Originally Posted by Bblinks (Post 748507)

I run my carbon at a slow flow, just enough for a small tumble at the surface of the media and for phosphate I run it with high flow.

Originally Posted by gregzz4 (Post 748528)

Hmm ... maybe we could get some clarity here
I don't want to start an arguement :smile: but I've seen the opposite recommended

In the quote below ( taken from this thread ), Doug says higher flow for carbon, and lower flow for gfo


I've been running my carbon at a 'high boil' and my gfo at a more conservative 'rumble'

Greg, I think you should slow down on your "boiling" carbon, Carbon is activated by burning out the organic matter that was once in the vast series of pores which is extremely porus down to the molecular level. Think about when you are tumbling it at a boiling rate, it will not only pulverize the carbon into fine powder form it and leach some organic waste back into the water. There is a good article here about the usage of carbon. Also if you run carbon 24/7 on the tank some say it might absorb a lot of the trace elements which might cause HLLE, all you have to do is to add some trace back into the water.

I've read 'boiling' carbon can allow particles to enter the DT and cause HLLE, so my carbon exits before my socks ...

What's the correct flow rates ?
I don't think there is a correct answer for that question. It all depends on how you use the carbon, what kind of carbon you use, reactor or passive and wether its 24/7 or few hours a day or once a month. It all plays a important role. I run my 24/7 so a slow tumble at the surface works for me. Now I don't have a solidified number for the flow rate but I am guessing around 150-175gph.

Edit: To answer your question;
It's up to you. I run both of mine 24/7 but you could run them only when you need them