too much flow?

[Constantin]

I placed this in the advanced section because water flow is one of the most important aspects of a reef, and I would appreciate your detailed input on my setup.

I have a 72x30x36 tall tank, with dual internal overflows, so actual inside volume is not that great.

I have 2 hammerheads - 1 for return, one on the 4 motions closed loop ver. 3 - the opposing version 1+3, 2+4 open , and 2 vortech mp40 running in reefcrest anti sync mode.

here is a picture of my setup -

It seems that the closed loop hammerhead is a bit too strong for my tank, there is almost no headloss, so its getting its full 5800gph - my problem is that when 4 motions opens only 2 out of the 4 1" pipes, it pumps about 2500gph out of a 1" pipe, and the fish and corals that are in the way dont seem to like that - i have tried not placing any in the way, but in general, there seems to be too much flow in the tank, at least compared to most the other reef tanks I have seen.

I am trying to keep some simple LPS(bubble, frogspawn, torch) and they dont seem to be too happy(doh), they might adjust but still...

Fish also seem to be acting a bit more naturally when i throttle down the closed loop.


I was thinking of replacing the closed loop for a controllable red dragon(that would be cool).
As far as the return pump - I dont know of any better options than the hammerhead, even restricted, its energy consumption vs flow is better than a pressure rated iwaki, even though maybe with a couple eductors, it might work out better... dunno.

Flow gurus, sps keepers tell me what you think, am I just looking for trouble where there is none (tank has been running this way for 6 months, params are very good, but the flow just feels wrong!, even though the sand is silky white and everything is in suspension)

 

[beeker]

Do you really need the Vortechs with all that Closed loop flow?

IMO i'd move and Mp40 to the back wall and have it pushing water forward against the glass, this will give you an undertow to the Mp40 but also it will react with your closed loop outputs maybe minamizing the the power of their streams or atleast the waterflow will push them into a direction your corals may enjoy more instead of being blasted and it would probably give more randomness to the tank

I don't have a tank as big as yours but 10000gph just through the closed loop is a lot and you might not need both mp 40's until the tank is grown in

10000/75g...if that considering the water the rock displaces you still have a ton of turnover 100+ times an hour which is more than enough

 

[chuckreef]

Where is the suction(s) for the closed loop?

I would swap the Hammerhead on the closed loop for a Dart, and I would replace the 3/4' retruns with 1 1'4 or 1/1/2 ich PVC.

 

[Constantin]

the suction is in the middle.

The closed loop is only 5700gph or so... I like the MP40 because they create abit more randomness and also wider flow

As far as the back glass goes - it would be too much to put 2 x mp40s on there, Tank is only 30 inches wide.

The plumbing is 1.5 for the return (as is from the hammerhead) but it splits to 2 x 1"(yes i know thats less than the 1.5 but... i didnt plan on going with a hammerhead, but when i looked at the flow curves, that seemed the best option even with the restricted flow.

 

[Constantin]

Do you really need the Vortechs with all that Closed loop flow?

I don't have a tank as big as yours but 10000gph just through the closed loop is a lot and you might not need both mp 40's until the tank is grown in

10000/75g...if that considering the water the rock displaces you still have a ton of turnover 100+ times an hour which is more than enough

its not 4 x 2500gph ... only 2 are fully open at the same time, the pump itself is 5700gph.
the tank is a 340g tank.. not sure what the 75g means.

 

[jeffreylesser]

You could switch the drum on the oceansmotions. I use a drum that has 3 on, 1 off for the same reason. This doesn't solve the overall flow issue, but it will reduce the output of your jets.

 

[Constantin]

well, i really wanted some input on what people here think would be a good flow for my tank, should I perhaps post in the big tanks section?

 

[KarlBob]

Posting in the large tanks forum might be a good idea.

I've seen people posting that natural reefs receive incredible amounts of flow, and that it would be extremely difficult for us to exceed the natural flow level. On the other hand, natural flow generally doesn't come in the form of jets.

A frogspawn or a torch might be able to adapt to relatively high flow, but my (limited) personal experience and everything I've read and heard about bubble corals suggests that direct exposure to one of your jets would be extremely unhealthy.

 

[Constantin]

obviously neither the frogspawn nor the bubble coral gets explosed to the jets...

it would seem (at least from my diving experiences) that natural flow in reefs is not as vigorous(in other words, the whole volume of my tank would be displaced within a few seconds(within the same volume, but the flow would be very even. Also, a 5600 gph pump would cause more overall movement than the 5600gph within a given tank(the jettier the flow, the more water turbulence it causes)

 

[gokarter88]

that seems like the flow would be fine. you have the outputs spaced good i think. if you don't think the corals like the 2500gph flow coming from the 1" i would enlarge the pipe if you can wider flow will create a nicer flow and the corals will like it much more.

 

[NyReefNoob]

or add a split on the end returns on the closed loop, which will still keep the same amount of water but disperse it into less flow on each output. if you put the vortchs on back wall and dial down wont be much of a problem. lol or send me the 40's and ill send you the 20's

 

[DGAF]

Just make it simple, put heavy duty valves on your pumps and then you can dial in the exact amount of flow that your system likes or what it takes for the corals to thrive. As for the mp40s just experiment with different locations and keep notes on what water flows or currents are formed by your live rock formations and the walls of the tank. And if more flow is needed I would add another mp40 and find a good spot for it.

Good Luck with your tank...

JP

 

[overklok]

You need to get chaotic flow working for you. Direct constant streams are not good for any coral, they need a break. I am running 3 mp40's in a 90 at full blast. I have good coral growth, fish get blown around, but they seem to love it.

 

[H20ENG]

How about adding wyes to your outlets so the flow is dispersed more evenly? Or simply doubling the amouint of outlets on each bulkhead.
Your problem is velocity, not flow

 

[Bud Reeferman]

I'd move the overflow returns to the side instead of coming off the face. More visually pleasing with less Loc-Line showing. And since you're flow goes in the direction facing the side, you've nothing to lose.

IMO, powerheads will give you more flexibility to aim directional flow than those two side wall returns. As you tank matures, you'll appreciate the flexibility to redirect flow to match your inhabitants preferences.

To minimize powerheads, you might want to design with a Wavebox in mind.

Remember, since the tank is so shallow back to front, yet so tall (get a good ladder), you're going to be stacking rock 30" high against the back wall in order to get some height. If you're going with a sand bed, the two front-most returns are going to be constantly blowing sand and could be more trouble than they're worth.