I am designing a sump system for my marine aquarium and and up to the stage of calulcating flow rates etc.

My question was quite generic - does there have to be a specific amount of water flowing down to the sump and back up to the main tank? (x lph)

The reason I ask because I was thinking about live rock that I have in the main tank. There needs to be around 30x circulation to be a decent reef system for my tank size.


Is there a similar kind of principle for water in/out of the sump tank? All I will have is the skimmer, live sand, heater, return pump down there.

May be a silly question, but does the sand etc need a circulation rate like in the main tank?

If you have a deep sand bed for removing nitrates then you want a slow flow rate across it, no more than about 5x per hour. If you have the sump full of Caulerpa and other macro algae then again a 5x per hour flow rate through it. This gives the algae more time to absorb the nutrients.
Most people have extra pumps in the main tank to circulate water around the live rock and get the flow rate up to 30x or more.

what he said, you want it to be fast, but slow enough for the filters (plants, sand, skimmer etc) to do their job.

Kinda hypocritical since im running like 950gph in a 65 gallon tank through the sump....

This post has been edited by Musho3210: Jul 7 2008, 12:45 AM