jedimaster1138
Community Member
For the better part of the last 16 to 18 months, I've had horrible problems with my reef when it comes to stony corals. Acropora, seriatopa, birdnests, some montipora etc. Essentially any new SPS last...a few weeks to a few months in my reef before they develop brown algae on their tips, or just dump their polyps altogether prior to a complete necrosis event. Sometimes it happens a few days or even hours after introduction, sometimes a couple months later. It seems to depend heavily on the species and particular piece too. It's not bugs, aefw or anything biological. Some acro have grown out well for me and show tons of color and PE. Some just crumble. I've lost things like green birdnests as well as m. digitatas, seriatoporas... on and on. I've been thinking about this in the last day, because something interesting just happened, which has led me here to the land of science. 
Brief background - in January or so of 2014 I switched to a particular brand of salt that i later discovered was mixing up with phosphate levels anywhere from 0.28 to 0.35 ppm. I didn't discover this until after I had performed weekly - ish 10g water changes totally over 300g worth of this salt. This went on for about 9 months till I saw a forum post suggesting that this brand of salt had issues and then I tested my own newly made up water and was horrified. At the time I was so frustrated at the problems I had been having that went I found out the salt was "bad" I nearly through it out the window. I've since been using a different brand that I test every time I get a new box, and is thankfully showing 0 PO4 and appropriate alk/ca/mag, However, I've continued to have issues with my reef, mostly in terms of a complete inability to keep most SPS corals alive, growing and/or colored up. Some however have done much better, and LPS have completely bounced back. PO4 levels remain very high though. On an average day, say around 0.36 ppm. It can run up over 0.50 once GFO is exhausted and as low as 0.25 when its fresh.
Anyway, here is the hypothesis i've come up with tonight:
The problems I've been having with SPS corals are actually not solely attributable to extremely high phosphate levels over the last 16 months, but both to elevated phosphate and alkalinity swings that are hard to detect because they are quick and those alkalinity swings are in fact due to the phosphate levels causing stony coral calcification to pause, or otherwise slow down to the point where alkalinity rises to detrimental levels.
Detail:
When "things go bad" in my reef, it's noticeable as browning on the tips and occasionally other parts of various acropora and other SPS coral. In some cases this leads to complete STN/RTN, polyp retraction, complete loss of color etc. I've shown pictures of my troubled SPS to people in the past, and the conclusion they always reach is "that looks like tip burn due to high alkalinity". However, I always refute that idea because I've never seen dKH over 7 which is frustrating as I dose tons of kalkwasser and soda ash (BRS 2-part) into the reef. But perhaps it's the case that I'm just not detecting the alkalinity jump to "tip burning levels" because, for lack of a better way to put it, the swing high is just too rapid and I miss it because I don't test alkalinity every day. Also, my system has never been "ULNS" - nitrate is around 10-20 as well. I feed heavy as well and have a pretty heavy bioload.
So this begs the obvious question - why is alkalinity swinging? OK so I dose a lot of two different products to maintain both calcium an alkalinity yet I can never get much above 7 dKH and 350-400 ppm calcium. The next question people always ask - magnesium low? Nope, isn't a problem, It usually reads around 1400 ppm. I always blamed the inability to keep alk/ca in the desired range because it's a 120g reef with a bunch of big clams and I'm trying to maintain alk/ca with just 2 - part and/or kalkwasser.
But...
Could the alkalinity swing be some what directly due to the phosphate somehow and that's where the real damage is being done to the corals?
Phosphate is high still. Really high. > 0.36 ppm, tested with 2 different kinds of kits and Triton. I've seen it as high as 0.50. Now I know very high levels of PO4 can stop calcification, which explains the lack of growth in the SPS, so there's that. But the die offs? The burnt tips? With alkalinity showing around 7 dKH? It just didn't add up. All I could blame was PO4, so I kept on changing GFO every few weeks and PO4 levels drop some for a day or two, to say around 0.25, if i'm fortunate, but then moves right back up a few days later, presumably because the GFO exhausts rapidly.
So, where am I going with this OK - phosphate is causing calcification to stop, "pausing" the reef, well some of it. The stony corals cease taking up carbonate molecules. This then leads to a lot of free floating carbonate in the water which then results in ticked off acropora in the form of burnt tips. This high alkalinity level might only go on for a day or so, maybe even hours. I don't know as I don't have real time dKH levels. I also don't totally understand this mechanism, why/how high levels of carbonate cause such strife to SPS in the form of burnt tips etc but, yeah. That's my theory and I'm open to comments about it.
A couple other observations...
