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Using Carbon filtration and Rowaphos for phosp

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Have been battling some algae problems and been reading on the issue. Have a few questions regarding the processes.

1a. Does carbon filtration reduces nitrates along with Ammonia?

1b. In the process, does it strip out other useful trace elements?

1c. Related to the above, should we stop carbon filtration when dosing?


Since I'm running a small sump, I've put in both carbon and rowphos in a the same fluidiser with the carbon at the bottom and rowphos just sitting on top of it.

2a. Will it cancel out each others' properties?

2b. Is it recommended to run it such that the largest amount of volume goes through it and hopefully maximise the time-effect or toggle down to the lowest flow so it provides sufficient time for the reaction to take place?


Have been using a skimmer and also tried chaetos to absorb more of the nitrates but algae problem still persists. Have also reduced the period of light being turned on in the display tank.


Thanks in advance.


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Firstly not all carbon is created equal, so look for low ash levels and harness as indicator of quality...

1a Carbon will remove the free floating organics in the water. As the organics break down they produce ammonia which goes on to produce nitrite and nitrate. So the carbon basically attacks the source of any issues before they occur. By removing the organics you will see an improvement in your water quality, which also means more effective PAR.

1b. Yes it will take trace elements and minerals out of the tank. In fact excessive usage of carbon has been linked to Head and lateral line disease. This can be avoided by using a trace element additive. The trend in reefing appears to only use carbon sparingly as opposed 24/7. But there is still an active debate on this.

1c That is a good question! Yes you don't want to directly run your dosing into a chamber which has or is preceeded by carbon. However if you dose into the tank directly or have by passed the carbon it is unlikely that the carbon is extracting at the same rate as it is being dosed. Consistency is key, so as you are measuring your tanks uptake of elements, remember that this already takes into account the fact you have carbon in place.

Do note that carbon will absorb various elements (gelbstoff, organics, medications, chlorine, pollutants, toxins, minerals and some trace elements). But it will exhaust eventually. So you should replace it roughly every 2 to 4 weeks.... small amounts replaced regularily is best practice, as if you replace all the carbon at the same time, you could impact the biological filtration capabilities of the tank, as carbon is a good bio-filter.

2a. This is common. However, you need to remember that the carbon will exhaust out before the phosphate remover. No big deal. Another consideration is that you don't want to tumble the carbon. This will cause dust which is not optimal as it coats your corals. So make sure it is packed down.

2b Depending on the grade and type of carbon there is a recommended flow rate. To keep it simple carbon is best run at low flow rate. Roughly 500 to 800lts/hr.

You mentioned still having algea issues. Maybe check the brand of carbon you use. Some low grade carbon will leach phosphate, and an accumulation of phosphate can lead to algea issues.

I hope this helps. Good luck

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