Dosing Phosphates, but not nitrates?

[Deephouse_jedi]

Hey everyone,

I have a 45 gallon mixed reef. Softie and LPS dominant with a couple SPS. I have a good handle on my nitrates. They are stable around 5-10ppm. My Phosphates always read 0. I have dosed a small amount of PO4 before and was able to increase it to .03-.06. That only lasts about a day before my tank uses it all and it's back to 0. Should I continue to dose PO4 in these small amounts everyday? Does anyone know why my tank would be using so much PO4, but not Nitrates? Everything in my tank looks good and I'm happy. I'm just worried of my PO4 bottoming out. I do know even though my test kits read 0 there are still probably some PO4 in the tank.

 

[Quietman]

Can I ask you what the nutrient removal method you're using is? Carbon dosing, skimmer only, refugium?

Not sure low phosphates with a low stable of nitrates is a huge concern though.

 

[LC8Sumi]

PO4 is probably being sucked up by the rocks (unless you have algae). One day the sponge will fill & the levels of po4 will skyrocket.

 

[Deephouse_jedi]

Can I ask you what the nutrient removal method you're using is? Carbon dosing, skimmer only, refugium?

Not sure low phosphates with a low stable of nitrates is a huge concern though.

I have the JBJ 45 all in one, so no refugium. I was dosing vinegar for a few months. I was having trouble with my nitrates when the tank was new and this helped. I have since stopped since the tank is now able to control the nitrates itself. I do a 10% WC every week, thinking of changing it to 20% every other. Yes I have a skimmer, medium a dry/wet skim. I empty it about every 7-10 days.

 

[link81]

I had to dose po4 for a while also. now i run with 0 or barely detectable po4 and zero nitrates.
I only have my fuge lit for 5 hours a night. much more and nutrients bottom out and i get dino.

reason i was dosing is that i had detectable nitrates with no phosphates, so my chaeto wasn't uptaking anything. now i'm not dosing either no3 or po4.

 

[Deephouse_jedi]

PO4 is probably being sucked up by the rocks (unless you have algae). One day the sponge will fill & the levels of po4 will skyrocket.

Ok interesting, I haven't heard of this before. The tank is still fairly new at about 8 months or so this is a possibility.
I did forget to mention I have no algae. So that does rule out algae taking all the nutrients.

 

[link81]

I think the rock mostly acts as a buffer, not a sponge per-se.

i'll let someone smarter then me explain it.

Phosphates are zeroing out every day, a few specific questions

Thanks for compounding the thread for us! First i would turn your skimmer back on. They remove alot of dos which is why your water is browning, and they dont remove much for po. I would also put gac back in that will help with the water clarity and again wont bother po. Do u have a tank shot so...

www.reef2reef.com

 

[Smarkow]

Ok interesting, I haven't heard of this before. The tank is still fairly new at about 8 months or so this is a possibility.
I did forget to mention I have no algae. So that does rule out algae taking all the nutrients.

I’ve kind of wondered along these lines myself. I have low P (around 0.015 hanna ULR) and undetectable nitrate with a 75 gallon fuge..

I would much rather have some detectable nitrate than phos, a few of my corals do struggle with light colors.

Maybe OP and I represent two extremes?

 

[LC8Sumi]

I think the rock mostly acts as a buffer, not a sponge per-se.

i'll let someone smarter then me explain it.

Phosphates are zeroing out every day, a few specific questions

Thanks for compounding the thread for us! First i would turn your skimmer back on. They remove alot of dos which is why your water is browning, and they dont remove much for po. I would also put gac back in that will help with the water clarity and again wont bother po. Do u have a tank shot so...

www.reef2reef.com

A sponge is a buffer, isn't it?

 

[Quietman]

So...great! I would think you're fine. If the low phosphates are a concern (and as I said, I'm not sure they are if you have nitrates - I'll let others comment) then dose. I wouldn't. Now if I had phosphates and no nitrates (which I've had) different story and I fed more and cut back on NoPoX.

I'd be worried that if you start chasing numbers...then you're going to cause instability into an obviously stable system.

 

[link81]

A sponge is a buffer, isn't it?

the way i understood it is that the rock will absorb po4 up to the concentration that the water is, but not more. then when the water is lower concentration it will release it to maintain it.

what rock will not do, is absorb phosphate until it is "full" then stop. (unless po4 concentrations are maintained super high for a long period of time)

so:
if you keep your po4 at 1ppm, the rock will absorb until it is also 1ppm, then when your po4 drops to .5ppm the rock will release it until it is balanced back out.


