Anyone Dosing Carbon?

[RYcube2951]

Water changes are good for nitrate reduction, but not so good for phosphate. Even a 100% change will not eliminate it as there is a lot bound to rock and sand that will come off after the drop from a water change.

So how do people obtain low readings?

 

[Randy Holmes-Farley Verified Community Expert]

So how do people obtain low readings?

Continuous removal, such as with a binder (GFO, aluminum oxide, lanthanum, etc.) or with macroalgae. You still have to remove some of the PO4--- from the sand that way, but unlike a water change, it isn't a one-try process. .

 

[RYcube2951]

I have carbon dosed about everything you can. I used to run my skimmer 24/7. I started turning it off for 3-4 hours at night to give bacteria a chance to multiply. My experience has been that doing this has been just like carbon dosing but without the danger of overdosing. My tank settled in with nitrates around 20 and phosphates .08-.1. The last remaining stubborn algae disappeared after 3-4 weeks. And the corals took off. Interesting thing is that my skimmer became more productive and mulm appeared on my mechanical filtration just like when I carbon dose.

If you do decide to carbon dose start at 25% to 30% of the recommended dosing. You actually need so little that I found the challenge was diluting for automatic dosing. Before I learned the skimmer trick, I was dosing drops with a pipette daily.

So was it carbon dosing along with turning the skimmer off that lowered your nutrients? Or, was it stopping dosing carbon and just turning your skimmer off?

 

[GainesvilleReef]

So was it carbon dosing along with turning the skimmer off that lowered your nutrients? Or, was it stopping dosing carbon and just turning your skimmer off?

I stopped carbon dosing when I started turning the skimmer off.

There is an explanation about how this works about 10 minutes into the video.

Fighting algae by turning skimmer off

 

[RYcube2951]

Sorry but I'm still confused. Have you permanently stopped dosing carbon? Are you just turning your skimmer off for a few hours to lower nutrients? I have a bottle of Brightwell Reef Biofuel that says you can keep the skimmer on or have it off for a few hours for better assimilation. But, I didn't know you could lower nutrients by just turning off the skimmer periodically. Maybe I'm misinterpreting your message.

 

[Doctorgori]

Sorry but I'm still confused. Have you permanently stopped dosing carbon? Are you just turning your skimmer off for a few hours to lower nutrients? I have a bottle of Brightwell Reef Biofuel that says you can keep the skimmer on or have it off for a few hours for better assimilation. But, I didn't know you could lower nutrients by just turning off the skimmer periodically. Maybe I'm misinterpreting your message.

shoot ... might be overthinking a lil...hey if. testing and dosing is a pain, you could indeed mindlessly put a bag if gfo in flow somewhere and monitor it a lil less, I’ve done that before too, but whatever, heck tank sounds fine as is...regards your on the right path

 

[GainesvilleReef]

Sorry but I'm still confused. Have you permanently stopped dosing carbon? Are you just turning your skimmer off for a few hours to lower nutrients? I have a bottle of Brightwell Reef Biofuel that says you can keep the skimmer on or have it off for a few hours for better assimilation. But, I didn't know you could lower nutrients by just turning off the skimmer periodically. Maybe I'm misinterpreting your message.

I have permanently stopped carbon dosing. Basically, the problem is that our skimmers are too efficient at removing bacteria. By shutting it down for a few hours it gives the bacteria time to multiply. Let's use 20 minutes as the doubling rate for heterotrophic bacteria. In 3 hours they would double 9 times. Or 512 times the bacteria you started with. Of course, this ignores other limiting factors such as available carbon, phosphate, and nitrogen. But it is the underlying principle. Since these bacteria are skimmed off eventually it results in lowering nutrients. So it reduces nutrients the same way as carbon dosing. Bacteria consume the nutrients and get skimmed out. Both methods reduce a different limiting factor in bacterial growth. Quite frankly I was surprised at how well it works. I found a post from Dr. Tim about 8 years ago where he says you can not over skim. And in the video, he is telling you to turn the skimmer off. Goes to show old reefers can learn new tricks. But also skimmers are a lot more efficient than they used to be.

 

[Randy Holmes-Farley Verified Community Expert]

I have permanently stopped carbon dosing. Basically, the problem is that our skimmers are too efficient at removing bacteria. By shutting it down for a few hours it gives the bacteria time to multiply. Let's use 20 minutes as the doubling rate for heterotrophic bacteria. In 3 hours they would double 9 times. Or 512 times the bacteria you started with. Of course, this ignores other limiting factors such as available carbon, phosphate, and nitrogen. But it is the underlying principle. Since these bacteria are skimmed off eventually it results in lowering nutrients. So it reduces nutrients the same way as carbon dosing. Bacteria consume the nutrients and get skimmed out. Both methods reduce a different limiting factor in bacterial growth. Quite frankly I was surprised at how well it works. I found a post from Dr. Tim about 8 years ago where he says you can not over skim. And in the video, he is telling you to turn the skimmer off. Goes to show old reefers can learn new tricks. But also skimmers are a lot more efficient than they used to be.

If excessively low nutrients are an issue, one can certainly consider reducing skimming (or other options).

However, I do prefer the option of stopping skimming due to aeration considerations. if I were to do it, I'd be sure to do it when O2 is naturally high (near mid to late light cycle).

 

[RYcube2951]

What is the best way for me to find out what type of algae or bacteria is on my black sand? My sand gets these brown colored patches. At least they look brown but the color is hard to tell because of the black sand. It looks like a film rather than hair.

 

[GainesvilleReef]

If excessively low nutrients are an issue, one can certainly consider reducing skimming (or other options).

However, I do prefer the option of stopping skimming due to aeration considerations. if I were to do it, I'd be sure to do it when O2 is naturally high (near mid to late light cycle).

That has always been a concern for me as well. And was one of the reasons I ran it 24/7. But I have not had any problems and I have lots of fish. I have variable speed skimmer pumps that I can control with my apex. I created an aeration only low-speed profile. I run aeration only for 3 hours from 9 pm -12 am, completely off from 3 am-6 am every night, and full skimming the rest of the day. I have also gone without a skimmer for more than a week while replacing a pump. No issues. Then there are all the tanks that run without skimmers. Julian Sprung did a tank just to prove it could be done without one. With all that said, I would always recommend skimmer if possible in a setup.

I also had the same thoughts as you about turning off in the evening, but instead of picking times when O2 would be high, I picked a time when I thought demand for O2 would be the lowest. After thinking about it again now. Another benefit of shutting the skimmer off in the evening might be increased bacterial growth due to more available O2. I may switch it around to give it a try.

And while I have your ear. I want to thank you for all of your efforts in this hobby. I am pretty sure I have read all of your articles. I would not have lasted the last 8 years without your help.