Should I remove my RDSB?

[RobertK]

I have a 70 gallon reef tank with a 4-5" DSB that has been in place for many years, as well as a remote 10 gallon chaetomorpha refugium with a 7" DSB. These were set up years ago, back when I thought a ULNS was ideal. NO3 and PO4 were both reading zero. I was also dosing vinegar but stopped that a couple months ago. I've been trying to get N and P levels up into Hanna-detectable ranges with increased feedings. Phosphate levels came up to 0.3-0.35 with those changes. Nitrate came up to 3-5 but has since dropped back down to zero. I can't remove the DSB from the display but I'm wondering if removing the RDSB in the refugium might help prevent NO3 levels from zeroing (but doing so would also increase the volume available for chaetomorpha growth). The other option would be to leave things as is and begin dosing N. I'm looking for the simplest long-term solution. Any advice would be welcome. Thanks.

 

[Reefer Matt]

It’d be easier to pinpoint a specific range of nutrients by dosing if you are trying to maintain a tight band. However if you don’t have sensitive species, removing some sand from the fuge could help. But I’d do it a little at a time over a period of a few months to be safe.

 

[RobertK]

It’d be easier to pinpoint a specific range of nutrients by dosing if you are trying to maintain a tight band. However if you don’t have sensitive species, removing some sand from the fuge could help. But I’d do it a little at a time over a period of a few months to be safe.

Thanks Matt. I am chasing numbers a bit at present. I am trying to dial in my nutrient levels after a long period of neglect. I'm hoping that will allow me to keep some corals that I've not had success with in the past. I might try increasing feedings further, but that seems to be driving P up higher than N. I like your idea of removing the sand a little at a time, as long as I don't hit any H2S pockets.

 

[Randy Holmes-Farley Verified Community Expert]

I would not assume the dsb is doing anything, but it’s hard to know.

 

[RobertK]

I would not assume the dsb is doing anything, but it’s hard to know.

If I remove the DSB that will double the volume available for chaetomorpha growth. What effect might that have on NO3 and PO4 levels in the attached display tank?

 

[gbroadbridge]

I have a 70 gallon reef tank with a 4-5" DSB that has been in place for many years, as well as a remote 10 gallon chaetomorpha refugium with a 7" DSB. These were set up years ago, back when I thought a ULNS was ideal. NO3 and PO4 were both reading zero. I was also dosing vinegar but stopped that a couple months ago. I've been trying to get N and P levels up into Hanna-detectable ranges with increased feedings. Phosphate levels came up to 0.3-0.35 with those changes. Nitrate came up to 3-5 but has since dropped back down to zero. I can't remove the DSB from the display but I'm wondering if removing the RDSB in the refugium might help prevent NO3 levels from zeroing (but doing so would also increase the volume available for chaetomorpha growth). The other option would be to leave things as is and begin dosing N. I'm looking for the simplest long-term solution. Any advice would be welcome. Thanks.

Before you do anything I would ask what problems are you seeing?

I don't see change for the sake of change as a plan.

If it's working why change anything?

 

[Randy Holmes-Farley Verified Community Expert]

If I remove the DSB that will double the volume available for chaetomorpha growth. What effect might that have on NO3 and PO4 levels in the attached display tank?

If done properly, I would expect that growing macroalgae will reduce phosphate more than the dsb, which won’t do much for phosphate. It may well remove N faster too.

 

[RobertK]

If done properly, I would expect that growing macroalgae will reduce phosphate more than the dsb, which won’t do much for phosphate. It may well remove N faster too.

Thanks Randy! Do you agree with Matt that it is a good idea to remove it slowly rather than all at once?

Before you do anything I would ask what problems are you seeing?

I don't see change for the sake of change as a plan.

If it's working why change anything?

I described my current situation in post #7 of my tank thread, but I'll summarize it for you.

For the last decade or more I did everything I could to keep NO3 and PO4 levels at zero based on the predominant thinking in the hobby from 20 years ago. I fell out of touch with advances in the hobby but managed to keep my tank going, however there were a lot of corals I could not keep alive. It is only recently that I've caught up with current thinking about nutrient requirements. I am trying to get NO3 and PO4 levels stabilized in the ranges that Randy recommends. I want to see if that allows me to keep some of the corals I've not had success with in the past. I thought I was there but now NO3 has dropped back down to zero again. I did have a minor cyano outbreak while making these recent adjustments, but that seems to have largely resolved at this point.

 

[gbroadbridge]

I described my current situation in post #7 of my tank thread, but I'll summarize it for you.

For the last decade or more I did everything I could to keep NO3 and PO4 levels at zero based on the predominant thinking in the hobby from 20 years ago. I fell out of touch with advances in the hobby but managed to keep my tank going, however there were a lot of corals I could not keep alive. It is only recently that I've caught up with current thinking about nutrient requirements. I am trying to get NO3 and PO4 levels stabilized in the ranges that Randy recommends. I want to see if that allows me to keep some of the corals I've not had success with in the past. I thought I was there but now NO3 has dropped back down to zero again. I did have a minor cyano outbreak while making these recent adjustments, but that seems to have largely resolved at this point.

Thanks, but I had read the whole thread.

Sounds like you have a successful tank which has simply had problems with some coral. No problems with nuisance dinoflagellates or any other real nuisance.

Everyone has problems with some types of coral, mainly as most coral we try to keep together do not exist together in nature.

So you're hopeful that a drastic change may make that possible.

I would suggest that the grass is not always greener, and in the absence of any real issues you may well be best advised to not make drastic changes which could potentially destabilise your system with the resulting avalanche of negative effects.

Of course maybe you want a challenge, but I try to avoid change just for the sake of change. If it ain't broken, etc.

Been though a nightmare of my own creation once, never again.

 

[RobertK]

Thanks for that, point well taken. As I said I'm looking to stabilize my nutrient levels, certainly not looking to destabilize my system. Just wondering if this old RDSB is still worth keeping. If it is doing what it was purported to do (reduce nitrates) then it might be doing too good of a job.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks Randy! Do you agree with Matt that it is a good idea to remove it slowly rather than all at once?



I described my current situation in post #7 of my tank thread, but I'll summarize it for you.

For the last decade or more I did everything I could to keep NO3 and PO4 levels at zero based on the predominant thinking in the hobby from 20 years ago. I fell out of touch with advances in the hobby but managed to keep my tank going, however there were a lot of corals I could not keep alive. It is only recently that I've caught up with current thinking about nutrient requirements. I am trying to get NO3 and PO4 levels stabilized in the ranges that Randy recommends. I want to see if that allows me to keep some of the corals I've not had success with in the past. I thought I was there but now NO3 has dropped back down to zero again. I did have a minor cyano outbreak while making these recent adjustments, but that seems to have largely resolved at this point.

I personally would not try to remove a dsb slowly. Too difficult to keep the remaining part working, if it is doing anything at all. I’d disconnect it, remove all the sand, rinse, and reconnect.