Need some help with Phosphate levels - I cannot seem to keep them down

[alex21720]

Some background on the tank:
I bought this system (rock, water, and livestock included) about 5 months ago. The tank had already been running for over a year before I got it. I don’t know what phosphate levels looked like when I first acquired it, since I didn’t yet own a Hanna ULR checker.


On day 3, I noticed a ton of aiptasia on one of the rocks. To deal with it, I pulled that rock, bleached it for a week, then conditioned it to make sure no chlorine remained before putting it back. This was also right around the time I started monitoring nutrients. I mention this because I’m curious if bleaching rock can cause phosphate to leach out later.


Phosphate history:
From that point on, I’ve consistently battled high phosphates. Initially, levels were above the Hanna ULR range (>0.9). Using PhosRX, I was able to bring them down to about 0.5, but I got tired of daily dosing and switched to running GFO in a filter sock. Even with GFO, it has been tough to keep phosphate under control since levels spike quickly once the media is exhausted or if I stop dosing PhosRX.


For reference, my nitrates usually sit around 10 ppm. I do weekly 5-gallon water changes on this 25-gallon tank. I’ve also had periods of battling hair algae and algae on the glass.


Example (this past week):

• PO4 started at 0.5 ppm
• After a few days of PhosRX, it read 0.0
• That day, I added fresh GFO in a filter sock
• Next day: 0.1 ppm
• Day after: 0.5 ppm
• Following day: 0.9 ppm (off the charts)

Livestock and feeding:
In the 25g tank I have:

• 2 small clowns
• 1 medium gramma
• 1 melanarus wrasse (came with the tank, can’t catch him to rehome)
• A few torches, hammers, frogspawns, zoas, and GSP
• Small CUC (hermits/snails, nothing dying off regularly that I can see)

I feed primarily frozen mysis, about 1 cube every 2–3 days, and occasionally Neptune Systems Cross Over Diet. I don’t target feed corals since I’ve been trying to limit nutrients. Overall, I don’t think I’m heavily overstocked.


Question:
Why are my phosphates climbing so high, so fast? Any help troubleshooting would be greatly appreciated.


Current idea / potential solution:
Since it’s an AIO tank without a sump, I’ve been considering running a chaeto reactor in line with a GFO reactor. My plan would be:

1. Pump water through a Phytotank Chaeto Reactor (link below).
2. From there, route it directly into a GFO media reactor (instead of just a bag in the filter sock).

The idea is that the chaeto would handle most of the phosphate uptake, and the GFO would act as a polisher so it doesn’t get depleted too quickly.


Has anyone tried a setup like this on an AIO system? Do you think this approach makes sense?


(Link: Phytotank Macroalgae Chaeto Reactor)

 

[bubbgee]

On AIO, po4 is hard to reduce. What did help me was kalk dosing for a while. Rocks potentially can release phosphates too (I learned that the hard way and bought live rock afterwards).

Your solution is sound. But also address the source of phosphate -- food, RODI, rock. Once you identify where it's coming from, the reduction will be way more easier.

 

[Lavey29]

Are you using anything like chemipure blue in your media basket? Chaeto won't do anything for phosphate but will reduce nitrates slightly.

 

[alex21720]

On AIO, po4 is hard to reduce. What did help me was kalk dosing for a while. Rocks potentially can release phosphates too (I learned that the hard way and bought live rock afterwards).

Your solution is sound. But also address the source of phosphate -- food, RODI, rock. Once you identify where it's coming from, the reduction will be way more easier.

Yeah I am worried it's coming from the rock, and I don't know of a good way to swap out my rocks. Is it sufficient to just buy live rock and hot swap it straight in? Or should I frag all of my corals off onto plugs/frag rags and slowly swap out my rock on piece at a time? I don't see how anything else could be the source of the PO4, as it'll rise even when i dial back feeding to almost nothing.

As a side question - do you know how much lag there is in added phosphates resulting from overfeeding? If it takes days to see the effects in the PPM readings that could at least partially explain why I don't feel like the feeding is an issue, as i'll sometimes go 2 days without feeding and still see it rise drastically.

As for PO4 being difficult to reduce on an AIO, what makes it more difficult than a tank/sump to reduce phosphates? Is it just that adding in things like media reactors/fuges is more difficult?

 

[alex21720]

Are you using anything like chemipure blue in your media basket? Chaeto won't do anything for phosphate but will reduce nitrates slightly.

I am not. I've used chemipure blue but switched to straight GFO after i exhausted it.

