High phosphate, low nitrate - time for GFO?

[ReefinIt]

I have been dealing with high phosphates ever since I set my 120g mixed reef, about 1.5 years. It started at 0.9 mg/l, now it’s around 0.16. Nitrates have barely been detectable. Highest level was 0.8 mg/l. Measurements taken by Hanna ULR phosphate and HR nitrate. ICP also confirmed the high phosphate, undetectable nitrate.

I used old live rock (Fiji, pukani, tonga, etc.) from past tanks that has been sitting outside for years. I bleached the rock, then did an acid bath. I hoped the acid wash would knock down some phosphates, but doesn’t look like it. Rocks dropped in size so the acid did take off some layers.

For nutrient export, I have a skimmer, mesh socks, and chaeto. Plus water changes 3x per month ranging from 10-20%.

Lightly stocked with fish, semi stocked on corals but not fully grown in. Everything is generally healthy.

I have been dealing with a persistent hair algae/turf algae problem that I want to get resolved.

I tried dosing small amounts of nitrate. Thought that maybe nitrate is the limiting factor, so if I increase it, phosphate could drop. Also because it was so low. Might have slightly worked, but algae also grew.

I’m wondering if there is just ton of phosphate bound in the rock and I’m fighting a never ending battle.

Is GFO worth trying in this scenario? I’ve been very hesitant on trying it. Don’t want to kill my system. Should I use a reactor if I do it?

Is there another option?

 

[Reefer_kano]

I was having some what the same issue.
High phos, low nitrate.

I increased the intensity of my refugium light which help a bit but I eventually started using a bit of rowaphos.

When using rowa, definitely start slow and test frequently, you don't want to strip your tank out quickly.

Yes, you can pick up a small reactor for it for about 50 bucks

 

[Reefer_kano]

You can also use some neonitro (nitrate dosing to help you elevate nitrates.

 

[ReefinIt]

I was having some what the same issue.
High phos, low nitrate.

I increased the intensity of my refugium light which help a bit but I eventually started using a bit of rowaphos.

When using rowa, definitely start slow and test frequently, you don't want to strip your tank out quickly.

Yes, you can pick up a small reactor for it for about 50 bucks

Yeah, I also increased my refugium light intensity. Also tried dosing nitrate.

Never heard of rowaphos. I’ll look into it. Thanks!

 

[Uncle99]

Iam confused (that’s sometimes easy)
Your phosphate was .9 (very high) and now .16 which seems perfect to me. Do I read that right?

I agree that Nitrate low, bump to 5-10ppm.

 

[Lavey29]

Agree, phosphate at .16 is fine. How does your tank look? You can always place a bag of phosguard in your sump to walk the phosphate down slowly if you want. Nitrates need to be at 10.

 

[exnisstech]

If it were me I would just dose some nitrate and leave PO4 alone for now. I have a tank that runs PO4 0.4 - 0.6 and the tank is thriving but my NO3 is mid teens. Both tested using Hanna testers. Nice thing about dosing nitrate is you can go fast. I raise mine 5ppm at a time when it's zeroed out.

 

[Koty]

Your phosphate is fine. Iwhould dose carbon and amino acids and not nitrate.

 

[Pistondog]

I have been dealing with high phosphates ever since I set my 120g mixed reef, about 1.5 years. It started at 0.9 mg/l, now it’s around 0.16. Nitrates have barely been detectable. Highest level was 0.8 mg/l. Measurements taken by Hanna ULR phosphate and HR nitrate. ICP also confirmed the high phosphate, undetectable nitrate.

I used old live rock (Fiji, pukani, tonga, etc.) from past tanks that has been sitting outside for years. I bleached the rock, then did an acid bath. I hoped the acid wash would knock down some phosphates, but doesn’t look like it. Rocks dropped in size so the acid did take off some layers.

For nutrient export, I have a skimmer, mesh socks, and chaeto. Plus water changes 3x per month ranging from 10-20%.

Lightly stocked with fish, semi stocked on corals but not fully grown in. Everything is generally healthy.

I have been dealing with a persistent hair algae/turf algae problem that I want to get resolved.

I tried dosing small amounts of nitrate. Thought that maybe nitrate is the limiting factor, so if I increase it, phosphate could drop. Also because it was so low. Might have slightly worked, but algae also grew.

I’m wondering if there is just ton of phosphate bound in the rock and I’m fighting a never ending battle.

Is GFO worth trying in this scenario? I’ve been very hesitant on trying it. Don’t want to kill my system. Should I use a reactor if I do it?

Is there another option?

How did you get from 0.9 to 0.16?
Sounds like things are fine.
Read about fluconanzole if you want to nuke the gha.

 

[bobnicaragua]

My tank also tends to run high phosphate and lower nitrate. I mix GFO and carbon in a filter bag and throw it between the baffles in the sump.

 

[EeyoreIsMySpiritAnimal]

Duplicate

 

[EeyoreIsMySpiritAnimal]

Your phosphate is fine. Iwhould dose carbon and amino acids and not nitrate.

