Is the right phosphate-nitrate ratio important for corals ?

[Idech]

My question : should I dose phosphate alone (Neophos) ?

I’m having trouble keeping many corals and I am wondering if I should dose phosphate since my levels are low compared to nitrates. I’ve always read they should be 1:100. Could this be negatively affecting corals ?

Nitrates are 17.7 today and phosphate is between 0 and 0,03 according to the very imprecise Salifert test I have (it’s been 0,03 for a long time but since I have been dosing sodium silicate for dinos, my Hanna tester has been faulty so I can’t use it).

So to have a 1:100 ratio, my phosphates should be 0,177, let’s say 0,18. Should I increase it that much ? Not at all ?

Thanks

 

[Saltyreef]

As you dose phosphate, you may see nitrate reduce. Keep an eye on both.

Get yourself a hanna ULR phosphate tester or the red sea pro kit as its the best titrant test for color change and has a ULR procedure too.

Keep it up above .03 to give yourself wiggle room not to bottom out.

 

[Lost in the Sauce]

Start the Flame war here..


IMHO, there is No reason to be trying to hold PO4 between Zero and .03, ESPECIALLY when trying to battle dinos. You're Hanna checker is good what, +/- .05.. you are likely causing your own dino issues, holding there

The ratio is Far less important, than the stability of your dissolved nutrients.

Many very successful acro tanks and boutique aquaculture farms run phos up to .1 and have tremendous growth and color.

If you can't keep your po4 up, dosing will do it...

 

[jstndnhyr]

How are your other parameters like alk, calc, mag, temp, salinity, ph? If you're having trouble keeping corals alive, I'd make sure these parameters are in the correct ranges and stable before worring about nitrate and phosphate ratios.

 

[Idech]

Get yourself a hanna ULR phosphate tester or the red sea pro kit as its the best titrant test for color change and has a ULR procedure too.

I do have a Hanna ULR phosphate checker. As I mentioned, it becomes useless when you have high silicate levels. I’ll look at Red Sea.

Start the Flame war here..

Hum, it’s wasn’t done intentionally. I’m not experienced enough yet to know what starts wars !

IMHO, there is No reason to be trying to hold PO4 between Zero and .03, ESPECIALLY when trying to battle dinos. You're Hanna checker is good what, +/- .05.. you are likely causing your own dino issues, holding there

I am really not trying to hold PO4 low. This is just how it is. Before my nitrates were always dropping near 0 and I dosed both nitrates and phosphate to keep a certain ratio. The tank is 20 months old now and for the past 4-5 months, nitrates have been increasing without having to dose.

If you can't keep your po4 up, dosing will do it...

I am willing to do that. What level should I aim for ?

 

[Idech]

How are your other parameters like alk, calc, mag, temp, salinity, ph? If you're having trouble keeping corals alive, I'd make sure these parameters are in the correct ranges and stable before worring about nitrate and phosphate ratios.

Alk : 9.5
cal : 460
mag : 1600 (a little too high, caused by error on my part)
Temp : 78
Salinity : 1.026
PH : 8.1

Here are some of the corals I can keep : GSP, pulsing xenia, mushrooms, Acan, Duncan, 3 hammers but not much growth.

Some of the ones I can’t keep so far : torches, hammers, easy SPS, goniopora, frogspawn

 

[Lost in the Sauce]

Hum, it’s wasn’t done intentionally. I’m not experienced enough yet to know what starts wars !

"The right numbers" in reefing gets a lot of panties in I wad. Nothing that you've said. My response is likely to open up that can of worms.

I am really not trying to hold PO4 low. This is just how it is. Before my nitrates were always dropping near 0 and I dosed both nitrates and phosphate to keep a certain ratio. The tank is 20 months old now and for the past 4-5 months, nitrates have been increasing without having to dose.

What size is the tank? What are your export methods ie skimmer, macro? Can you Feed enough to raise them? That's usually the Best option.. fat fish Stay healthier and pass the nutrients into the water.

I am willing to do that. What level should I aim for ?

See above. This changes reef to reef but there is nothing wrong with looking for 15 nitrates and .1 phosphates.

 

[Nano sapiens]

I think you'll find that for a younger system like yours 0.05 - 0.1 PO4 is fine.

Keeping NO3 somewhere in the 5 - 10 ppm range is fine IMO/IME. It's important that some NO3 be present, but we collectively have seen that the range for each particular successful system can be as wide as 1 ppm to 40 ppm (some even higher). The 1:100 PO4/NO3 ratio can be used as a rough guide when PO4 is as mentioned above, but certainly isn't a set-in-stone kind of thing.

The main thing is to take any alterations you do very slowly as the system/organisms need time to adjust to the changes.

 

[Idech]

What size is the tank? What are your export methods ie skimmer, macro? Can you Feed enough to raise them? That's usually the Best option.. fat fish Stay healthier and pass the nutrients into the water.

Tank is 75 gallons, no sump. Export methods are an internal skimmer running 12 hours a day and filter floss in a filter that I change every 5-7 days.

I feed three times a day : frozen morning and night and flakes at noon (spirulina flakes, for the tang that won’t eat nori). Since my nitrates are 17.7 ppm, I was thinking about reducing feeding. Fish are fat, I think.

 

[Garf]

I’ve deliberately messed with my ratio of phos to nitrate, absolutely no change in coral behavior. Caveat, my levels are high, so have probably breached the normal reef keeper limits. Phos has gone from 1.4ppm to 0.3 whilst maintaining 40ppm nitrate, now that’s a ratio wobble.

 

[Idech]

I’ve deliberately messed with my ratio of phos to nitrate, absolutely no change in coral behavior. Caveat, my levels are high, so have probably breached the normal reef keeper limits. Phos has gone from 1.4ppm to 0.3 whilst maintaining 40ppm nitrate, now that’s a ratio wobble.

That’s interesting !

 

[Garf]

That’s interesting !

I messed with nutrient levels 10 years ago by maximizing an algae scrubber, same result with another caveat, it was a softy tank, apart from an indistructable acro, dunno maybe a digi, lol. Trying to get a prize for longest sentence posted today, lol.

 

[Uncle99]

Yup, dose the Neophos like you suggested, 0.03ppm is on the traditional lower side, but if testing is slightly out, it may actually be zero, and that would be a bad level for everyone in your tank.
Don’t get caught up in the number games, get that very very nice system to a point “it likes to run stable at and hold it there.
.1-.15ppm phosphate and 17.7ppm nitrate is just fine in your mixed.
Bump the phosphate only until you can get .1ppm and continue to Maintain that level.
We don’t want to see consistent increases or decreases in these two, we want the to hold steady including the water changes feeding times, keep these steady.

 

[Randy Holmes-Farley Verified Community Expert]

My question : should I dose phosphate alone (Neophos) ?

I’m having trouble keeping many corals and I am wondering if I should dose phosphate since my levels are low compared to nitrates. I’ve always read they should be 1:100. Could this be negatively affecting corals ?

Nitrates are 17.7 today and phosphate is between 0 and 0,03 according to the very imprecise Salifert test I have (it’s been 0,03 for a long time but since I have been dosing sodium silicate for dinos, my Hanna tester has been faulty so I can’t use it).

So to have a 1:100 ratio, my phosphates should be 0,177, let’s say 0,18. Should I increase it that much ? Not at all ?

Thanks

There's no reason, IMO, to ever use ratios in setting target levels. I can go on and on about the rationale, but in short, I recommend always looking at absolute levels regardless of where the other of the N and P pair might be.

I recommend phosphate to be about 0.02 to 0.1 ppm, with higher than that range better than below it. Your phosphate may be lower and I'd caution about that, and possibly dose phosphate.

I recommend 2-10 ppm nitrate, with higher than that range better than below it. You may be fine at 18 ppm.