Flow

[HurricaneCaleb]

I have a 75 gal drilled tank with wet/dry. The return puts off a good bit of flow on the surface. How many power heads do I need? I plan on starting slow, mushrooms and other tough things. As I learn more I would like to step up the stock list.

[jon99]

If by "starting slow" you mean you will mainly be keeping soft corals to begin with I would say a minimum is 10-20X your tank size (750-1500gph). Mushrooms and many other soft coral don't necssarily require high flow like many of the sps. However, more flow helps cut down on algae as well as helps keep things clean by keeping detriotous suspended long enough to make it to you protein skimmer. Most importantly you want random flow. Powerheads generally don't cut it unless you have some way of randomizing the flow.

[biecacka]

this is a loaded question......how many GPH is the return pump putting out? how is the rock work set up? how many return lines do you have? some ppl say for softy lps tanks you want 25x or so the flow of the size of the tank (75x25 =1875 GPH for your tank) but i dont think thats always the best answer, i think more importantly you try to keep no dead spots in the tank that should be a good starting point
HTH
corey

[HurricaneCaleb]

Jon, would you recommend a wave maker then?

I dont know the specs on my return pump, came with the wet/dry, no marking that I have seen.

The return is at the top left corner, what is proper placement of the power heads/ wave maker? Middle, low, opposite side?

I have around 70lbs of lr arranged like a valley, high in back right corner, sloping down to front middle, high on left side sloping down, open in the middle

[jon99]

Originally Posted by HurricaneCaleb

Jon, would you recommend a wave maker then?

I dont know the specs on my return pump, came with the wet/dry, no marking that I have seen.

The return is at the top left corner, what is proper placement of the power heads/ wave maker? Middle, low, opposite side?

I have around 70lbs of lr arranged like a valley, high in back right corner, sloping down to front middle, high on left side sloping down, open in the middle

Sure, wave makers are great, but there are so many different types. Sea swirls, SCWD's, pump timers, wave boxes, rotating water deflectors, etc etc etc. Do some reasearch and see some in action before you decide on what you like best. Lots of youtube videos of wavemakers at work. The basic idea behind a wavemaker is to randomize flow. Ideally you want to mimic the swaying back and forth wave like motion of a natural reef. Sometimes more turbulent, randomizing flow, is by placing a couple of powerheads on opposite ends of the tank pointing toward each other... better yet, position them so they blow the water into a nearby corner of the tank so the current "bounces" out of the corner and randomly reflects back into the tank. Most importantly keep coral out of the direct path of a pump or powerhead. What you don't want is a coral getting constanly hit by a steady non-stop current from the same direction all day long.

The return pump can be counted toward your total flow in the tank. If you have no idea how much gph it pushes... I'd just discount it all together and pretend it's not there. Sticking to the 10-20X the tank size you'll be in no danger of having too much flow. And rememeber this is just a very general guidline for minimum flow for a reef tank to give you something to start with. As you prgress you'll undoubtedly want to add more.

As far as placement... again there is no right or wrong answer. The idea is to create flow in every portion of the tank so there is no "dea zone" where detriotous builds up. There are endless possibilities on doing this. What you use and how many will determine where best placement is. At the very least you want two sources of flow, one on the right and one on the left side. Try both in the middle, try on high one low, see what seemes to keep the water moving the best.

[jon99]

Originally Posted by biecacka

this is a loaded question......how many GPH is the return pump putting out? how is the rock work set up? how many return lines do you have? some ppl say for softy lps tanks you want 25x or so the flow of the size of the tank (75x25 =1875 GPH for your tank) but i dont think thats always the best answer, i think more importantly you try to keep no dead spots in the tank that should be a good starting point
HTH
corey

+1
Much like the watts/gal recommendation for lighting, flow rate for a tank based simply on it's size is often times overly simplifying things. Too many variables for the recommendation to be very accurate. However, I think it's a good place to start.