Phosphate Steadily & Rapidly Dropping

[splunty]

Trying to understand reason for sudden, rapid dropping of phosphates:

2024/9/1 no3=5.8 po4=.09
2024/9/5 no3=9.7 po4=.10
2024/9/8 no3=9.0 po4=.09
2024/9/11 no3=9.0 po4=.08
2024/9/13 no3=10 po4=.10 (20% water change after testing)
2024/9/15 no3=5.3 po4=.09
2024/9/17 no3=7.0 po4=.07
2024/9/18 no3=5.6 po4=.03

Nitrates and phosphates have both held ranges (5-10, .03-.10) for 7 months until this event. I am testing with both Hanna and Salifert (the latter just to sanity check) every couple of days just to see the effects of the fluconazole. Changes:

2024/9/5 started raising salinity from 1.0245 to 1.0260 via ATO * (finished 9/18)
2024/9/11 dosed fluconazole **
2024/9/14 switched from Brightwell 2-part to B-Ionic 2-part ***
2024/9/16 cleaned as normal except did NOT touch white, dead bryopsis

* Testing with well-calibrated refractometer, Hanna salinity tester and glass hydrometer.
** Bryopsis absolutely exploded after I unwittingly tried to scrape some out thinking it was GHA.
*** Anyone else absolutely hate Brightwell's bottles? The caps always leak. B-Ionic FTW.

The tank looks cleaner than normal for sure. There's some green hair algae on one rock that looks like it has for weeks, and a tiny patch of red (2mm?) that looks like cyano on the glass under the sand that I didn't touch yet. Normal amount of sponge growth in the heater chamber and a dozen or so pineapples under the rocks that I can see. Livestock all appears normal. Feeding normally. No skimmer. The only filter is filter floss in the first chamber, which is replaced daily.

Edit: Coralline growth has also been increasing but there's not enough to cause any issues I don't think. I would estimate there's a total of 2 square inches now, only on the rocks and scattered around.

That's all I can think of - basically just trying to get some kind of grasp on what I did to cause the phosphates to drop that quickly. Unexpected result of killing off the bryopsis? Something else suddenly growing that I can't see? Salinity increase? B-ionic?

Plan is to keep testing and if it bottoms out, very slowly start dosing po4 until I get a reading again.

Any thoughts?

 

[Dan_P]

Trying to understand reason for sudden, rapid dropping of phosphates:

2024/9/1 no3=5.8 po4=.09
2024/9/5 no3=9.7 po4=.10
2024/9/8 no3=9.0 po4=.09
2024/9/11 no3=9.0 po4=.08
2024/9/13 no3=10 po4=.10 (20% water change after testing)
2024/9/15 no3=5.3 po4=.09
2024/9/17 no3=7.0 po4=.07
2024/9/18 no3=5.6 po4=.03

Nitrates and phosphates have both held ranges (5-10, .03-.10) for 7 months until this event. I am testing with both Hanna and Salifert (the latter just to sanity check) every couple of days just to see the effects of the fluconazole. Changes:

2024/9/5 started raising salinity from 1.0245 to 1.0260 via ATO * (finished 9/18)
2024/9/11 dosed fluconazole **
2024/9/14 switched from Brightwell 2-part to B-Ionic 2-part ***
2024/9/16 cleaned as normal except did NOT touch white, dead bryopsis

* Testing with well-calibrated refractometer, Hanna salinity tester and glass hydrometer.
** Bryopsis absolutely exploded after I unwittingly tried to scrape some out thinking it was GHA.
*** Anyone else absolutely hate Brightwell's bottles? The caps always leak. B-Ionic FTW.

The tank looks cleaner than normal for sure. There's some green hair algae on one rock that looks like it has for weeks, and a tiny patch of red (2mm?) that looks like cyano on the glass under the sand that I didn't touch yet. Normal amount of sponge growth in the heater chamber and a dozen or so pineapples under the rocks that I can see. Livestock all appears normal. Feeding normally. No skimmer. The only filter is filter floss in the first chamber, which is replaced daily.

Edit: Coralline growth has also been increasing but there's not enough to cause any issues I don't think. I would estimate there's a total of 2 square inches now, only on the rocks and scattered around.

That's all I can think of - basically just trying to get some kind of grasp on what I did to cause the phosphates to drop that quickly. Unexpected result of killing off the bryopsis? Something else suddenly growing that I can't see? Salinity increase? B-ionic?

