Dropping nutrients while dosing phophates?

[Reginald Reefer III]

One thing to note - CAC will reduce trace element concentrations in your tank, but not nearly as quickly as traditional carbon. Unless you are dosing trace and understand that demand, it may be best to try to only run that for a period of time and stop or run the risk of completely depleting things like manganese, iron, etc.

 

[Randy Holmes-Farley Verified Community Expert]

One thing to note - CAC will reduce trace element concentrations in your tank, but not nearly as quickly as traditional carbon.

What is the evidence for that?

 

[Reginald Reefer III]

https://www.researchgate.net/public...nicipal_process_of_surface_water_purification
The assumption I'm using is that the CAC will directly go after the dissolved organics/free radicals that are easily redox'ed in the water via it's surface structure and the traditional GAC without the modified surface structure will not as quickly absorb organics. Both will absorb trace elements and accomplish the same thing, just at different rates.

Lots of indirect studies on CAC vs GAC in waste water treatment and I'm using some correlations to come to that conclusion.

 

[Randy Holmes-Farley Verified Community Expert]

I don't doubt there are organic binding differences. I'm just skeptical that one can draw a conclusion on trace element binding levels.

 

[fish_collector]

FWIW, I used to spend hours and hours chasing the perfect numbers in my 80g SPS frag system. I tried to keep the nutrients lower by changing water, feeding less, siphoning out detritus etc but the corals just did not do well. After a year of this I began to get a bit lazy and I let the tank just run on its own. I only change 10g of water every 2-3 weeks, I never siphon detritus, I never even empty the skimmer cup. I feed the fish as much as they want to eat for as long as they want to eat. The results speak for themselves, the corals have never looked better and are growing faster than ever, and I have very little algae. I hadn’t checked nutrients in a long time so I decided to see where they were, and were higher than I had anticipated but I’m leaving them as is. Moral of my story is let your tank do what it wants to do and see what your corals look like. Chasing specific numbers becomes madness and never accomplishes anything. Randy is spot on with his nutrient recommendations.

 

[CHSUB]

My nitrates stay around 30ppm

I would definitely look to lower. My most successful aquariums have always had nearly undetectable no3.

I do not see much about your aquarium? I would start by wet skimming, using GAC, cleaning daily or using filter socks, limit over feed, while doing WC concentrate on detritus and algae removal. If after a month of increased wc % and “better” maintenance, if no significant results try vinegar dosing. I would not use any po4 reduction media.

 

[jordanrb]

FWIW, I used to spend hours and hours chasing the perfect numbers in my 80g SPS frag system. I tried to keep the nutrients lower by changing water, feeding less, siphoning out detritus etc but the corals just did not do well. After a year of this I began to get a bit lazy and I let the tank just run on its own. I only change 10g of water every 2-3 weeks, I never siphon detritus, I never even empty the skimmer cup. I feed the fish as much as they want to eat for as long as they want to eat. The results speak for themselves, the corals have never looked better and are growing faster than ever, and I have very little algae. I hadn’t checked nutrients in a long time so I decided to see where they were, and were higher than I had anticipated but I’m leaving them as is. Moral of my story is let your tank do what it wants to do and see what your corals look like. Chasing specific numbers becomes madness and never accomplishes anything. Randy is spot on with his nutrient recommendations.

I'm not sure if leaving it will work. My sps are really suffering.

I'm hoping the icp test shows the issue because as of now the only thing that doesnt look "great" are my nutrients.

 

[jordanrb]

I would definitely look to lower. My most successful aquariums have always had nearly undetectable no3.

I do not see much about your aquarium? I would start by wet skimming, using GAC, cleaning daily or using filter socks, limit over feed, while doing WC concentrate on detritus and algae removal. If after a month of increased wc % and “better” maintenance, if no significant results try vinegar dosing. I would not use any po4 reduction media.

It's a redsea 20g cube. I've been doing more wet skimming but have only seen a very tiny drop in nitrates. I use 250 sock and clean every few days, filter floss, sponge and carbon sac. 20% weekly wc.

 

[fish_collector]

I'm not sure if leaving it will work. My sps are really suffering.

I'm hoping the icp test shows the issue because as of now the only thing that doesnt look "great" are my nutrients.

You’re really not likely to find the culprit with an ICP test. Is it possible you have a rusty magnet somewhere? Have you messed with lighting and flow? Is your make up water produced with a high rejection membrane? And does your alk remain stable with no fluctuation? Just some other things to think about.

Lowering your nutrients with corals that are doing poorly already will usually do no good.

 

[CHSUB]

It's a redsea 20g cube. I've been doing more wet skimming but have only seen a very tiny drop in nitrates. I use 250 sock and clean every few days, filter floss, sponge and carbon sac. 20% weekly wc.

How many fish and how are you feeding? I believe hobbyists are not placing enough rock or have a lot of dead spots with flow? You stated two wave makers so likely not the issue. Are you turkey basting your rock during WC and vacuuming detritus, this is often overlooked? Just removing water without detritus is not as effective.

 

[jordanrb]

You’re really not likely to find the culprit with an ICP test. Is it possible you have a rusty magnet somewhere? Have you messed with lighting and flow? Is your make up water produced with a high rejection membrane? And does your alk remain stable with no fluctuation? Just some other things to think about.

Lowering your nutrients with corals that are doing poorly already will usually do no good.

Definitely nothing rusting in the tank. Lighting and flow has been the same for months. I purchase rodi and pre mixed salt water. Alkalinity goes from 8-8.4 maximum over a week.

 

[fish_collector]

Definitely nothing rusting in the tank. Lighting and flow has been the same for months. I purchase rodi and pre mixed salt water. Alkalinity goes from 8-8.4 maximum over a week.

Perhaps your water is not as pure as it needs to be? I saw a difference in my tanks when I install a new membrane in my rodi. I was using a membrane that I thought was a Filmtek but ended up it wasn't, so after I started using the real deal I saw an improvement in coralhealth in general, as well as a decline of certain types of problematic algaes.

Can you at least verify that the rodi you get has zero tds? There is a lot more than tds that could be in your water though, which is why I previously asked if you used high rejection membranes to process your water. TDS is easy to measure, the other things that could be in your water are not so easy to detect.

Seems like it's been recommended already, but do you regularly use carbon in your tank? They are not all equal lol. I have had good luck with coconut carbon as well as Rox 0.8. Stay away from carbon derived from coal (lignite) as it has been demonstrated to be a cause of HLLE. I try to change my carbon at least once a month but it never works out that way, sometimes I let it go for so long the output from the cannister it's in becomes just a trickle lol. I've seen no negative effects from using it 24/7.

But as I've stated, I personally wouldn't try to reduce your nutrients, I don't feel they're elevated enough to affect coral health. In a perfect world I'd keep mine at 5 and 0.08 but that is nearly impossible to do and keep it there. It's the movement of parameters that corals struggle with, even something as innocent as a 25-50% water change can set corals back. I couldn't say when the last time I changed that much water, it's usually 10% or so. If there is more siphon work that needs to be done after I've took out 10 gallons, I just leave it there for the next time I change water.

I also use a filter sock, I think the junk it removes outweighs the benefits of leaving it lol. My tank is a frag tank, and I've got 100% of my rock in the middle section of my sump. If I run the tank with no filter sock the rock section gets so dirtied up with detritus that it's inevitable some of the organics would get converted to nitrate, so I filter it out. There's still a ton of life in the rock even with filter sock use. And I will admit that the sock overflows before I change it out most of the time haha.

I hope I've helped you some, I'm not an expert but I've been doing this long enough that I have a good idea of what works and what doesn't.