Tank turnover too high?

[BeaverLakeAndy]

Is there a such thing as too much flow? My return pump is rated at 1,900 gph and it's at 100% power. I have two Tunze powerheads running in pulse inverse of each other. They run at 100% and 50%. They are rated at 2,510 gph at 100%. By my calculation the system is running at 49.26 times turnover per hour.

It's 125 gallon tank with sump. Total water volume after displacement is 115 gallons. It just finished cycling and right now it's FOWLR, but will be mixed reef soon. Is the flow/turnover too high?

 

[Sjaako]

I dont think it is to high, perfect for SPS.
U can place your LPS at places with less flow.

 

[W1ngz]

There is such a thing as too much. Your filtration is more efficient if things aren't flying through the sump. Many corals won't like being blasted, and prefer a gentle flow.

Two different numbers to look at here.
Turnover (through the overflow sump and return). The guidelines I've always seen is 3-5 times tank volume. There's no need to rush your water through the filtration, and more just makes more noise, splashing and salt spray. I'd cut your return to 40%-50%.

Flow (movement inside the tank) the common guidelines are 20x volume for soft corals, 30ish for LPS and 40x for SPS. For a mixed reef, you'll want about 30x, with a few higher flow areas where a powerhead is dedicated to a particular shelf of rock, or the crest of your rockwork for higher flow corals.

 

[BeaverLakeAndy]

There is such a thing as too much. Your filtration is more efficient if things aren't flying through the sump. Many corals won't like being blasted, and prefer a gentle flow.

Two different numbers to look at here.
Turnover (through the overflow sump and return). The guidelines I've always seen is 3-5 times tank volume. There's no need to rush your water through the filtration, and more just makes more noise, splashing and salt spray. I'd cut your return to 40%-50%.

Flow (movement inside the tank) the common guidelines are 20x volume for soft corals, 30ish for LPS and 40x for SPS. For a mixed reef, you'll want about 30x, with a few higher flow areas where a powerhead is dedicated to a particular shelf of rock, or the crest of your rockwork for higher flow corals.

I've a powerhead on each end of the tank with a rock shelf situated on each half of the tank as well. So I believe what you're saying is what I've already got as far as powerheads go. Here's a photo of the tank with the rock formations.

If I cut the return pump power down to 50% it looks like it'd come out to about 8.26 times turnover through the sump. Add that to the powerheads and it looks to be right at 41x turnover.

40% of the return pump would put the turnover rate including the powerheads at about 39.35x per hour, but 6.6x through the sump.

Thoughts?

 

[W1ngz]

They're two separate numbers, you shouldn't add them since the return is better kept high enough to break the siphon when the pump stops, and being pointed across the water surface for gas exchange and moving the oils around so they go down the overflow instead of causing a slick in the middle.

From your return pump calculation, you also have to subtract head height, or the weight of the water column in the pipe. The manufacturer should have a load graph for your pump so you can work it out. At 40%, with head pressure I'd bet you end up closer to 5x, not 8.26.

 

[W1ngz]

Looking at your tank, and how it's placed in the space, you might like to think about the long views from the ends, and not spoil them with pumps. My favorite view when I had a 75 was down the long axis.

3 or 4 smaller powerheads across the back, up high and out of sight would really improve it visually.

 

[BeaverLakeAndy]

They're two separate numbers, you shouldn't add them since the return is better kept high enough to break the siphon when the pump stops, and being pointed across the water surface for gas exchange and moving the oils around so they go down the overflow instead of causing a slick in the middle.

From your return pump calculation, you also have to subtract head height, or the weight of the water column in the pipe. The manufacturer should have a load graph for your pump so you can work it out. At 40%, with head pressure I'd bet you end up closer to 5x, not 8.26.

The return pump is a Current eFlux 6010. I'm actually unable to find a load graph for it, but there's approximately 4-5 feet of 1" PVC on the return line.

For a siphon break I've got a small hole drilled just below the water line on the return pipe. It effectively breaks the siphon, and the sump holds the amount of water that does be back siphoned.