Plan is to keep testing and if it bottoms out, very slowly start dosing po4 until I get a reading again.

Any thoughts?

I see one low number. Because your numbers are at the low end of the Hanna Checker, we need to wait for a few more measurements to declare a trend. Algae growth can be a culprit for phosphate depletion.

 

[Salty_Northerner]

My system is 14 months old and I still have po4 really low. I do weekly 10% WC and a day or so later the po4 sits at 2ppb or .006 (0) and I always have to add a 1/4 tsp of reefroids to bring it up. Usually in 2 days I'll check and it's generally at .08-.12ppm

I'm still stumped on why is bottoming out. The rock is 22 months old so it's a mystery I can't figure out :/

 

[cillam]

I have been dealing with trying to get my phosphates up.

From what I have read, phosphates will bind to the rock and reach equilibrium with what is in the water, so if the levels are higher in the water than in the rock it binds to the rock, if it is lower in the water than in the rock it leaches from the rock to the water.

Maybe your rocks have little bound phosphates.

Personally I am dosing phosphates dailey to try and get them up, I stopped with my 2 weekly 20% change and now only do a water change every 4 weeks at 20% until my phosphates get up and stay at .06

Unfortunately my nitrates are higher at around 50 so I am also carbon dosing to bring those down and in term dosing more neophos.

Algae will also use phosphates like all other living things, but it sounds like you dont have much bound phosphate in the rock.

 

[splunty]

Thank you everyone for the thoughts.

While I am not confident that there isn't any testing error at all, I do feel confident that Phosphates are dropping rapidly as a result of something(s) I have done. While thinking about this over a glass of scotch (mmm, scotch) last night:

- Since I was worried about a nutrient spike after the Bryopsis died off, I was very careful feeding the last several days. About half my feeding is pellets, which I suspect are high in phosphate. So I upset the balance there, even if slightly.

- Since I was worried about spreading the bryposis I avoided touching it so it would just "melt away". So I basically skipped a cleaning and then when I did clean, I didn't touch the areas where the Bryopsis was... in other words, I allowed other algae to grow even if I didn't necessarily see it.

- The coralline algae growth has actually boomed. I can't see it with my eyes very well, but the CCD on my cell sees it.

@cillam I am obviously not the expert, but I suspect carbon dosing without water changes will deplete Phosphates faster than no dosing with water changes.

 

[splunty]

Phosphates continued to read .03 for days and now have bottomed out at zero. The water in both kits (Hanna, Salifert) is visibly just clear -- I can't detect a tint at all.

I dosed enough PO4 (Aquaforest Labs) to supposedly raise to .01 ... after doing so and waiting 15 minutes, the Hanna tester still reads zero, but I am able to see (or perhaps imagine) a hint of tint in the Salifert test.

So at a loss here.

 

[Randy Holmes-Farley]

It doesn’t look like a big drop to me. I’d just feed more or dose N and P. Trying to understand reasons for every observation can be a fruitless challenge.

Don’t bother with tiny phosphate doses. Lots will bind to rock and sand. I’d use at least 0.05 ppm per day, and more may be needed.

 

[Reefahholic]

I wouldn’t call that rapid.

What rock was used in this tank.?

 

[Reefahholic]

My system is 14 months old and I still have po4 really low. I do weekly 10% WC and a day or so later the po4 sits at 2ppb or .006 (0) and I always have to add a 1/4 tsp of reefroids to bring it up. Usually in 2 days I'll check and it's generally at .08-.12ppm

I'm still stumped on why is bottoming out. The rock is 22 months old so it's a mystery I can't figure out :/

Water changes aren’t helping. You need to dose, skim dry, add more fish, etc.

