Im having trouble grasping flow within tank.

[Chrisnugent942]

So I have a 40g breeder with two koralia

240gph and a fluval 407 (brought the pump down to half so it doesnt blow sand) output pushing water down the middle. Ive been thinking about this all day.

does my tank have enough surface agitation for oxygenexchange?

Is the flow two much for my two clowns?

How should I point them? One on the left is pointing behind the rocks for dead spots and one on the right point up for surface agitation and towards the middle.

And when it’s recommended to having enough flow for no dead spots does that mean when I feed the food pellets shouldnt make it to the sand and if they do manage to sink to the bottom would that be
considered adead spot?

Id really appreciate any insight.

 

[Ron Reefman]

Based on the video, you have plenty of surface agitation. It really doesn't take much. It more about getting the surface water moving.

I'd worry less about dead spots and more about random flow. Are you familiar with how you rate the total flow in your tank?

Total gph flow of all your pumps including the return from the sump, divided by the total number of gallons in just the DT. So total flow of 2000gph divided by 100 gallon tank equals 20 'turns' per hour. Most reefer shoot for something in the 30 to 50 turns per hour. Zoas and soft corals need less, sps corals like more.

 

[ReefStable Verified Sponsor]

Dead spots are where you will see food and waste settle on the bottom. I have an article discussing flow for reef tanks here if you're interested. Overall, if you're looking for SPS coral, you will need much more flow than soft corals.

Making sure to get turbulence in the flow is also very important (as noted in the article).