90gallon tank, flowrate?

"Michael" wrote in message
...
OK,

I'm setting up my 90 gallon tank that's been in storage for awhile.
Previously I used a Magnum 350, with a sponge sleeve around the
carbon/ammo
chips, and Undergravel with two 270 gpm powerheads. The canister and
the
powerheads where pretty much shot so:

I bought a Filstar XP2 (300gpm canister), and two new 300gpm powerheads
for
the undergravel.

900gpm into a 90g with little tetras is a bit...... hmmm.... like a good
martini, you are supposed to stir, not shake ;~)

The aquarium will be a tropical community tank, mainly tetras/rasboros
a few
angels, etc.

I added 6 rasboros to the tank to start it cycling. The fish don't
appear
to have many places to rest other than right above the powerheads, or
near
the bottom of the tank.

I'd fishless cycle the tank. If you want to use fish, Rasboras would not
be my first choice, and only 6 in a 90g is like ****ing in an ocean. I
load to about 30%, or 30 fish inches or 30 Rasboras. Much easier to
fishless cycle IMHO.

Is this setup going to be OK, or am I moving to much water? Should I
reduce
the size of the powerheads, or take the UG out all together, I'm sure
the
LFS would swap the powerheads for me, or give me a refund? I could
also
change the configuration of the filstar flowing back into the tank, and
the
powerheads to create a little deader water? I can also add some
structure
to the tank, such as a big rock, that would create some dead spots for
the
fish to rest....

If you can, dial the powerheads to their minimum. UGFs should run at
4-5x volume, or 360 to 450gpm, so at 470, you are just a bit high. Maybe
adding a diffuser or attaching some plastic Hornwort to the outlet would
help. From a turbulence perspective, the 300 gpm canister is not even
needed. From a mechanical filtrarion perspective, it is very needed.
Try to diffuse this as well (ie: spraybars, rocks, plants). New empty
tanks always seem to have too much turbulence. It reduces as your pumps
break in, you add rocks, your plants and fish grow. Having said all
that, keep in mind that neither Angels or tetras need or appreciate a lot
of turbulence. JMO

NetMax

What do you think ?

thanks,
Michael

"Michael" wrote in message ...
I bought a Filstar XP2 (300gpm canister), and two new 300gpm powerheads for
the undergravel.

I know you already have fish in there, but you may want to think about
removing the undergravel filters. I kept tanks with UGFs for about 13
years, so I speak with experience when I say they're not worth it.

Over time, they accumulate enough mulm to really drop your pH. They
require very thorough vacuuming, limiting your ability to add plants
and such. And, getting back to your original question, you'll have an
awfully high flowrate for the types of fish you're getting. (Many
loaches, by comparison, would love that much current.)

A 300 gpm canister should be adequate filtration. If you can arrange
it so that the intake and outlet are on opposite ends of the tank, you
should get plenty of circulation as well.

- Jim