Too much current in 36 gal tank?

[jayjay5531]

Hey folks,

I got a 36 gallon bowfront tank from a friend with 5 blue-green chromises in it, about 3 inches of sand, and (by my estimation) 40-50 pounds of live rock. The only circulation was a Penn Plax Cascade 700 canister filter (which advertises 185 gph). I decided to get a protein skimmer - the CoralVue Reef Octopus 100 HOB (which advertises 92 gph) - and two power heads pointing somewhat towards each other from opposite sides of the tank - Tunze Turbelle NanoStream 6015 powerheads (which advertise 476 gph each).

I added both powerheads and the protein skimmer at the same time (maybe this was a mistake?) and now the chromises are kind of "freaking out". They seem unable to find a place to hang out without exerting a tremendous amount of energy. While before they would hang out in a group (all facing the same direction), now they're intermittently scattered, seemingly confused by all the new currents.

How do I know if it's too much for the fish? Will they get stronger/get used to it, or no? Should I turn the powerheads or skimmer off for part of the day?

Btw, I'm hoping to eventually (as in probably many many months from now) get corals.

 

[OrQidz]

It sounds like they are used to flow in only direction. I think most reef fish can adapt to pretty well to current, however you might want to gradually increase it if you can. Maybe just the skimmer for now, then add one PH and let them adapt, then the other.

 

[mcozad829]

By my calculations your probably around 50x flow rate once you consider the displacement of the rock. That's not unrealistically high for a reef tank but is certainly not low flow. The chromis should get used to it they are fairly resilient fish. Perhaps a pump controller that can shut one of the tunzes off at a time would help to not only lower the flow rate but also randomize it a bit, which is helpful for preventing detritus buildup and also extremely beneficial for when you start to get into corals.