** this is how in understand it, i'm far from an expert on this**

@Randy Holmes-Farley @Lasse

 

[justd1]

Following along. I've got the same thing going on for the past month in my 75g. It's been running for 2 years now. Been dosing NeoPhos daily to raise PO4 to .03ppm. The next day it's at zero again(Hanna checker, fresh reagent). Nitrates are steady at 10. Monti's, Lepto's, and favia's losing color and flesh, as well as my space invader pectinia's skeleton poking thru. My Acro's look good(not growing but look good). Alk is at 8.0. Skimmer and ATS offline. No water changes. It's frustrating and I'm also looking for answers.

 

[link81]

@justd1 i think the consensus in the thread i posted above was to dose more. (or feed more)
something is consuming them.

I made my own po4 solution, i can dig out the calculations if you want. it was far cheaper then buying an off the shelf product.

 

[Ling_Thing]

I’ve been through this and I feel like a majority of tanks run into This problem. I have to dose 250ml of neophos into my 5 gallon ato container to maintain detectable p04 and I also dose 15ml of me coral n03 everyday in my reefer 450. Jack Kent gave me a 2 gallon jug of neophos and as soon as I’m done with it I’m going back to my trisodium phosphate mixture. My tank is also packed with acros which are sponges for nutrients. There are far more advantages to having high nutrients than low imo. I shoot for 10ppm n03 and .06 p04. If I stop dosing either nutrient I can see my acros aren’t happy and start to lose color. Keep in mind I don’t have a refugium, no algae scrubber, no Carbon dosing, no gfo or GAC, and I only run my skimmer for an hour every 3 days (cone s 2). The more sps you have the more nutrients they need. Hope this helps. Thanks Garrett

 

[Deephouse_jedi]

So...great! I would think you're fine. If the low phosphates are a concern (and as I said, I'm not sure they are if you have nitrates - I'll let others comment) then dose. I wouldn't. Now if I had phosphates and no nitrates (which I've had) different story and I fed more and cut back on NoPoX.

I'd be worried that if you start chasing numbers...then you're going to cause instability into an obviously stable system.

This was exactly what I was thinking. Everything looks good and I'm happy with the colors. So why mess with it, right? Y only concerns would be dino. So first sign of it maybe start dosing then is what I might do.

 

[LC8Sumi]

the way i understood it is that the rock will absorb po4 up to the concentration that the water is, but not more. then when the water is lower concentration it will release it to maintain it.

what rock will not do, is absorb phosphate until it is "full" then stop. (unless po4 concentrations are maintained super high for a long period of time)

so:
if you keep your po4 at 1ppm, the rock will absorb until it is also 1ppm, then when your po4 drops to .5ppm the rock will release it until it is balanced back out.


** this is how in understand it, i'm far from an expert on this**

@Randy Holmes-Farley @Lasse

Makes perfect sense! Thank you!

 

[justd1]

@justd1
I made my own po4 solution, i can dig out the calculations if you want. it was far cheaper then buying an off the shelf product.

Yes, I may need that. Buying NeoPhos for an extended period of time will get spendy.
Thank you!

 

[Marlon C]

PO4 is probably being sucked up by the rocks (unless you have algae). One day the sponge will fill & the levels of po4 will skyrocket.

I doubt this is the case. In my tank I'm dosing .5ML of a phosphate I make and it raises it daily to .03 then drops to zero the next day. But I know it's not the rocks consuming po4. It's the corals and the cheato. P04 is food for the corals not for the rocks. I dose. Nitrate because it does drop also down to 2.5 which to me is rather low. So I dose about 10ml each ml raises it .1. But like I said I make my own concentrations. If your interested in a cheaper way to dose then buying offshelf stuff let me know.

 

[link81]

@justd1
here is the thread i pulled my inital calc from.
it'll point you in the right direction. shoot me a msg if you have any questions.

Po4 Dosing

looking into dosing phosphates to bring them up to a detectable level. I have a spare 1.1 dosing pump that i'll be using. Plan on mixing up my own solution. is there a reason to use MSP DSP or TSP over one another? are there any calculators i can use to get a starting point? i.e max solubility...

www.reef2reef.com

 

[brainandersen752]

How You made your po4 solution? Could You share with me?