Off the chart phosphates in tank with beautiful corals

[Magik]

Hi,

I just bought Hanna Ultra Low Phosphorus checker, testing my tank water was uneventful (39-40ppb, irrespective of GFO, feeding), so out of boredom I tested water from a very reputable LFS, from a big tank with many beautiful corals and some fish. The phosphates were of the charts! The checker showed maximum, but the water was very dark blue, almost black. Do you know how many ppm it is, if the water is that dark? The highest reading I had, 69ppb from "cooking" my old liverock, the water was still not a hint of a color.

And more important question: should I even bother checking phosphorus? I am starting a softie/LPS tank, have a bit of turf algae at the place where it grew on my live rock, no other problems. Strangely, removing GFO, or rinsing/not rinsing frozen food does not seem to impact my phosphates, same as feeding (from 3x day to every other day). Also my 1 day aged saltwater (Instant Ocean + RODI water) already tests 19-22 ppb, so looks like I had no chance anyway to get to the recommended (?) levels of 0.03 ppm...

 

[bertoni]

I am not sure whether checking the phosphate level is useful until diagnosing a problem. That said, 19-22 ppb for freshly-mixed saltwater seems a bit high. Maybe there's a measurement problem. You could check the water right after mixing. Maybe the container is leaching something. Do you have a freshwater phosphate kit?

 

[Magik]

No, I am using Hanna Ultra Low Range Phosphate meter. I was also surprised, so many people using Instant Ocean salt and I never heard complaints it is phosphate-rich. Maybe I am not doing the test properly? I tested a couple times, got values 19, 20, 22 and 9, but 9 was with checker lying horizontally by accident. My tank water consistently tests 39-40, except for one time I got 0, but that was when I was mixing very briefly, not 2 mins.

So you think that phosphates should not be monitored as a part of good practice?

 

[bertoni]

I'm not sure that testing the phosphate level regularly is useful unless there are signs of problems. One of the issues is the question reliability of hobbyist kits. Detecting something present at such low levels seems to be challenging in terms of technology. The effect of a higher phosphate level seems to vary from tank to tank, as well. If your tank is doing well enough, you might want to consider ignoring the phosphate numbers.

 

[bif24701]

No, I am using Hanna Ultra Low Range Phosphate meter. I was also surprised, so many people using Instant Ocean salt and I never heard complaints it is phosphate-rich. Maybe I am not doing the test properly? I tested a couple times, got values 19, 20, 22 and 9, but 9 was with checker lying horizontally by accident. My tank water consistently tests 39-40, except for one time I got 0, but that was when I was mixing very briefly, not 2 mins.



So you think that phosphates should not be monitored as a part of good practice?

Are you converting you Hanna numbers to PO4 numbers?


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[Lsufan]

In po4 your tank would be around 0.120 ppm but that's not really a surprise if your water change water is already at .06 or so. It seems like if u where using 0ppm water for water changes it would cut your po4 in half. Your tank would be around .06 ppm or somewhere in that range. U may want to try mixing some saltwater in a different container & test that. That may help u determine if it's your rodi or your container leaching po4.

 

[DivingTheWorld]

AFAIK, all salt mixes contain some phosphates. I always test my IO water change water mixed to 1.0264 with my Hanna Phosphorous tester. It generally tests between 0.01 and 0.04, but I did have one test hit 0.0705. I run GFO, so I'm not concerned about adding in this small amount as part of a water change.

 

[Magik]

Are you converting you Hanna numbers to PO4 numbers?


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Yes, in terms of phosphates ppm my tank is 0.12pm. Not bad, although my nitrates are 0, even if I used 5 times the reagents, in attempts to detect 0.5 ppm nitrate. I never ever got anything but 0ppm on this NO3 test (Red Sea), may try another one. I bought Phosphate meter when I had beginning of an algae outbreak, although snails took care of algae within couple weeks.

 

[Magik]

In po4 your tank would be around 0.120 ppm but that's not really a surprise if your water change water is already at .06 or so. It seems like if u where using 0ppm water for water changes it would cut your po4 in half. Your tank would be around .06 ppm or somewhere in that range. U may want to try mixing some saltwater in a different container & test that. That may help u determine if it's your rodi or your container leaching po4.

Yeah, I do not remember if I tested my RODI water for phosphates, although I do not think it is a problem, I have almost new RODI system and TDS is 0. The container is also also new and food grade, for feeding horses, should not be leaching anything. I was rinsing it between uses, but not very diligently, I also stored it for a couple days outdoor. Will see.

 

[Magik]

AFAIK, all salt mixes contain some phosphates. I always test my IO water change water mixed to 1.0264 with my Hanna Phosphorous tester. It generally tests between 0.01 and 0.04, but I did have one test hit 0.0705. I run GFO, so I'm not concerned about adding in this small amount as part of a water change.

Oh, that will be in line with what I am observing, with mine at 0.06pm. So far I cannot get any detectable nitrates, so went back to running GFO and I am also very slowly reducing amount of Marine Pure balls, with goal to get more desirable NO3O4 ratio. Dosing nitrates while running a ton of nitrate removing media (Marune Pure) would be silly, right? I monitor ammonia 24/7 with a digital probe, so I would know if I remove too many, although my tank is very lightly stocked, so I do not expect any problems.

 

[bif24701]

Phosphate RX will removed PO4 well, and cheato, high capacity GFO is a great choice (I mix it in with my carbon 1:2 GFO/carbon).

Dry foods can add a lot of PO4, try using more frozen/fresh/or live foods.

I highly suggest you get your NO3 to a detectable level at least. I have had nothing but problems with a NO3 <1ppm.

You said your corals are doing very well so they are getting the food and nitrogen they need clearly.

Can you tell me about your lighting and what kind of intensity/PAR/Duration you have?


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[Magik]

This video is another example - beautiful tank with 1-3 ppm (!) phosphates
https://www.youtube.com/watch?v=ZRIKW-9d2xI
but the tank has been running for 11 years, so I guess it is not a good model for newer tanks