TALL column tank -- how to do water changes?

I have a TALL column tank (16" diameter x 48" tall). It's a 55-gallon. We have a powerhead at the top that pulls up water through a 1" intake column (UGF... not the best, yes I know..).

Here's the problem:

Since the powerhead always has to be on to keep the water flowing through the gravel, I can only take out about 1 gallon of water (maybe 2 gallons) at a time before the water level is too low for the powerhead to operate. What I've been doing is taking out a gallon and the refilling with a fresh gallon of water --- repeat 5 - 10 times.

I know it would be much better for the water to take out 5-10 gallons at once and refill with 5-10 gallons all at once. I just haven't figured out how to do that without having to stop the powerhead ...

Any ideas?

H3D said:

Why can't you stop the powerhead, change the water, then restart it?

Click to expand...

My understanding is that it is detrimental to the beneficial bacteria living underneath the UGF to turn off the flow of water. I could be wrong but this cuts off the supply of oxygen.

Maybe I should be able to turn off the powerhead for short periods of time, say 10-20 minutes?

Can someone confirm this?

AWESOME!

Thanks for your response and information!