Why dose carbon when that's likely to lower nitrates even further?

 

[jda]

.16 ppm of po4 might not be OK for some of the things that you want to keep, but also could be totally fine for others. If you want to lower it, then GFO is a solid plan. You can use Lanthanum Chloride too. Both take care not to lower too quickly.

It it also totally a good plan not to let it get too much higher.

Study up on Lantanum Chloride dosing. If you need any help with LC or GFO, just hollar. Both work fine in small, frequent doses so that po4 does not spike down too far and then spike back up after the aragonite unbind po4.

Do not worry about the nitrate. If your stuff is growing and doing well, then you are not nitrogen limited and the corals can get nitrogen from other things like ammonia or nitrite.

 

[ReefinIt]

Agree, phosphate at .16 is fine. How does your tank look? You can always place a bag of phosguard in your sump to walk thephosphate down slowly if you want. Nitrates need to be at 10.

Been dealing with a persistent hair algae problem so I was hoping if I knock down the P it might help. I have been scrubbing the rocks weekly/biweekly. Feed sparingly. Have herbivores. Nothing seems to be working.

Corals generally seem fine. Some of the SPS don't don't have the best color.

How did you get from 0.9 to 0.16?
Sounds like things are fine.
Read about fluconanzole if you want to nuke the gha.

Feeding sparingly, exporting through removal of algae/chaeto, skimming. Also dosed small amounts of N. I thought Fluconanzole was for bryopsis. I try to avoid adding things to my take unless necessary.

My tank also tends to run high phosphate and lower nitrate. I mix GFO and carbon in a filter bag and throw it between the baffles in the sump.

That's what I was wondering. If I could just throw in a bag between the baffles vs get a reactor.

.16 ppm of po4 might not be OK for some of the things that you want to keep, but also could be totally fine for others. If you want to lower it, then GFO is a solid plan. You can use Lanthanum Chloride too. Both take care not to lower too quickly.

It it also totally a good plan not to let it get too much higher.

Study up on Lantanum Chloride dosing. If you need any help with LC or GFO, just hollar. Both work fine in small, frequent doses so that po4 does not spike down too far and then spike back up after the aragonite unbind po4.

Do not worry about the nitrate. If your stuff is growing and doing well, then you are not nitrogen limited and the corals can get nitrogen from other things like ammonia or nitrite.

Yeah, I was doing very low dosing of N but cautious about it.

 

[Lavey29]

Been dealing with a persistent hair algae problem so I was hoping if I knock down the P it might help. I have been scrubbing the rocks weekly/biweekly. Feed sparingly. Have herbivores. Nothing seems to be working.

Corals generally seem fine. Some of the SPS don't don't have the best color.


Feeding sparingly, exporting through removal of algae/chaeto, skimming. Also dosed small amounts of N. I thought Fluconanzole was for bryopsis. I try to avoid adding things to my take unless necessary.


That's what I was wondering. If I could just throw in a bag between the baffles vs get a reactor.



Yeah, I was doing very low dosing of N but cautious about it.

You got a diverse cleaner crew including turbos and urchins?

 

[ReefinIt]

You got a diverse cleaner crew including turbos and urchins?

Have turbos but no urchins. Don’t want to deal with them moving things around. Some rock I have is basically a dead coral skeleton and it would be hard for anything to get in the cracks to eat it.

 

[Lavey29]

Have turbos but no urchins. Don’t want to deal with them moving things around. Some rock I have is basically a dead coral skeleton and it would be hard for anything to get in the cracks to eat it.

Tuxedo urchins don't move anything significant. They might have a snail shell or zoa polyp on them but that's pretty much it and they mow down GHA. My tank is wall to wall corals and the tuxedos never bother anything.

 

[Pistondog]

Feeding sparingly, exporting through removal of algae/chaeto, skimming. Also dosed small amounts of N. I thought Fluconanzole was for bryopsis. I try to avoid adding things to my take unless necessary.

reduces gha also.
Difficult to manage gha with nutrient reduction, they evolved in low nutrient environs.

 

[Brian1f1]

Have turbos but no urchins. Don’t want to deal with them moving things around. Some rock I have is basically a dead coral skeleton and it would be hard for anything to get in the cracks to eat it.

Urchins are worth the trouble imo.

 

[jda]

Rock and pencil urchins do not disturb much either - if they did, then you did not secure them well. Just avoid pincushions and most long spine and your corals will stay put. The rock and pencils tend to want to stay on the rocks, for me. The other kinds just want to graze easy algae on the glass.

The urchins get the mass stuff and then the crabs and snails get into the nooks and crannies. Emerald and blue legs are good algae eaters, but they cannot eat a ton, so something has to do the heavy work and let them clean up.

Here is a mini chalice colony that grew algae around the base in my fuge. I put it into the display and in about 2 hours, the crabs and some ceriths cleaned up most of the hairy algae with all gone overnight. At one point, there was probably a dozen shells on there.

Before:

After: