Can carbon dosing lead to nitrate spike with undersized skimmer?

[xCry0x]

Question:

My skimmer is an Aquamaxx hob-1, rated at 50-75g. Can an undersized skimmer lead to carbon dosing causing an increase in nitrates?

History:

My tank is ~4 years old; a lot of the rock and coral were moved from a prior system dating back ~6 years. It is a RSM 250 -- so ~60g capacity AIO tank.

I'v had more issues with this newer larger system that I ever had with my original nano that I basically more or less completely neglected any type of regular maintenance on.

In an effort to combat red turf that took over the tank, I decided to start pulling the sand bed out and dosing carbon.

My nitrates and phosphates never tested particularly high before. But I assumed they existed since the algae kept growing.

Current:

I pulled the bulk of the sand out of the tank over the past ~6 months. I'v been dosing vinegar through my dosing pump at 20ml/day 2x day.

My nitrates and phosphates have never been higher - the nitrates on salifert test are testing in the 50-100 range -- dark-ish pink. Phosphates testing at 0.2 ppm where they have historically always been sub 0.04 on hannah ULR test.

I have minimal green algae growth on my tank glass. But I'v been having a lot of my long term LPS corals dye off -- 2 large chalices, an acan I'v had for 6 years, my 3rd ~10" chalice is in the process of dying. Coralline algae growth has come to a complete halt as well.

The lack of green algae growth and LPS death would make me think my tank was horribly nutrient starved - but the tests are coming back ever than I have ever had on any of my tanks.

Additional:

My fish stocking:

• 2x true perc clowns
• Flame angel
• Midas blenny
• blue star leopard wrasse
• YWG
• Pygmy hawkfish
• 1x banggai cardinal

For years I struggled with what I thought was the opposite problem - my nitrates were always 0. I thought that was the cause of poor coral growth so I started fiddling with that 2 years ago, dosed nitrates for a short period, then added the 2 clowns + pygmy hawk fish which seemed to lead to an increase in detectable nitrates.

I feed 1 cube frozen mysis a day and usually a pinch of flake.

==

Thanks for reading - any thoughts/feedback appreciated.

 

[Dan_P]

Question:

My skimmer is an Aquamaxx hob-1, rated at 50-75g. Can an undersized skimmer lead to carbon dosing causing an increase in nitrates?

I don’t immediately see how a nitrate level would increase with carbon dosing, even with no skimmer.

So, let’s kick this thread off with an unequivocal “NO” way.

I will now go back and develop a few thoughts about your nitrate level.

 

[Dan_P]

Question:

My skimmer is an Aquamaxx hob-1, rated at 50-75g. Can an undersized skimmer lead to carbon dosing causing an increase in nitrates?

History:

My tank is ~4 years old; a lot of the rock and coral were moved from a prior system dating back ~6 years. It is a RSM 250 -- so ~60g capacity AIO tank.

I'v had more issues with this newer larger system that I ever had with my original nano that I basically more or less completely neglected any type of regular maintenance on.

In an effort to combat red turf that took over the tank, I decided to start pulling the sand bed out and dosing carbon.

My nitrates and phosphates never tested particularly high before. But I assumed they existed since the algae kept growing.

Current:

I pulled the bulk of the sand out of the tank over the past ~6 months. I'v been dosing vinegar through my dosing pump at 20ml/day 2x day.

My nitrates and phosphates have never been higher - the nitrates on salifert test are testing in the 50-100 range -- dark-ish pink. Phosphates testing at 0.2 ppm where they have historically always been sub 0.04 on hannah ULR test.

I have minimal green algae growth on my tank glass. But I'v been having a lot of my long term LPS corals dye off -- 2 large chalices, an acan I'v had for 6 years, my 3rd ~10" chalice is in the process of dying. Coralline algae growth has come to a complete halt as well.

The lack of green algae growth and LPS death would make me think my tank was horribly nutrient starved - but the tests are coming back ever than I have ever had on any of my tanks.

Additional:

My fish stocking:

• 2x true perc clowns
• Flame angel
• Midas blenny
• blue star leopard wrasse
• YWG
• Pygmy hawkfish
• 1x banggai cardinal

For years I struggled with what I thought was the opposite problem - my nitrates were always 0. I thought that was the cause of poor coral growth so I started fiddling with that 2 years ago, dosed nitrates for a short period, then added the 2 clowns + pygmy hawk fish which seemed to lead to an increase in detectable nitrates.

I feed 1 cube frozen mysis a day and usually a pinch of flake.

==

Thanks for reading - any thoughts/feedback appreciated.

Let’s get @brandon429 ideas on what might happen when you remove an old sand bed.

I presume by removing the sand bed you lost all or most of the denitrification capability in your system but not the system’s nitrification capabilities. Not sure what else happened to the system’s waste removal capabilities that might be disturbing the coral. Maybe the vinegar or bacteria growth from the vinegar dosing is bothering the coral. I would consider a large water change, though wait for a few more ideas.

 

[xCry0x]

If there isn't a logical reason for the dosing to raise nitrates then that is great - means I should be able to hold course until I see nitrates get under control.

Longer story here is that I started tinkering w/ one of Brandon's algae killing threads.

Nothing was working so I decided to try a vibrant dose since it had worked in the past with bubble algae. Was going to go less aggressive - long term dose and see what happened over the course of 2-3 months.

Well, normal results; algae on glass went away. Red turf seemed to receed slightly and generally stop growing. Nitrates spiked from trace detectable to current state. So I started to carbon dose since I read that can be helpful in conjunction with vibrant to remove the nitrates that show up when the algae stops consuming them.

Then the LPS started to die -- which is what happened the first time I used vibrant as well. So I cut out the vibrant but kept the vinegar dose.

This was ~2 months ago -- been dosing steady with vinegar, nothing else changing. LPS still dying, coralline not growing, minimal algae on glass, nitrate still high.

So I was concerned the vinegar dosing was having some issue - wondered if it was skimmer related.

And fyi - the sand bed removal was ~ 1/2 - 1 cup at a time with water changes over the course of the past 6 months. Specifically took it super slow as to not cause a nitrate spike simply due to removing denitrifying bacteria in mass from the sand bed.

Also to be clear, this isn't a knock on Vibrant. Was intentionally doing a 2x a week dose at 1ml/10 gallon tank water because that was the only thing that worked for me when knocking out bubble algae a few years ago. Their "dirty" dose would be 1x a week and maintenance is every other week.