So as far as nutrient export/uptake goes, I have the following:

1 bag of GFO, about 4 tbsps that I change out about once every 2 weeks. It's in my filter sock, but I have it off the bottom of the sock to help water flow through it. I know it's not ideal

I have a Sicce Shark 300 skimmer, that either I can't seem to get tuned right or it's just struggling to find stuff to pull from the water. It's been running for about a month and the best I can get out of it is a light brown watery "skimmate". The bubbles never even appear brown. If I tune it down I just get no overflow at all into the cup

And then I have about 20lbs of live rock with miscellanous corals
- 4 heads worth of torch
-4 heads worth of hammers/frogspawn/frammers
- a beefy duncan
- 2 Yuma Ricordea
- 1 small acro frag
- 1 small cyphastrea frag
- a bunch of zoas

 

[bubbgee]

Yeah I am worried it's coming from the rock, and I don't know of a good way to swap out my rocks. Is it sufficient to just buy live rock and hot swap it straight in? Or should I frag all of my corals off onto plugs/frag rags and slowly swap out my rock on piece at a time? I don't see how anything else could be the source of the PO4, as it'll rise even when i dial back feeding to almost nothing.

As a side question - do you know how much lag there is in added phosphates resulting from overfeeding? If it takes days to see the effects in the PPM readings that could at least partially explain why I don't feel like the feeding is an issue, as i'll sometimes go 2 days without feeding and still see it rise drastically.

As for PO4 being difficult to reduce on an AIO, what makes it more difficult than a tank/sump to reduce phosphates? Is it just that adding in things like media reactors/fuges is more difficult?

Yeah I swapped out the rocks when I was on my AIO. Also, maybe add polyplab genesis rocks in display temporarily to increase the nutrient consumption instead of live rock.

Lag-wise, I see a day or two. That's why when managing phosphates, you need to know the source and probably test daily until you have a handle on it.

As for PO4 being difficult to reduce on an AIO, what makes it more difficult than a tank/sump to reduce phosphates? Is it just that adding in things like media reactors/fuges is more difficult?
-- from my experience having AIO and a larger tank with sump, it's just water volume. It's easier to dilute with a larger water volume (i.e. huge water changes, a 50ml dose of neophos won't make a huge difference to a 100 gallon tank). That's why AIO nano and pico tanks are challenging. My success with AIO is limited to soft corals where I don't have to worry about nutrients or pH or even dosing. I don't even do water changes, just topping off with RODI.

A couple of tips I can give you on nutrient control for AIO tans, You can add the macro directly to the display until the nutrients are sucked out. Importantly, add a protein skimmer HOB that is oversized to skim out the particulates and food.

Note: all of the solutions can be temporary and removed once the po4 is under control for a while. You can always remove the macroalgae. You can remove the genesis rocks and you remove the HOB skimmer.

 

[Lavey29]

I found lanthium chloride is best for my phosphate but I wouldn’t be overly concerned with elevated phosphate. A lot of tanks here have elevated phosphate and look beautiful. As long as you have good nitrates it will be fine. My phosphate is typically .2. To .4 and nitrates 20. Your rocks are just leaching into the water. Eventually it will slow down.

 

[alex21720]

Yeah I swapped out the rocks when I was on my AIO. Also, maybe add polyplab genesis rocks in display temporarily to increase the nutrient consumption instead of live rock.

Lag-wise, I see a day or two. That's why when managing phosphates, you need to know the source and probably test daily until you have a handle on it.

As for PO4 being difficult to reduce on an AIO, what makes it more difficult than a tank/sump to reduce phosphates? Is it just that adding in things like media reactors/fuges is more difficult?
-- from my experience having AIO and a larger tank with sump, it's just water volume. It's easier to dilute with a larger water volume (i.e. huge water changes, a 50ml dose of neophos won't make a huge difference to a 100 gallon tank). That's why AIO nano and pico tanks are challenging. My success with AIO is limited to soft corals where I don't have to worry about nutrients or pH or even dosing. I don't even do water changes, just topping off with RODI.

A couple of tips I can give you on nutrient control for AIO tans, You can add the macro directly to the display until the nutrients are sucked out. Importantly, add a protein skimmer HOB that is oversized to skim out the particulates and food.

Note: all of the solutions can be temporary and removed once the po4 is under control for a while. You can always remove the macroalgae. You can remove the genesis rocks and you remove the HOB skimmer.

Makes sense - I appreciate your feedback. I have a nano skimmer in the AIO "sump" side. It's the Sicce shark 300 which I believe is oversized, but I can't seem to get it to actually skim out skimmate. The best I can achieve with it is a slight brown watery skimmate.

