Just how much nitrate is okay? What about Phosphate?

[Evan West]

If phosphates become an issue do you think that running GFO is a good solution to reducing them or would you recommend another method?

 

[Sabellafella]

If phosphates become an issue do you think that running GFO is a good solution to reducing them or would you recommend another method?

Depends. If your p04 its very very high, use somthing like lanthinum chloride to bring it down slowly. Gfo has the potential to be dangerous but its a good method to follow if you indeed have small rising p04 problems. Btw i keep my nitrate between 5 and 25, w.e floats my boat at the time

 

[mcarroll]

I may not be thinking of the same thing you are, but I suspect you got that backwards:

Latham chloride is potentially dangerous, toxic if ingested or in your eyes, etc. (see MSDS)

Here's a long piece on its use:
http://www.coralmagazine-us.com/content/foiling-phosphate\

Dude killed some of his critters with it...long article, look for text in red...​

GFO on the other had is easier to use and is known to be safe under almost all circumstances....it can have a lowering effect on alkalinity.

As with all things it's still a good idea to use GFO in moderation, with small quantities in use being changed frequently...rather than the other way around.​

 

[saltyfilmfolks]

Reread Randy's article on Po. He does cover a couple of them. And yes is did have to Reread them as well as they are quite in depth. In fact I still reread them as I progress in the hobby.
A refugium is another way to control excess phosphate. Also nitrates.
Personally I prefer the refugium. Phosphates and nitrates are nutrients so the plants in the fuge use up these nutrients as fertilizer (like your corals do). When the plants get too big you trim them. "Exporting" them.

Using chemical means for excess nutrient export you do have to pay a little closer attention to not strip the water Colum of those nutrients as it will starve the corals.

Something we see here quite often is the use of chemical nutrient removal as well as mechanical when there is no excess. Overskiming and stripping are terms you'll hear quite often to describe this.

The goal is to find a balance between the nutrients you put in as food and to only pull out the excess.
IMO using macro algaes as nutrient export is an easier way to balance a system as if there's lees food the plants grow less. With chemical means it's more similar to medicinal dosing as you need to know the amount of exess and then correctly Gage the amount of chemical to use to remove the exess without over stripping.

 

[sghera64]

If phosphates become an issue do you think that running GFO is a good solution to reducing them or would you recommend another method?

My NO3 is <1ppm (Nyos kit) and my phosphates are <0.009ppm (<9ppb, Hanna ULR Checker). I got there with very limited feeding, carbon dosing and probably over skimming. It took a while before I saw my LPS and SPS shriveling up or dulling in color with very little growth. Also, I elevated my HCO3- levels to 200 ppm CaCO3. Essentially, I had an Ultra Low Nutrient system with higher HCO3-. I don't recommend it.

I'm now trying to get my NO3- and PO4--- higher. I'm feeding a lot more, using amino acids and reef chilli. I only skim at night now and I've totally stopped carbon dosing (vinegar). But, the two levels have not moved up. However, with all that feeding, the fish are fatter, coral color has returned and my LPS's have puffier polyps. Even my goniopora stokes are coming back to life.

Bottom line: be careful about going too far into the ULNS range. Hobbiest meters can't tell you how close you are to zero. I guess they are only good at indicating how far, in grosser differences, we are above zero.

 

[bubbaque]

My NO3 is <1ppm (Nyos kit) and my phosphates are <0.009ppm (<9ppb, Hanna ULR Checker). I got there with very limited feeding, carbon dosing and probably over skimming. It took a while before I saw my LPS and SPS shriveling up or dulling in color with very little growth. Also, I elevated my HCO3- levels to 200 ppm CaCO3. Essentially, I had an Ultra Low Nutrient system with higher HCO3-. I don't recommend it.

I'm now trying to get my NO3- and PO4--- higher. I'm feeding a lot more, using amino acids and reef chilli. I only skim at night now and I've totally stopped carbon dosing (vinegar). But, the two levels have not moved up. However, with all that feeding, the fish are fatter, coral color has returned and my LPS's have puffier polyps. Even my goniopora stokes are coming back to life.

Bottom line: be careful about going too far into the ULNS range. Hobbiest meters can't tell you how close you are to zero. I guess they are only good at indicating how far, in grosser differences, we are above zero.

Just a heads up for when u start raising your phosphate, that if your Hanna checker is reading 9ppb it comes out to .o28ppm.

 

[sghera64]

Just a heads up for when u start raising your phosphate, that if your Hanna checker is reading 9ppb it comes out to .o28ppm.

Why is that?

Is it because the ULR is reporting phosphate as Pi-P and not PO4---?

 

[sghera64]

Just a heads up for when u start raising your phosphate, that if your Hanna checker is reading 9ppb it comes out to .o28ppm.

I think I got it. M.w. Of P is 31. M.W of PO4 is 95, or 3.06 times larger. If my Hanna ULR reads 9ppb-P that equates to 3.06 times that as PO4---, or 27.6 ppb-PO4 (0.028 ppm-PO4)

 

[sghera64]

Just a heads up for when u start raising your phosphate, that if your Hanna checker is reading 9ppb it comes out to .o28ppm.

Bubbaque, do you use the Hanna ULR?

 

[bubbaque]

I use the Hanna phosphorus checker, which is the one that gives results in ppb. I use this chart when testing to convert.