I can tell when a pause, or crash, or SPS frying event is about to happen via the pH probe. pH will creep up as I'll watch it daily on the Apex . A few months ago the wife and I were on vacation (ironically snorkeling reefs in Hawaii) and my Apex buzzed me to say the pH was > 8.50. Huh? That's weird, especially with the apartment buttoned up tight for winter. If anything it should be low. We get back a few days later and sure enough, there was a crash event. Lots of brown algae on the tips of lots of different SPS frags and colonies, but not all. Levels were all normal, especially alkalinity (first thing i checked) but the damage had been done. Interesting. And adds up. The reef wasn't using the alkalinity that was being dosed, and that excess drove up pH.
It's also cyclical and I think it's tied to GFO exhaustion and replacement. Wednesday night I changed GAC and GFO. Probably a cup of ROX and a few spoons of GFO. Not much at all (more on why in a minute) Thursday night I noticed brown/burnt tips on a few acropora that were just fine the night before. Suspicious. Coincidence?
So is this what's happening? Phosphate rises and rises as GFO is exhausted over a period of a few weeks. Eventually it reaches a point where calcification stops (ps what's that point?) Alkalinity is still being dosed at the same, high level, which normally struggles to keep dKH around 7. With calcification stopping, the carbonate ions aren't being taken in by the corals, the level rises to what I guess is detrimental levels, presumably way higher than 9 dKH. Tonight I measured it at 9.6 Last week, with things "normal" it was 7. I didn't change anything, increase dosing etc. Nothing changed on my end. Clearly the reef just stopped using the alkalinity I was putting in.
The thing that's wrong with my scenario is ... what does the GFO have to do with it? Why does the replacement of NEW GFO seem to be the trigger that started the burnt tips the next night? Or is that just coincidence?
Another wrinkle...Calcium - i still can't keep calcium above 350-380 ish. Is the calcium binding with the phosphate in abundance in the water column and precipitating some way that I can't see?
So ... now what? I'm somewhat inclined to stop ALL dosing as I wonder while phosphate is a problem, I'm actually making it dramatically worse, and actually causing the coral death events, by dosing alkalinity and/or calcium when the reef doesn't need it, even though that's only say, 10% of the time, and the other 90% it really does take it up? Perhaps I shouldn't dose anything until I get phosphate down, if I can. I just got a big bottle of NOPOX and was going to start on that daily to see if it can fight off this PO4 issue with bacteria, not constant use of GFO and these cycles of pain.
Comments are strongly urged...
Sorry this was long. I think I'm thinking out loud a lot. Just tired of throwing out white coral skeletons...
.
Phosphate had risen high, it was around 0.40 one day last week. I was nearing the end of the GFO cycle then. I started dosing the NOPOX Monday and also changed GFO Wednesday, albeit a small amount. Prior to last night, the reef must have been in its "paused" state, with carbonate not being absorbed by the stony corals. Since the media change, and possibly also because of the NOPOX kicking in, phosphate dropped, at least somewhat.
Brief background - in January or so of 2014 I switched to a particular brand of salt that i later discovered was mixing up with phosphate levels anywhere from 0.28 to 0.35 ppm. I didn't discover this until after I had performed weekly - ish 10g water changes totally over 300g worth of this salt. This went on for about 9 months till I saw a forum post suggesting that this brand of salt had issues and then I tested my own newly made up water and was horrified. At the time I was so frustrated at the problems I had been having that went I found out the salt was "bad" I nearly through it out the window. I've since been using a different brand that I test every time I get a new box, and is thankfully showing 0 PO4 and appropriate alk/ca/mag, However, I've continued to have issues with my reef, mostly in terms of a complete inability to keep most SPS corals alive, growing and/or colored up. Some however have done much better, and LPS have completely bounced back. PO4 levels remain very high though. On an average day, say around 0.36 ppm. It can run up over 0.50 once GFO is exhausted and as low as 0.25 when its fresh.
Anyway, here is the hypothesis i've come up with tonight:
The problems I've been having with SPS corals are actually not solely attributable to extremely high phosphate levels over the last 16 months, but both to elevated phosphate and alkalinity swings that are hard to detect because they are quick and those alkalinity swings are in fact due to the phosphate levels causing stony coral calcification to pause, or otherwise slow down to the point where alkalinity rises to detrimental levels.
Detail:
When "things go bad" in my reef, it's noticeable as browning on the tips and occasionally other parts of various acropora and other SPS coral. In some cases this leads to complete STN/RTN, polyp retraction, complete loss of color etc. I've shown pictures of my troubled SPS to people in the past, and the conclusion they always reach is "that looks like tip burn due to high alkalinity". However, I always refute that idea because I've never seen dKH over 7 which is frustrating as I dose tons of kalkwasser and soda ash (BRS 2-part) into the reef. But perhaps it's the case that I'm just not detecting the alkalinity jump to "tip burning levels" because, for lack of a better way to put it, the swing high is just too rapid and I miss it because I don't test alkalinity every day. Also, my system has never been "ULNS" - nitrate is around 10-20 as well. I feed heavy as well and have a pretty heavy bioload.
