How much is too much flow?

[Stanley]

My tank is cycling nicely thanks to everyone's help. Thank you all!

I have seen some estimates for water movement and 10 X per hour seems to be the "Magic" number.

I have 3 maxi-jet 600 power heads going plus the 1200 on my skimmer which comes out to be 775 gallons/hour of water flow.

I estimate that after my DSB and live rock displacement that I have approximately 40 gallons of water in my 46 gallon tank.

I have close to 20 X per hour water flow.

Too much? Way too much?

[BrianH]

IMHO it is very difficult to have too much water flow unless your talking about a species specific tank like seahorses. Remember that the ocean has a huge amount of current. Also most skimmers use pumps to draw water and to power their bubble creation so even if you include this in your turnover (which I would not) the flow is reduced by at least 60 - 75%.

Brian

[hawksview]

I agree with more waterflow.Since i have added a second submersible pump to my 55 gal everything in the tank looks better

[fishfreek]

YOu dont need to get as scientific as in calculating the amount of water after displcement. The 1 rate is usually calculated on tank capacity empty. The reason is that each tank has its set dimentions that you have to flow the water over.

1 is just a good average number. I myself have close to 15X and I could use some additional flow in spots. The key is to balance the flow with what you want to keep. If you have a bunch of corals that need high flow then 2 would be better for them than 1. But at the same time you dont want the current beating on them.

Flow should not be confused with intensity of the current.

[loganj]

One other thing to remember is that turbulence is better than laminar flow. You don't want a PH pointed directly at a coral going 24/7. If your PH's can be directed against each other so that the flow collides and creates turbulence, that is much better. A wave maker is a good upgrade also. I have had good luck with the Natural Wave powerstrip. It's not as high tech as many of the others, but it'll get the job done...and it's cheap. I have one 20g tank with about 450gph.

[Stanley]

The natural wave is something you (loganj) had brought to my attention on a previous post and I plan on buying one of those shortly. I thought I would run two PH's on that and have two pointing at each other from the ends of the tank. That's what prompted the post, I plan on adding ANOTHER PH and thought maybe that would be severe overkill. Sounds like I'm in the ballpark though.

Thanks![/quote]

[fishfreek]

There are also things called surge devices. THey are very interesting in how they work. Basicly they involve a container that is mounted someplace above the tank. A pump pumps water up into this container. When the container reaches a point a float rises and it opens a hole in the bottom (simular to a toliet tank) water then rushes down to the tank and into the tank creating a surge (aka wave).

The entire process is repeated because the pump continues to fill the container above till the process starts over again.

[Stanley]

That sounds kind of cool. I haven't seen anything like that before, but it doesn't seem like it would be that hard to construct. I'm also intrigued with the "Squid" (can't remember the correct anogram) product that you pump water into and it alternates between 2 outlets. Has anyone had success with those? I'm a tad concerned about noise with whatever I do. My girlfriend is excited about the tank but has some reservations that it will look like a biology lab in the living room and has already commented on the noise from the skimmer.

[fishfreek]

I have heard about the squid. From what i understand you really need a high speed pump to make this thing work like its designed. The resistance that is incured inside the device is such that alot of people have noticed a 20% or higher decrese in pump output after putting one on.

I have no experence personally with it so I can only comment from what I have read on the net.

[loganj]

I'd run three PH's on the natural wave. Two of the ports are timed alternately. The third operates on a longer interval. That way you don't have the same current all the time. The plans for the surge device can be found on page 341 of "Aquarium Corals" by Eric Borneman. His design actually uses a toilet flapper...pretty neat.