 

[Bunkinator]

try for zero on both, skimmer, fuge, GFO , and feed feed feed your fish and corals heavily... that will make for fat healthy fish and corals and a clean sand bed and less scraping of the glass.. many corals depend more on light and alk than they do on food in the water column.

 

[sghera64]

I use the Hanna phosphorus checker, which is the one that gives results in ppb. I use this chart when testing to convert.

Okay, I have a question for you (or anyone out there) about the Hanna ULR (ppb-Pi) Checker [HI 736].

When I follow the assay method in the kit, I consistently (I use a timer) shake to dissolve the powdered reagent in the sample tube for 2.5 minutes. Then I insert it into the checker and press the button to start the 3:00 countdown timer. My readings generally come out to be 005 to 009 (ppb-Pi). Now, if I re-zero the instrument with the other cuvette and immediately repeat the measurement (click the front button and do not hold it to start the 3:00 timer), I almost always get a reading of 000 ppb-Pi. If I get a higher reading, say 001 or 003, then it does not matter how many times I repeat the zero-calibration and remeasurement, I get just about that same reading each time.

I even made up a phosphate standard using TSP (hardware store). That gave me a reading of 24 ppb after the 3:00 timer, but 16, 16, 17, 17, 17, 16, 13, 15, 14-ppb upon rezeroing and immediately remeasuring (20 second intervals).

Have you seen this time-based effect?

I'm inclined to believe that micro bubbles are still present and obscuring the reading after the 3:00 wait period. They dissipate and the reading is stable after that for another 5 minutes.

Does anyone know if the method and instrument are so time sensitive that a valid reading can only be obtained after the 2:00 minute shake plus 3:00 wait times?

I'm asking because, in my case, it makes the difference in my conclusion. If the 3:00 reading is the right one, then I have about 0.028ppm-PO4. If the stable one obtained after about 3:30 minutes is the correct one, then I have non-detect levels (e.g. <0.03ppm-PO4).

 

[bubbaque]

I always get different answers with the hanna phosphorus no matter how perfect I try to do the test.

 

[jason2459]

I describe my method to use the hanna ulr phosphorus checker in my thread here comparing multiple po4 test kits. I get pretty consistant and reliable results for me.

https://www.reef2reef.com/threads/p...s-pro-salifert-hanna-checkers-seachem.222628/

 

[sghera64]

I describe my method to use the hanna ulr phosphorus checker in my thread here comparing multiple po4 test kits. I get pretty consistant and reliable results for me.

https://www.reef2reef.com/threads/p...s-pro-salifert-hanna-checkers-seachem.222628/

Thank you for the reference to your work. I read it and understand it.

I did the experiment to verify (and cross-check) that you can calibrate the instrument with one cuvette of sample water and then read (no reagent) another blank sample with a different cuvette to get a zero reading. I then reversed the order of the cuvettes (calibrate with #2 and read #1) because the instrument will not give negative readings. And again, I get a zero reading. All this is to say that we can run the assay as described [calibrate, add reagent, mix for 2:00, stand for 3:00 then read] followed by a re-calibrate and re-read using the second cuvette to calibrate and the original reacted sample which has now been standing for 3:20+ minutes without having to worry about bias from using a second cuvette to calibrate.

So, I'm curious if you ever re-read a given sample (or allowed a 3:20+ minute standing period) to see if you get a near duplicate reading.

Either way, your work does indicate to me that in the 100 ppb-Pi range (0.300ppm-PO4), it is accurate against the Hanna standard. I'm wondering if you've done a 10:1 dilution with RO/DI water on that standard and got a ~10ppb-Pi reading.

 

[jason2459]

I have not diluted and tested yet. My curiosity didn't take me there yet. My testing and comparisons with Triton has shown it to be in line with their results over many samples sent in and tells me I'm satisfied with the precision and accuracy of the ulr checker and how I perform the tests.

Here's another thread that also links to all the other threads I've done comparing many different test kits over time and all also included at least a po4 test with the hanna ulr and compared against Triton's results
http://reef2reef.com/threads/big-3-...os-elos-salifert-api-hanna-triton-awt.234660/

 

[orbitee2015]

My Nitrates are 20ppm as of today. A few months ago it was 40. No issues its been like this for 3 months. Phosphates are 0. My sps's never looked so good.

Is that a 8 bulb ati light fixture?

 

[mcarroll]

many corals depend more on light and alk than they do on food in the water column.

I'm not sure that's very true since it's more complicated than that and depends on local conditions of the coral.

Do you have a particular class of corals you're talking about? Or a particular food item you're thinking of?

In general, it seems that corals need water flow, nutrients and not-too-much light in a very interrelated way - no simple preferences one way or another. Nutrients aren't limited to food, per se, either....nitrates, ammonium and lots of other organic compounds in the water column are nutrients to many or most corals.

All this is to say that we can run the assay as described followed by a re-calibrate and re-read using the second cuvette[...]without having to worry about bias from using a second cuvette to calibrate.

No, not without worry.

If the cuvettes aren't pretty well identical, they will give different results. Even a stray fingerprint can cause issues. And the cuvettes scratch fairly easy.

So if you have a pair of shiny new cuvettes, it will work....I've done it too.

But that's not how it was intended to be run so there are definitely issues to be aware of.

 

[reeftankdude]

My Nitrates are 20ppm as of today. A few months ago it was 40. No issues its been like this for 3 months. Phosphates are 0. My sps's never looked so good.

How do you prevent nuisance algae growth with such high nitrate levels? thanks