 

[gbroadbridge]

Trying to understand reason for sudden, rapid dropping of phosphates:

2024/9/1 no3=5.8 po4=.09
2024/9/5 no3=9.7 po4=.10
2024/9/8 no3=9.0 po4=.09
2024/9/11 no3=9.0 po4=.08
2024/9/13 no3=10 po4=.10 (20% water change after testing)
2024/9/15 no3=5.3 po4=.09
2024/9/17 no3=7.0 po4=.07
2024/9/18 no3=5.6 po4=.03

Nitrates and phosphates have both held ranges (5-10, .03-.10) for 7 months until this event. I am testing with both Hanna and Salifert (the latter just to sanity check) every couple of days just to see the effects of the fluconazole. Changes:

2024/9/5 started raising salinity from 1.0245 to 1.0260 via ATO * (finished 9/18)
2024/9/11 dosed fluconazole **
2024/9/14 switched from Brightwell 2-part to B-Ionic 2-part ***
2024/9/16 cleaned as normal except did NOT touch white, dead bryopsis

* Testing with well-calibrated refractometer, Hanna salinity tester and glass hydrometer.
** Bryopsis absolutely exploded after I unwittingly tried to scrape some out thinking it was GHA.
*** Anyone else absolutely hate Brightwell's bottles? The caps always leak. B-Ionic FTW.

The tank looks cleaner than normal for sure. There's some green hair algae on one rock that looks like it has for weeks, and a tiny patch of red (2mm?) that looks like cyano on the glass under the sand that I didn't touch yet. Normal amount of sponge growth in the heater chamber and a dozen or so pineapples under the rocks that I can see. Livestock all appears normal. Feeding normally. No skimmer. The only filter is filter floss in the first chamber, which is replaced daily.

Edit: Coralline growth has also been increasing but there's not enough to cause any issues I don't think. I would estimate there's a total of 2 square inches now, only on the rocks and scattered around.

That's all I can think of - basically just trying to get some kind of grasp on what I did to cause the phosphates to drop that quickly. Unexpected result of killing off the bryopsis? Something else suddenly growing that I can't see? Salinity increase? B-ionic?

Plan is to keep testing and if it bottoms out, very slowly start dosing po4 until I get a reading again.

Any thoughts?

Those phosphate readings are all pretty reasonable and I wouldn't call it a sudden drop.

Obviously you've changed the tank and it will take time to for it to find a new equilibrium.

I'd just dose phosphate until it settles, bearing in mind that carbonate structures in the tank will bind much of what you dose.

 

[splunty]

I wouldn’t call that rapid.

What rock was used in this tank.?

Hey, 'holic. The rock is Marco Rock.

I had a post back in February when the opposite thing happened - steady months of trace detection and then a rise to 1.5 in a couple of days. GFO brought it back down, or at least helped.

Then after 7 months of holding steady, there is this opposite event, where I went from ~.9 to zero in a few days.

What I learned from reading a dozen threads about these type of events is that rock (and sand) can absorb and leach PO4 and, well, stay calm. The answer is always here on r2r already.

Thank you for responding!

 

[Reefahholic]

Hey, 'holic. The rock is Marco Rock.

Yep, that rock can be a nightmare and IMO one of the slowest most difficult problematic dry rock choices on the market.

It can definitely bind phosphate for months before it saturates which can sometimes be quite aggressive and really screw a tank up.

Several of us have had issues and trashed it. Mine is sitting in the bottom of a river right now. A few friends trashed theirs also.

 

[gbroadbridge]

Yep, that rock can be a nightmare and IMO one of the slowest most difficult problematic dry rock choices on the market.

It can definitely bind phosphate for months before it saturates which can sometimes be quite aggressive and really screw a tank up.

Several of us have had issues and trashed it. Mine is sitting in the bottom of a river right now. A few friends trashed theirs also.

Others of course have no problems with it.

It's the magician, not the wand

 

[splunty]

Yep, that rock can be a nightmare and IMO one of the slowest most difficult problematic dry rock choices on the market.

It can definitely bind phosphate for months before it saturates which can sometimes be quite aggressive and really screw a tank up.

Several of us have had issues and trashed it. Mine is sitting in the bottom of a river right now. A few friends trashed theirs also.

Well, I definitely won't be doing Marco Rock again ... although I do like the idea of quarry rock, there must be some better ecologically sustainable choices which is why I chose MR in the first place.

Luckily, I don't have room for another tank in my house (lol!) so there's that.

 

[Reefahholic]

Others of course have no problems with it.

It's the magician, not the wand

I’ve had decent tanks with Marco. They just take twice as long as, and get stuck in stupid for 14-24 months. I’ll never use it again unless in the ocean for minimal of 1.5-2 years. Even then I’d avoid it if possible. Unfortunately the only LR choices we really have in the US is all Florida Quarried rock from Gulf of Mexico or Florida Keys. All of it is the same as Marco. Same Limestone quarries.