Which is why I have the questions that I have about dosing both

I like where @dbl is going here.

Might be worth to stop GFO and carbon as these are likely stripping your water. Even the algae is contributing to the low numbers. Might be worth seeing how the no3 and po4 look before removing or reducing the algae though.

saltyhog said:
Do you mean potassium phosphate instead of potassium nitrate? Why are you running GFO if you're trying to raise PO4?

Nice catch

dbl said:
Happy to move it over. Couple of questions though?

What are you doing for nutrient export/control presently? Fuge with algaes, running GFO, water change frequency, skimmer, etc? May be possible to increase nutrients by decreasing export activities.

You can also increase your nutrients by feeding more. May be worth a shot instead of trying to "dose" something. Increase feeding slowly over a week or two and see what, if anything, happens.

Good call!

Lasse · Mar 14, 2018

IMO - stop the GFO and start to dose N. My experiences in this type of set ups is that they normally ending up in N starvation. This because N has an ability to leave the system (the aquaria) through the air because two of the N species (N2 gas and NH3) is volatile - none of the P species is known to be that (in normal pH). I prefer to use NO3 as N source but I know that there are persons out there that use other N species (as urea)

I have a similar set up as you and I add around 1 - 2 ppm on a daily basis - my NO3 level vary between 0.25 - 5 ppm - if I reach 5 ppm - I stop (or slower) the dosage for a while. I have stop GFO for the moment - but if the PO4 level arise - I put it in again. If you use a reactor - IMO - its important to take out the whole reactor and before you put it in again - rinse the media with a little tap water. I use AL99 media from Triton - its not a GFO but have the same function but based on Al instead of Fe

Sincerely Lasse

Randy Holmes-Farley · Mar 14, 2018

GregOyeah said:
I already have potassium nitrate and mono potassium nitrate.

What I was concerned about was if there is a specific dosing regimen or anything to follow for this bc I had read dosing nitrates can bottom out your po4 and vice versa so I just don’t want to be potentially canceling out my doses.... if that’s even possible.

I’ve just read there’s a balance between dosing the two and I want to get a head start to finding it

No, there's no specific regimen that is needed. They do not cancel each other out.

It certainly is true that if one is super low and is limiting the growth of organisms (algae, corals, etc.) then if you add that one, demand for both N and P may rise, potentially lowering the other. That can be good or bad, but if you are actually dosing and monitoring both, there's no substantial worry.

I think a few ppm nitrate and 0.02-0.03 ppm phosphate is a fine target range for most reef tanks.

In your case, I'd stop the GFO and start the nitrate, and possible also start the phosphate with an eye to stopping if it it rises more than you want.

dsh92056 · Mar 14, 2018

Stop the GFO. Wait two weeks. Retest and see if your parameters are moving in the direction you want them to go. If there up test again in a week and see if it went up more or stayed the same. Then consider dosing or not dosing. It takes weeks for things to change. Why would someone stop GFO and immediately start dosing without knowing if just stopping the GFO will fix the problem.

Reefing is a marathon not a Sprint

Randy Holmes-Farley · Mar 15, 2018

dsh92056 said:
Why would someone stop GFO and immediately start dosing without knowing if just stopping the GFO will fix the problem.

Reefing is a marathon not a Sprint

You sprint when a tiger is chasing you.

The reason here: Because too low of phosphate is more of a problem than too high, and too low gives an immediate risk of dinos and/or corals starving.

hatfielj · Mar 20, 2018

So it sounds like I may need to start dosing phosphate too since mine is now reading zero after I started dosing nitrates.

Aquamaniak · Mar 21, 2018

I'm dosing 2ppm of nitrates daily, that's barely enough to keep it at around 1-3 ppm nitrates. Phosphates are very low too, I have to add it too, even though I have lots of hair / cotton algae and cyano. This hobby is quite frustrating sometimes :/

Scrubber_steve · Mar 21, 2018

Stop the gfo as others have said & shorten the photo- period to 9 hours / day for chaeto before considering dosing

vio · Mar 21, 2018

Remove the Macro Algae ( Chaetto) they may strip all NO3, cut 70% from GFO , let the tank to balance for few weeks , then see if you have to correct some, NO3 2-4 ppm and PO4 0.02 to 0.05 , works great for me 99% SPS in 300 Gal. tank.

Randy Holmes-Farley · Mar 22, 2018

Aquamaniak said:
I'm dosing 2ppm of nitrates daily, that's barely enough to keep it at around 1-3 ppm nitrates. Phosphates are very low too, I have to add it too, even though I have lots of hair / cotton algae and cyano. This hobby is quite frustrating sometimes :/

In general, the algae growth is one main reason why we used to recommend lower nitrate and phosphate than seems the trend today, with added other foods to help make up for the deficit in corals (e.g., amino acids, target feeding of corals, etc.).