 

[W1ngz]

Check the 'Flow chart' link on that page. At about 5' it looks like you'll have about 1500gph.

 

[BeaverLakeAndy]

Check the 'Flow chart' link on that page. At about 5' it looks like you'll have about 1500gph.

I see it now! So at 50% power it'd be approximately 6.5x turnover through the sump. Too high still?

 

[fishface NJ]

I see it now! So at 50% power it'd be approximately 6.5x turnover through the sump. Too high still?

I would have it less turnover

 

[W1ngz]

I see it now! So at 50% power it'd be approximately 6.5x turnover through the sump. Too high still?

Getting warmer! I think you might find it better a little lower but the rest will be dictated by the water levels in the sump and how much noise it makes as you tune the overflow. I can't stand even the slightest trickling noise from my system.

 

[BeaverLakeAndy]

Getting warmer! I think you might find it better a little lower but the rest will be dictated by the water levels in the sump and how much noise it makes as you tune the overflow. I can't stand even the slightest trickling noise from my system.

The only sound in my sump right now is the flow into the filter sock, and it's relatively quiet. You can barely hear it from the next room. I'll start tinkering with the return pump rate this evening. Sounds like the consensus is I should drop the power to about 40-50% on the return.

 

[theMeat]

You’re getting good advice.
Keep an eye on that current pump. Have had two that had the gph fall way off after about a year

 

[W1ngz]

You can barely hear it from the next room.

The next room?? I would go insane. LOL
The prime TV viewing spot on my sofa is 5' away from my tank. Noise isn't an option for me.

 

[BeaverLakeAndy]

The next room?? I would go insane. LOL
The prime TV viewing spot on my sofa is 5' away from my tank. Noise isn't an option for me.

lol, it's really not bad. It's in our office, and the living room/TV room is just around the entryway. You can't hear it with the TV on. I'd say it's 10 steps to my recliner from the tank.

 

[Cwentz758]

Looking at your tank, and how it's placed in the space, you might like to think about the long views from the ends, and not spoil them with pumps. My favorite view when I had a 75 was down the long axis.

3 or 4 smaller powerheads across the back, up high and out of sight would really improve it visually.

Did you do this with your power heads? I’m looking at placing my two MP10s on the back glass high instead of opposing ends.

 

[W1ngz]

Did you do this with your power heads? I’m looking at placing my two MP10s on the back glass high instead of opposing ends.

I have mine on the back up high, but I have a cube with 3 viewable sides. You just have to watch the way the flow hits the tank, because anything you might want to put down low and in front may get blasted by the water being deflected by the glass.

 

[Cwentz758]

I have mine on the back up high, but I have a cube with 3 viewable sides. You just have to watch the way the flow hits the tank, because anything you might want to put down low and in front may get blasted by the water being deflected by the glass.

Just sand really. Which I need hit because my diatoms are sitting on the sand. My corals are soft except an Acro stick I got that’s up high

 

[Glott3133]

Looking at your tank, and how it's placed in the space, you might like to think about the long views from the ends, and not spoil them with pumps. My favorite view when I had a 75 was down the long axis.

3 or 4 smaller powerheads across the back, up high and out of sight would really improve it visually.

Can you explain how you setup the powerheads on your 75g. I have a 75g tank with 3 wavemakers. 1 at each end (focused on a birds nest and montipora; and the other focused on a chalice, monti, and hydnophora) and 1 in the back that shoots upwards. I have a mix of softies, SPS, and LPS. They are all doing great, but I find myself always questioning the position of the wavemakers when I see the polyps not opening on a particular coral.

 

[W1ngz]

I had a pair of hydor 1150s at what most consider the 'end' of the tank, but for me was the back since it was a peninsula. They were pushing along the space between the rock and the glass, aimed at about a 30deg down angle. The third was in the upper far corner of one of the large panes, where I had my return line. It was aimed across the tank to provide more turbulent flow for the corals I had placed on that side of the tank.