How to gauge GPH?

[kerrnel]

In my 10g tank, I'm using a PF rated for a 20G tank, as well as a PH rated for a 20G tank.

The PF is 105gph while the PH is 127gph. Theoretically, I can move about 230gph if I jack it all up to full. This in itself begs the question whether or not I should do that. My understanding is 5x/hr is sufficient, so I'd be looking at maybe 50gph. If someone knows of an existing thread where high flow vs. normal flow is discussed, I'd love to read it...please let me know!

My dilemma is that I can throttle back the PH to an arbitrary minimum setting, and I can throttle back the PF to "low", but that really doesn't tell me much. Is there a rule of thumb or any other way to effectively gauge how much water you're actually moving in a tank?

Mike.

[Fly Guy]

flow is relevant. it depends on how exactly the flow is achieved as well as how a tank is aquascaped.

for instance, the jet stream coming out of a maxijet isnt nearly as usable of flow as what comes out of a tunze. so you could use twice as much flow with a tunze as it wont be ripping the flesh off of stuff and you have more choices of where exactly to aim it

5x isnt nearly enough. no reef tank should have any less than 20 imo. 50x is by no means is too much assuming it isnt ticking off any corals and you can keep the sand on the ground

[crvz]

5x turnover may be good for a freshwater tank, but salt water needs to be quite a bit higher than that, ensure that there are not any dead zones in the tank. I've got about 50x on my setup, coming from mulitiple sources to spread it out as well as I can. The only thing you want to ensure is that you're not blasting any corals and that the sand bed isnt disturbed.