Hi Sanjay,
GPH really doesn't mean much, as it measures throughput in the powerhead exhaust. It is localized water velocity that counts: the specific location of a coral colony.
I like to test specific locations in a new tank with a small bit (1"x1") of tissue paper, letting it whip by or drift in the current, and approximating the distance travelled per second.
Here are three different corals (I know you don't have any), and average water velocity readings taken right by them on the real reef --treat these as anecdotal, because as few as only three individuals per species were observed (in as varied locations on the same reef as possible, using an anemometer-type gauge which measured in kph, back in 1994 ...ahh the memories
)
Fungia zamboangensis 90 to 500 cm/sec.
Porites lutea 400 to 1200 cm/sec
Trachyphyllia geoffreyi 100 to 600 cm/sec
Keep in mind that coral tissue expansion in the wild is usually far less than what hobbyists hold as ideal, so tank velocities are mcuh lower. Also, these velocities are averaged: they disguise moments of periodic calm in ebb-and-flow shallow-water situations.
So, while I know you DON'T have any coral on hand, these values should suggest to you what even the wussiest fish can put up with --and the values above are from what I would call calmer parts of the reef
IME, it is a rare tank that comes even close to the water motion found on the real reef. Most need MORE water motion.
HTH.
horge
[This message has been edited by horge (edited 09-25-2000).]
GPH really doesn't mean much, as it measures throughput in the powerhead exhaust. It is localized water velocity that counts: the specific location of a coral colony.
I like to test specific locations in a new tank with a small bit (1"x1") of tissue paper, letting it whip by or drift in the current, and approximating the distance travelled per second.
Here are three different corals (I know you don't have any), and average water velocity readings taken right by them on the real reef --treat these as anecdotal, because as few as only three individuals per species were observed (in as varied locations on the same reef as possible, using an anemometer-type gauge which measured in kph, back in 1994 ...ahh the memories
Fungia zamboangensis 90 to 500 cm/sec.
Porites lutea 400 to 1200 cm/sec
Trachyphyllia geoffreyi 100 to 600 cm/sec
Keep in mind that coral tissue expansion in the wild is usually far less than what hobbyists hold as ideal, so tank velocities are mcuh lower. Also, these velocities are averaged: they disguise moments of periodic calm in ebb-and-flow shallow-water situations.
So, while I know you DON'T have any coral on hand, these values should suggest to you what even the wussiest fish can put up with --and the values above are from what I would call calmer parts of the reef
IME, it is a rare tank that comes even close to the water motion found on the real reef. Most need MORE water motion.
HTH.
horge
[This message has been edited by horge (edited 09-25-2000).]