How much flow do I need?

[serbusfish]

I am unsure how much flow I need. My tank is 75 gallons, and I have 2x Jebao WP25 powerheads. I have no sump so no other forms of water movement. Each powerhead will do 8000 litres (1760 gallons) an hour. I currently have them set to around 30 - 40% speed, one on pulse the other on constant, and I am worried this is too much flow for my new clownfish as they seem to struggle against the flow. Basically I am just wondering what sort of turnover I need to aim for?

 

[thegrun]

For a fish only tank 20 to 30 turn overs per hour is fine (1500-2250 for your tank), for soft corals 30 turn overs, for SPS corals 40 turn overs plus.

 

[jem454]

I have 2 wp25 in my 125 running on else mode.
You can turn them up till it doesn't cause a sandstorm, the fish get used to it.

I would put one on else, the other on wave mode.

 

[serbusfish]

For a fish only tank 20 to 30 turn overs per hour is fine (1500-2250 for your tank), for soft corals 30 turn overs, for SPS corals 40 turn overs plus.

I plan to have softies and LPS, does 30x count for LPS too?

I have 2 wp25 in my 125 running on else mode.
You can turn them up till it doesn't cause a sandstorm, the fish get used to it.

I would put one on else, the other on wave mode.

Im not sure how to put them on different modes, I have the dual controller and there is one button that goes through the different modes, I dont know how to select a mode for each individual powerhead. The sand already gets moved a little with my current settings.

 

[whosurcaddie]

You would have a total of 50x turnover with them at full blast. For LPS 40-50x turnover is what you want. A lot of it will depend on your rock work though some tanks need less flow because of their open structure some need more for the exact opposite reason.

 

[top shelf]

You would have a total of 50x turnover with them at full blast. For LPS 40-50x turnover is what you want. A lot of it will depend on your rock work though some tanks need less flow because of their open structure some need more for the exact opposite reason.

What he said, a lot of it is dependent on your rock work. I had a minimalist scape in my 20 long and 2 koralia 425's was plenty then I added a decent size rock in the middle of my 2 islands and ended up having to switch one out with a koralia 600.

 

[serbusfish]

You would have a total of 50x turnover with them at full blast. For LPS 40-50x turnover is what you want. A lot of it will depend on your rock work though some tanks need less flow because of their open structure some need more for the exact opposite reason.

What he said, a lot of it is dependent on your rock work. I had a minimalist scape in my 20 long and 2 koralia 425's was plenty then I added a decent size rock in the middle of my 2 islands and ended up having to switch one out with a koralia 600.

I think my rock work would be considered fairly open/minimalistic, what do you think?

 

[dkeller_nc]

Yes, I'd consider your rockwork minimalistic. Since you don't have any corals in the tank, there's no reason you can't turn your existing powerheads down to 25% or so if your clownfish are struggling against the current. Over time, you can slowly turn the intensity of the flow back up.

 

[coralsnaked]

You would have a total of 50x turnover with them at full blast. For LPS 40-50x turnover is what you want. A lot of it will depend on your rock work though some tanks need less flow because of their open structure some need more for the exact opposite reason.

50X in a 75 = approaching 4000 gph ... maybe a bit too much. Could be OK for an SPS only tank but still probably overkill. 30X is normally sufficient even for most SPS tanks and less maybe 20x for LPS or they may not open all the way. Softies could care less about more than 10X

 

[dkeller_nc]

By the way - I took a look at your build thread. Considering that you first filled the tank on the 19th of March, I'd recommend not adding additional fish or coral to the tank for another 3-4 weeks. Even when using true live rock, there's a good bit of "settling down" with respect to the tank's water chemistry, and you'll want to stock the tank slowly. The adage that "nothing good happens quickly in a reef tank" is very true.

 

[serbusfish]

50X in a 75 = approaching 4000 gph ... maybe a bit too much. Could be OK for an SPS only tank but still probably overkill. 30X is normally sufficient even for most SPS tanks and less maybe 20x for LPS or they may not open all the way. Softies could care less about more than 10X

OK cheers, it is roughly at 20x now I think so i'll leave it and see how it goes.

By the way - I took a look at your build thread. Considering that you first filled the tank on the 19th of March, I'd recommend not adding additional fish or coral to the tank for another 3-4 weeks. Even when using true live rock, there's a good bit of "settling down" with respect to the tank's water chemistry, and you'll want to stock the tank slowly. The adage that "nothing good happens quickly in a reef tank" is very true.

Yes I am going slow, I am not going to add anything else until I have a proper quarantine tank setup, I figured tank raised clowns would be a fairly safe fish to start with, and my LFS have had this pair in for about a month and they seem fine.

 

[dkeller_nc]

Yes I am going slow, I am not going to add anything else until I have a proper quarantine tank setup, I figured tank raised clowns would be a fairly safe fish to start with, and my LFS have had this pair in for about a month and they seem fine.

Unfortunately the fish's origin doesn't have that much to do with whether it'll be healthy when you purchase it from an LFS. The issue is the way fish are distributed and sold, and the nature of the diseases that typically affect marine fish, particularly ich.

Any marine life distributor or LFS, by definition, cycles through many fish in the same life support system every few days/weeks. It would be extremely costly to set-up individual tanks with their own life support systems for these fish, then tear it down and sterilize it once the fish is sold.

So these businesses run many tanks on the same filtration system. Most run UV sterilizers to control disease transmission among the livestock, but particularly in the case of cryptocaryon irritans (saltwater ich), it takes a very large UV unit to kill the infectious stage in the water, and the most of the life cycle of the parasite isn't actually in the water - it's either attached to the infected fish or encysted on the tank walls, substrate, etc...

Given these circumstances, it's nearly impossible for a distributor or retailer to keep their systems and fish completely ich free, so the thought about "quarantine everything wet" is based on the assumption that anything we purchase potentially can introduce ich and/or other fish diseases into our tanks.