So this begs the obvious question - why is alkalinity swinging? OK so I dose a lot of two different products to maintain both calcium an alkalinity yet I can never get much above 7 dKH and 350-400 ppm calcium. The next question people always ask - magnesium low? Nope, isn't a problem, It usually reads around 1400 ppm. I always blamed the inability to keep alk/ca in the desired range because it's a 120g reef with a bunch of big clams and I'm trying to maintain alk/ca with just 2 - part and/or kalkwasser.
But...
Could the alkalinity swing be some what directly due to the phosphate somehow and that's where the real damage is being done to the corals?
Phosphate is high still. Really high. > 0.36 ppm, tested with 2 different kinds of kits and Triton. I've seen it as high as 0.50. Now I know very high levels of PO4 can stop calcification, which explains the lack of growth in the SPS, so there's that. But the die offs? The burnt tips? With alkalinity showing around 7 dKH? It just didn't add up. All I could blame was PO4, so I kept on changing GFO every few weeks and PO4 levels drop some for a day or two, to say around 0.25, if i'm fortunate, but then moves right back up a few days later, presumably because the GFO exhausts rapidly.
So, where am I going with this OK - phosphate is causing calcification to stop, "pausing" the reef, well some of it. The stony corals cease taking up carbonate molecules. This then leads to a lot of free floating carbonate in the water which then results in ticked off acropora in the form of burnt tips. This high alkalinity level might only go on for a day or so, maybe even hours. I don't know as I don't have real time dKH levels. I also don't totally understand this mechanism, why/how high levels of carbonate cause such strife to SPS in the form of burnt tips etc but, yeah. That's my theory and I'm open to comments about it.
A couple other observations...
I can tell when a pause, or crash, or SPS frying event is about to happen via the pH probe. pH will creep up as I'll watch it daily on the Apex . A few months ago the wife and I were on vacation (ironically snorkeling reefs in Hawaii) and my Apex buzzed me to say the pH was > 8.50. Huh? That's weird, especially with the apartment buttoned up tight for winter. If anything it should be low. We get back a few days later and sure enough, there was a crash event. Lots of brown algae on the tips of lots of different SPS frags and colonies, but not all. Levels were all normal, especially alkalinity (first thing i checked) but the damage had been done. Interesting. And adds up. The reef wasn't using the alkalinity that was being dosed, and that excess drove up pH.
It's also cyclical and I think it's tied to GFO exhaustion and replacement. Wednesday night I changed GAC and GFO. Probably a cup of ROX and a few spoons of GFO. Not much at all (more on why in a minute) Thursday night I noticed brown/burnt tips on a few acropora that were just fine the night before. Suspicious. Coincidence?
So is this what's happening? Phosphate rises and rises as GFO is exhausted over a period of a few weeks. Eventually it reaches a point where calcification stops (ps what's that point?) Alkalinity is still being dosed at the same, high level, which normally struggles to keep dKH around 7. With calcification stopping, the carbonate ions aren't being taken in by the corals, the level rises to what I guess is detrimental levels, presumably way higher than 9 dKH. Tonight I measured it at 9.6 Last week, with things "normal" it was 7. I didn't change anything, increase dosing etc. Nothing changed on my end. Clearly the reef just stopped using the alkalinity I was putting in.
The thing that's wrong with my scenario is ... what does the GFO have to do with it? Why does the replacement of NEW GFO seem to be the trigger that started the burnt tips the next night? Or is that just coincidence?
Another wrinkle...Calcium - i still can't keep calcium above 350-380 ish. Is the calcium binding with the phosphate in abundance in the water column and precipitating some way that I can't see?
So ... now what? I'm somewhat inclined to stop ALL dosing as I wonder while phosphate is a problem, I'm actually making it dramatically worse, and actually causing the coral death events, by dosing alkalinity and/or calcium when the reef doesn't need it, even though that's only say, 10% of the time, and the other 90% it really does take it up? Perhaps I shouldn't dose anything until I get phosphate down, if I can. I just got a big bottle of NOPOX and was going to start on that daily to see if it can fight off this PO4 issue with bacteria, not constant use of GFO and these cycles of pain.
Comments are strongly urged...
Sorry this was long. I think I'm thinking out loud a lot. Just tired of throwing out white coral skeletons...
.
Phosphate had risen high, it was around 0.40 one day last week. I was nearing the end of the GFO cycle then. I started dosing the NOPOX Monday and also changed GFO Wednesday, albeit a small amount. Prior to last night, the reef must have been in its "paused" state, with carbonate not being absorbed by the stony corals. Since the media change, and possibly also because of the NOPOX kicking in, phosphate dropped, at least somewhat.
