Corals dying

[Delphinus]

Sounds totally plausible to me..

Might not be an issue in this case but something to think about as well as that a zero PO4 reading isn't always "really zero."

Early on it was claimed with biopellets that they reduce PO4 as well as NO3. However, this has not been my experience (I do use and have used pellets on tanks and have seen good NO3 reduction or elimination with them. But not PO4.) It's been claimed more recently that they can only reduce PO4 as long as they have NO3 to reduce. Unfortunately I can't claim any anecdotal evidence to support or dispute that, so that may well be the case for all I know, but ultimately, regardless if that is true or not, pellets do have a limited ability to remove PO4. So even with pellet use, having GFO on the tank is a good idea.

It's been a while since I've done my reading on this, but if you go back over the years of reef chemistry postings by Randy Holmes-Farley and others, I think you can find more info, but from what I recall: basically you have organic phosphate and inorganic phosphate. We can only test for inorganic phosphate, we can't test for organic phosphate, but it's only organic phosphate we need concern ourselves. So we test the inorganics and hope for the best that there is a proportional relationship between the two. This might not always be the case. So basically unless you have something proven in place for PO4 removal (GFO or lanthanum or whatever), you might have PO4 even if you test it out and get a zero (or nominal) reading. So even if you think PO4 isn't a problem, having GFO (or similar product) on the tank regardless, is a good idea.

(I just wish GFO was cheaper...)

[Seriak]

Okay,

But I heard the correlation goes both ways. If you don't have enough phosphates, bio pellets will not be able to reduce nitrates and since I have high nitrates and supposedly low phosphates, I was thinking I didn't want to run GFO until my nitrates came down. I hope to pick up my GFO from Eli soon, but I wasn't going to use it until my nitrates levels were closer to 0. Should I start it up earlier?

[asylumdown]

If the bacteria in the biopellets are really using nutrients according to the redfield ratio, they use 16 times less phosphorous than nitrogen. You can have very low Phosphate levels and still have nitrate reduction taking place in your pellets. If you're really worried, you should start with a very small amount of GFO so that the levels don't plummet to zero in a few hours (that's good practice anyway).

[Seriak]

Originally Posted by asylumdown

If the bacteria in the biopellets are really using nutrients according to the redfield ratio, they use 16 times less phosphorous than nitrogen. You can have very low Phosphate levels and still have nitrate reduction taking place in your pellets. If you're really worried, you should start with a very small amount of GFO so that the levels don't plummet to zero in a few hours (that's good practice anyway).

Yeah, but if I have 0.02 to 0.03 Phosphates atm and >25 Nitrates (which could mean 100 for all I know) I would almost like to increase my phosphates in the short term to reduce my nitrates faster. Or at least I think I do.

[Delphinus]

Maybe just hold off on the gfo for now and monitor the NO3. If it looks like it's coming down, leave it as-is but maybe once it gets to 10 or so (I'm just pulling this number out of the air arbitrarily) then go ahead and put the GFO on.

[asylumdown]

Originally Posted by Delphinus

Maybe just hold off on the gfo for now and monitor the NO3. If it looks like it's coming down, leave it as-is but maybe once it gets to 10 or so (I'm just pulling this number out of the air arbitrarily) then go ahead and put the GFO on.

yah I think this is the best advice. 0.02-0.03 phosphate isn't bad, actually some people strive for that level.

The pellets take a while to do their thing.

[daniella3d]

I would be happy if I had that level of phosphate in my tank. It's at 0.1 and has been for a long time.

Originally Posted by asylumdown

yah I think this is the best advice. 0.02-0.03 phosphate isn't bad, actually some people strive for that level.

The pellets take a while to do their thing.

[Reef Pilot]

Originally Posted by daniella3d

I would be happy if I had that level of phosphate in my tank. It's at 0.1 and has been for a long time.

Do you run GFO?

I can pretty tell how much P04 I have by how fast the algae grows on my glass. When it gets up to .1, I change my GFO, and then it is again down to between 0 and .04. It slowly creeps up over about 2 months, and then I change it.

I only use about 200 ml of HC GFO in my reactor. I also give my reactors (carbon and GFO) an air bubble flush when I clean the 1st canister, which then stirs up the GFO, and the levels drop down again. But when the P04 stays up, then I know it is time to change it.

I also run a bio pellet reactor (N03 always zero now), so it may take out a bit of P04, too. Lately, though, I have really let my bio pellets run low in this reactor (only about 200 ml in it now), but will not add any until I start seeing some nitrates again.

And to think that 2 years ago, this same tank had over 50 ppm N03 (as high as 100 at one time), and P04 at 1.0.

[asylumdown]

Originally Posted by Delphinus

Sounds totally plausible to me..

Might not be an issue in this case but something to think about as well as that a zero PO4 reading isn't always "really zero."

Early on it was claimed with biopellets that they reduce PO4 as well as NO3. However, this has not been my experience (I do use and have used pellets on tanks and have seen good NO3 reduction or elimination with them. But not PO4.) It's been claimed more recently that they can only reduce PO4 as long as they have NO3 to reduce. Unfortunately I can't claim any anecdotal evidence to support or dispute that, so that may well be the case for all I know, but ultimately, regardless if that is true or not, pellets do have a limited ability to remove PO4. So even with pellet use, having GFO on the tank is a good idea.

It's been a while since I've done my reading on this, but if you go back over the years of reef chemistry postings by Randy Holmes-Farley and others, I think you can find more info, but from what I recall: basically you have organic phosphate and inorganic phosphate. We can only test for inorganic phosphate, we can't test for organic phosphate, but it's only organic phosphate we need concern ourselves. So we test the inorganics and hope for the best that there is a proportional relationship between the two. This might not always be the case. So basically unless you have something proven in place for PO4 removal (GFO or lanthanum or whatever), you might have PO4 even if you test it out and get a zero (or nominal) reading. So even if you think PO4 isn't a problem, having GFO (or similar product) on the tank regardless, is a good idea.

(I just wish GFO was cheaper...)

This is exactly why I take all my test kits with a grain of salt. My test kits have all read 0.00 phosphate and nitrate for months, and yet my coral and coraline algae still grows, there's some hair algae in my overflows that still grows, and I still need to clean the glass every day or so. When you enter in to a situation where all your nutrients are either in a form you can't test for, or they're dynamically taken up by something the second they're produced, you almost need to rely on what your tank is telling you than what you get from a test kit.

[reefwars]

Originally Posted by asylumdown

This is exactly why I take all my test kits with a grain of salt. My test kits have all read 0.00 phosphate and nitrate for months, and yet my coral and coraline algae still grows, there's some hair algae in my overflows that still grows, and I still need to clean the glass every day or so. When you enter in to a situation where all your nutrients are either in a form you can't test for, or they're dynamically taken up by something the second they're produced, you almost need to rely on what your tank is telling you than what you get from a test kit.

your getting 0.000 on the ultra low test kit?