Nitrates High, Phasphates low

[PNuke]

Hi all,
Long time follower, but not really into posting. I'm honestly just lost. I've had reef tanks for over 10 years with success but this was the first one I built from scratch with the intention to only grow out higher end Acros. Its a simple 40g breeder with 20L sump. Skimmer, filter floss, normal 5 chamber sump with macro. I keep ridiculous records and I am on day 856 with only rock, that is 100% covered in every color coralline you can think of, and only 5 fish, clean up crew and a cleaner shrimp and a 2in sand bed. No corals at all except a maxima clam that I rescued from my friends crashing tank. I wanted to wait until I got to a steady level with lower nitrates before I started my collection.

So my issue, and trust me, I have researched the heck out of this before coming here. Is that My nitrates are stuck between 22.3 - 22.8. My Phos bounces around between .000ppm and .024, and that's only because I have been dosing Reef Roids every other night. I just don't see how my 2.5yo 50lbs of rock could still be absorbing that much daily? I have the patience of a saint, so any suggestion short or long term are welcome.

All Hanna
Alk - 8.20
Cal - 430
Salinity - 1.026
Nitrates - Bounce around 22 - almost 23
Phosphates - Zero to .024 - Only because of dosing reef roids

Thanks in advance for any advice!

 

[PNuke]

To add to this. I tried microbater7 at the recommended nightly does with skim off then weekly with zero changes. Not doubting their product, just some more info.

 

[ThisIsTheWay]

Have you tried dosing phosphate or increasing Reef Roids? (Those are high in phosphate from what I remember)

I have a similar issue to you, in that my ratio of Nitrate to Phosphate is way off. I've got about 0.1 PO4 but 50-100+ NO3 and I think the expected nitrate ratio would be closer to 0.1 PO4 and 10-20 NO3.

From my understanding there are a couple things going on.

1. PO4 binds to rock. This means if you are trying to raise PO4 it will take a while to saturate the rock before you see a noticeable difference in the water. On the flip side, lowering PO4 will take time because as you lower PO4 in the water, the rock will release PO4 to stay in equilibrium with the water, thus raising the PO4 back up until enough PO4 has been removed from the rock that the overall equilibrium level in the tank drops.
2. NO3 is PO4 limited. This means that organisms need both NO3 and PO4 to function, if there is a deficit of PO4, the organisms in the tank cannot consume all the NO3 because of insufficient PO4. They will consume until PO4 is gone or almost gone, and any remaining NO3 will be left.

Based on the above info, I've personally been trying to feed more PO4 rich foods in my tank to try and bring my nutrient ratio back into balance. I've only just started recently so I admit I don't have any results yet but I have seen it work for other people.

For your tank, the super low PO4 readings seem to indicate that you've stripped your tank of PO4 completely and whenever you add Reef Roids it brings the PO4 up briefly but is then rapidly absorbed by the rocks in your tank, creating a PO4 deficit and leaving behind the NO3 that you see.

I will admit I'm still a bit of a newbie to reef tanks but I figured I'd throw this info out there since this is what I'm seeing based on my research and the info you've provided.

Best of luck and I'm curious what other's think since I'd like to solve this same problem in my tank too.

 

[PNuke]

Thanks for your reply. I have thought of dosing PO4, but wanted to try RR first. I need to read up on it. I've been doing this for many years now and I know the mantra, nothing good happens fast. But dang, 2.5 years now and still trying to get them down. I've read that higher nitrates as long as stable are ok with Acro's, and my mixed tanks do fine around 16 even with SPS. But I'm not about to try some of these pricier frags. I've been stuck at around 22 for 1.5 years now.

 

[ThisIsTheWay]

Stuck at 22 for 1.5 years is a long time. On the bright side it sounds like your system is super stable which is great.
That got me thinking though, how quickly do you plan to add corals and would you consider putting mid-range acros in to start?
The reason I ask, is because once you start adding corals to the tank they'll use up some of the nutrients themselves so maybe that would be enough to bring your nitrates down?

 

[PNuke]

I've thought about it. I fragged a rainbow acro off my main tank and it lasted about 2 months before it completely bleached. I got an an ICP test and everything tested fine but my nitrates. I've looked for bugs like a meth head and haven't seen anything.

 

[EeyoreIsMySpiritAnimal]

In what universe is 23 a high nitrate level? Especially IN A TANK WITH NO CORAL??

 

[Lasse]

Are you macros doing well? It seems that your tank is PO4 limited if you can trust the measurements. What do you use in order to measure PO4 and NO3? The backside with rising feeding when you are low in one nutrient and high in another is that both will rise. Dosing reef roids is a good "middle" way because they seem to have higher P/N quota than other foods. IMO - its an excellent food for maxima clams too.

I think that @ThisIsTheWay did a good summary of the state of knowledge (read - the most accepted acquired knowledge among hobbyists) for the moment.

If the RR does not rise your PO4 too at least 0.06 - 0,08 with time - I think that dosing PO4 will be a good choice. You have macros and macros have a high N/P quota in uptake. Many times 30:1 in N/P quota. It means that for every mg PO4 a macroalgae take up - it needs to take up around 19 - 20 mg NO3. If you start to dose PO4 - take it slowly - do not panic if it not rise in a week or two. Decide a dose based on a wanted concentration of around 0.06 PO4. If your concentration not rise - do not rise your dose to fast - let it stabilize before you rise your daily dose of PO4.

In your case with macro:s - is probably your macros that take up the PO4

Sincerely Lasse

 

[Randy Holmes-Farley]

I'd feed more, or dose phosphate.

 

[PNuke]

In what universe is 23 a high nitrate level? Especially IN A TANK WITH NO CORAL??

I'm aiming for between 5 and 10 stable for this tank. I know WWC keeps theirs around the 20's, but from my experience it hasn't worked out to well for me. But thanks for your very insightful post.
And I achieved this in my 220 before adding any coral over time.

 

[PNuke]

I'd feed more, or dose phosphate.

Thanks Randy. Been a long time reader of your articles and am most likely going to try food grade sodium phosphate.

 

[PNuke]

Are you macros doing well? It seems that your tank is PO4 limited if you can trust the measurements. What do you use in order to measure PO4 and NO3? The backside with rising feeding when you are low in one nutrient and high in another is that both will rise. Dosing reef roids is a good "middle" way because they seem to have higher P/N quota than other foods. IMO - its an excellent food for maxima clams too.

I think that @ThisIsTheWay did a good summary of the state of knowledge (read - the most accepted acquired knowledge among hobbyists) for the moment.

If the RR does not rise your PO4 too at least 0.06 - 0,08 with time - I think that dosing PO4 will be a good choice. You have macros and macros have a high N/P quota in uptake. Many times 30:1 in N/P quota. It means that for every mg PO4 a macroalgae take up - it needs to take up around 19 - 20 mg NO3. If you start to dose PO4 - take it slowly - do not panic if it not rise in a week or two. Decide a dose based on a wanted concentration of around 0.06 PO4. If your concentration not rise - do not rise your dose to fast - let it stabilize before you rise your daily dose of PO4.

In your case with macro:s - is probably your macros that take up the PO4

Sincerely Lasse

Thanks Lasse, appreciate the advice. I do not dose macros, only 10% water changes every 2 weeks. Going to go with sodium phosphate slowly and see if it levels out