I'll consider trying the genesis rock and then may also use that to act as nutrient control/buffer as I pull and swap other rock for live rock.

 

[vetteguy53081]

Some background on the tank:
I bought this system (rock, water, and livestock included) about 5 months ago. The tank had already been running for over a year before I got it. I don’t know what phosphate levels looked like when I first acquired it, since I didn’t yet own a Hanna ULR checker.


On day 3, I noticed a ton of aiptasia on one of the rocks. To deal with it, I pulled that rock, bleached it for a week, then conditioned it to make sure no chlorine remained before putting it back. This was also right around the time I started monitoring nutrients. I mention this because I’m curious if bleaching rock can cause phosphate to leach out later.


Phosphate history:
From that point on, I’ve consistently battled high phosphates. Initially, levels were above the Hanna ULR range (>0.9). Using PhosRX, I was able to bring them down to about 0.5, but I got tired of daily dosing and switched to running GFO in a filter sock. Even with GFO, it has been tough to keep phosphate under control since levels spike quickly once the media is exhausted or if I stop dosing PhosRX.


For reference, my nitrates usually sit around 10 ppm. I do weekly 5-gallon water changes on this 25-gallon tank. I’ve also had periods of battling hair algae and algae on the glass.


Example (this past week):

• PO4 started at 0.5 ppm
• After a few days of PhosRX, it read 0.0
• That day, I added fresh GFO in a filter sock
• Next day: 0.1 ppm
• Day after: 0.5 ppm
• Following day: 0.9 ppm (off the charts)

Livestock and feeding:
In the 25g tank I have:

• 2 small clowns
• 1 medium gramma
• 1 melanarus wrasse (came with the tank, can’t catch him to rehome)
• A few torches, hammers, frogspawns, zoas, and GSP
• Small CUC (hermits/snails, nothing dying off regularly that I can see)

I feed primarily frozen mysis, about 1 cube every 2–3 days, and occasionally Neptune Systems Cross Over Diet. I don’t target feed corals since I’ve been trying to limit nutrients. Overall, I don’t think I’m heavily overstocked.


Question:
Why are my phosphates climbing so high, so fast? Any help troubleshooting would be greatly appreciated.


Current idea / potential solution:
Since it’s an AIO tank without a sump, I’ve been considering running a chaeto reactor in line with a GFO reactor. My plan would be:

1. Pump water through a Phytotank Chaeto Reactor (link below).
2. From there, route it directly into a GFO media reactor (instead of just a bag in the filter sock).

The idea is that the chaeto would handle most of the phosphate uptake, and the GFO would act as a polisher so it doesn’t get depleted too quickly.


Has anyone tried a setup like this on an AIO system? Do you think this approach makes sense?


(Link: Phytotank Macroalgae Chaeto Reactor)

Assuming numbers are true, I suggest adding a pouch of Chemipure blue or even Elite and doing 2-3 gallon water changes daily for the next two weeks. This step should take under 10 minutes daily
Skimmer and even algae scrubber will also help with control

 

[alex21720]

Assuming numbers are true, I suggest adding a pouch of Chemipure blue or even Elite and doing 2-3 gallon water changes daily for the next two weeks. This step should take under 10 minutes daily
Skimmer and even algae scrubber will also help with control

What does the chemipure blue/elite achieve that GFO wouldn't? And as for the small water changes, isn't that all just a temporary solution to manage and keep the levels low? In my experience, once I stop things like GFO and water changes things rise quickly, which tells me that there is a source that will consistently push out phosphates.

Unless there is a process by which keeping PO4 low for X amount of time does something to the chemistry of the tank that allows the backteria to then flourish and manage it better long-term?

 

[bubbgee]

Makes sense - I appreciate your feedback. I have a nano skimmer in the AIO "sump" side. It's the Sicce shark 300 which I believe is oversized, but I can't seem to get it to actually skim out skimmate. The best I can achieve with it is a slight brown watery skimmate.

I'll consider trying the genesis rock and then may also use that to act as nutrient control/buffer as I pull and swap other rock for live rock.

I would prefer a hob skimmer. I could never dial in the skimmer in those tiny chambers in the back anyway.

 

[alex21720]

I would prefer a hob skimmer. I could never dial in the skimmer in those tiny chambers in the back anyway.

