From high phosphates and low nitrates, to low phosphates and high nitrates

[CatWhispurrer]

Hello,

I use a bio-pellet reactor. A few weeks ago my phosphates were high (0.16ppm Hanna) and my nitrates were undetectable (Salifert). I realized the high phosphates were being caused by my RO/DI that needed cartridge changing (which has been done).

So I added some Rowa GFO in a Phosban reactor and brought the phosphates to 0. Now I've noticed the nitrates are 10ppm. One of my feather dusters died, along with a snail, and my sand sifting star is missing. My sea urchin is staying in one place when before it moved all over the tank. I don't know if this caused the nitrate spike, or was because of it.

Did I make phosphates a limiting nutrient which caused the nitrates to go up?

I've since turned off the GFO reactor and added carbon. I'll test again tomorrow and see if the nitrates go down.

System info:

40 gallons with sump
Bioreactor with protein skimmer
170ppm alk (Hanna)
420ppm calcium (Hanna)
1.026 SG (refractometer)
Over 1500ppm magnesium (this is also high - I started a separate thread about this.)

 

[bertoni]

10 ppm of nitrate should be safe for most any animal. I suspect that the changes are coincidental to the nitrate level changes. On the other hand, too much GFO seems to lead to problems over the longer term, and the increase in the nitrate level might be related, although that's hard to determine. I think that turning off the GFO reactor was appropriate. I'd just monitor the phosphate and nitrate levels for a while, to see what happens.

 

[Hockeynut120]

I also think taking your GFO off line was the right thing to do I have found GFO to do more harm then good in most cases.
When my phosphate gets a little high instead of trying to lower with GFO I first try an additional WC.
I speak of my own experiences some run GFO with no apparent problems. remember reactions even at a small levels take time to become apparent so go slow with trying to bring down levels. Good luck

 

[CatWhispurrer]

I also think taking your GFO off line was the right thing to do I have found GFO to do more harm then good in most cases.
When my phosphate gets a little high instead of trying to lower with GFO I first try an additional WC.
I speak of my own experiences some run GFO with no apparent problems. remember reactions even at a small levels take time to become apparent so go slow with trying to bring down levels. Good luck

Are you running bio-pellets or dosing carbon instead of running GFO?

 

[Hockeynut120]

Non of the above I balance through water changes. I do dose a maintenance dose of special blend and also night out on waterchanges that's about it nitrate 10 phosphate .02

 

[swk]

Were the high po4 numbers causing problems? My po4 reads about .1 and my sps have never looked better. I have a bit more algae, but other than that no issues.

 

[CatWhispurrer]

Were the high po4 numbers causing problems? My po4 reads about .1 and my sps have never looked better. I have a bit more algae, but other than that no issues.

Just a brownish-green algae on the glass that needed to be cleaned with a magnet cleaner every couple days. It was starting to grow on the top of some parts of the sand bed as well, although I put an end to that with a sand dollar and a little conch.

From what I've been reading, .01 to .03 is ideal, but somebody can correct me if I'm wrong. It seems to me, at least in my case, I went from too high to too low too quickly lol.

 

[Hockeynut120]

Just a brownish-green algae on the glass that needed to be cleaned with a magnet cleaner every couple days. It was starting to grow on the top of some parts of the sand bed as well, although I put an end to that with a sand dollar and a little conch.

From what I've been reading, .01 to .03 is ideal, but somebody can correct me if I'm wrong. It seems to me, at least in my case, I went from too high to too low too quickly lol.

Hence the problem with GFO from to high to to low to quickly slow is always better from bad to good or good to bad

 

[bertoni]

I don't think we know what is idea, and different corals definitely will prefer different conditions. That said, levels below 0.03 ppm or so usually seem to be fine, although some people do report problems when the level becomes unmeasurable with our equipment.

Sudden changes in the phosphate level also seem to cause problems for some tanks, but not others. I'm not sure exactly what might be happening, but I suspect we'd need a very high-precision and high-accuracy phosphate measuring method to learn much.