Gotcha, did not know that the internal skimmers in an AIO would be tough to dial in. I'll look into a hob

 

[bubbgee]

What does the chemipure blue/elite achieve that GFO wouldn't? And as for the small water changes, isn't that all just a temporary solution to manage and keep the levels low? In my experience, once I stop things like GFO and water changes things rise quickly, which tells me that there is a source that will consistently push out phosphates.

Unless there is a process by which keeping PO4 low for X amount of time does something to the chemistry of the tank that allows the backteria to then flourish and manage it better long-term?

Goes back to the question where the PO4 is coming from. My experience is my RODI. I invested in a better filter and added extra DI resin chambers for good measure. I replaced the rocks leeching PO4 with live rock and replaced dry pellets and reef roids with benepets and frozen. I am at the point I am struggling keeping PO4 and NO3 up now.

Benepets do seem to reduce nutrients because of their formulation. You can also try that out too.

 

[Randy Holmes-Farley]

Chemipure blue cannot bind phosphate effectively from seawater, but GFO, as in the elite form of Chemipure will.

 

[Randy Holmes-Farley]

What does the chemipure blue/elite achieve that GFO wouldn't? And as for the small water changes, isn't that all just a temporary solution to manage and keep the levels low? In my experience, once I stop things like GFO and water changes things rise quickly, which tells me that there is a source that will consistently push out phosphates.

Unless there is a process by which keeping PO4 low for X amount of time does something to the chemistry of the tank that allows the backteria to then flourish and manage it better long-term?

Nope. It’s primarily the GFO in it that makes it bring down phosphate.

 

[alex21720]

Chemipure blue cannot bind phosphate effectively from seawater, but GFO, as in the elite form of Chemipure will.

Gotcha, so pure GFO is giong to be the best as far as media goes at removing PO4, correct? Is it even possible for it to be effective in a media bag in the filter sock? Or does it absolutely need to be in a reactor?

I also feel like its depleting faster than anticipated, but that also aligns some with the massive swings i'll see in a single day that lead me to believe my rocks are just dumping PO4 into the system

 

[bubbgee]

Gotcha, so pure GFO is giong to be the best as far as media goes at removing PO4, correct? Is it even possible for it to be effective in a media bag in the filter sock? Or does it absolutely need to be in a reactor?

I also feel like its depleting faster than anticipated, but that also aligns some with the massive swings i'll see in a single day that lead me to believe my rocks are just dumping PO4 into the system

Works best in a reactor. You could look into Innovative Marine desktop reactors for that purpose.

For me, the best for removing po4 is lanthanum chloride --too good that it can crash your tank when dosed improperly. Followed by GFO-- which also crashes a tank when you apply too much.

LC you need to apply almost every other day or so as it will let PO4 rise when it is consumed. GFO is a more gradual reduction in PO4 that can be monitored daily and shutdown off a reactor when it reaches your range.

 

[BryanM]

GFO just works better in a reactor, plenty of people just do what you''re doing, in a sock, totally fine.

I'm surprised it goes up THAT fast. That is the only puzzler to me here.

I would also suggest that you're not feeding enough for those fish. At least once a day, most of us prefer to feed fish 3-4x daily. Somewhat counter intuitive when you're trying to lower phos, but I don't like starving fish.

 

[alex21720]

GFO just works better in a reactor, plenty of people just do what you''re doing, in a sock, totally fine.

I'm surprised it goes up THAT fast. That is the only puzzler to me here.

I would also suggest that you're not feeding enough for those fish. At least once a day, most of us prefer to feed fish 3-4x daily. Somewhat counter intuitive when you're trying to lower phos, but I don't like starving fish.

To clarify, I do feed twice daily. Usually just straight mysis right now as i'm battling this. But up until recently i also used Neptune CD.

I had gone a couple days without feeding as I took a business trip and didn't feel it was worth setting up an auto-feeder when I was curious if feeding was contributing to the problem.

 

[areefer01]

I'm surprised it goes up THAT fast. That is the only puzzler to me here.

Rebound? Bound up in rock or substrate so equilibrium imbalance and it is released? Lower, released, repeat until the balance is found. Also part of that is as you allude to below with hobbyist finding their routine with feeding, export, etc.

I would also suggest that you're not feeding enough for those fish. At least once a day, most of us prefer to feed fish 3-4x daily. Somewhat counter intuitive when you're trying to lower phos, but I don't like starving fish.

I personally do not like the idea of feeding less. Sort of like me skipping a meal, no thank you. Fish forage throughout the day. Skipping a meal may make them forage a bit more aggressively which may lead to nipping of corals, aggression towards other fish, or all around bad behavior.