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Flow Questions for experienced acropora keepers

Consider measuring alk daily and watch how it drops, that will help you gauge how much water to change and when.

Edit, you are already dosing, then what are you trying to dilute or replenish with the water changes. Measure that and change based on that parameter movement.

I always have had higher p04 since I had the tank, weekly water changes are solely to target p04 not really for any other specific reason.

Haven't had any type of alage in the tank in 2 years despite high po4. Only goal of droping them is for sps. Otherwise I would probably not be worried about anything seeing everything is happy except a few of the sps.

Even with weekly water changes I can't keep calc alkalinity and mag from droping hence the dosing.
 
I took two videos trying to capture some of the current flow I have.

I also Included a few pictures showing return and wave maker placement.

The two white sps frags on one of the racks are from my idoiot move putting them touching a pavona that I didn't know had swepers at the time. Left them in in case they decided to make a miraculous come back.


 

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Indirect flow is pretty important especially when things start to grow and getting flow between branches becomes more difficult. Flow is how all oxygen and nutrients are brought to coral and how waste is removed. Both flow and light are important and which is more important could probably be debated for hours on end. Both are needed and go hand in hand, but I’ve seen plenty of acros happily grow and survive at 150 par.

Here’s a video from over a year ago of acros in my tank. Not the end all be all in flow, but you can see the type of flow that I try to achieve.

 
Too long haven’t fully read. Flow is super important, but I doubt it’s would cause browning. Keep adding mp10s in different spots until you have too many
I had 7 mp40 running on my bare bottom 6ft 225 gal. Both high (2/3 of the way up) and low (2-3” off bottom)
 
Indirect flow is pretty important especially when things start to grow and getting flow between branches becomes more difficult. Flow is how all oxygen and nutrients are brought to coral and how waste is removed. Both flow and light are important and which is more important could probably be debated for hours on end. Both are needed and go hand in hand, but I’ve seen plenty of acros happily grow and survive at 150 par.

Here’s a video from over a year ago of acros in my tank. Not the end all be all in flow, but you can see the type of flow that I try to achieve.

THIS!
 
Too long haven’t fully read. Flow is super important, but I doubt it’s would cause browning. Keep adding mp10s in different spots until you have too many
I had 7 mp40 running on my bare bottom 6ft 225 gal. Both high (2/3 of the way up) and low (2-3” off bottom)
Thanks, I will try to barter for or buy another used mp10 as soon as I'm able too.
 
@RandyC
Thanks alot your video gives me prospective. My sps polyps barely move at all when they extend. So i'm confident I need alot more flow. I will try to rethink my coral placement. Hopefully I can shift some corals around to in order to be able to increase the for at the top.
 
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Agree with most of what is posted above. It's good to see the type of polyp extension and motion that you want. But also why strong direct constant flow is bad too for colony shaping and why you want to place the pumps high on the tank without drawing a vortex of air and aimed correctly.

Abe is the SPS master:
Thanks took me a while to have time to watch it, this is the best video I've seen on the subject so far. The calculations he showed will certainly help me on the new tank. On the current tank, I'm more clearly beginning to see the issue of mixed reef verse species specific tank. It’s like trying to thread the needle with keeping everything happy.
 
Only goal of droping them is for sps.
Why? I haven't seen any evidence this effects growth in the real tank. Yes, theoretically phosphates inhibits skeletal growth, but I haven't seen any rates cited or papers published on this. And my theory is that the biological gains of feeding more outweigh the chemical inhibition of the phosphate.

Looks like you are on the right track looking into flow, and I agree dosing is the way to go.
 
Why? I haven't seen any evidence this effects growth in the real tank. Yes, theoretically phosphates inhibits skeletal growth, but I haven't seen any rates cited or papers published on this. And my theory is that the biological gains of feeding more outweigh the chemical inhibition of the phosphate.

Looks like you are on the right track looking into flow, and I agree dosing is the way to go.


My first hand knowledge/experience is limited on the subject. So a good portion of my foucs stems from youtube videos, advice from members, and posts here that discuss the subject. Most imply that you want really low Po4 like .02-.03 levels. (When I say lower po4 that's not my aim.) Frankly I wouldn't like trying to balance on the knifes edge of bottoming them out.

I've been struggling to get mine under 1.0. My last test shower .61 lowest I've had them since right after I started the tank.

I don't have a specific number I want to reach as there is so many conflicting view points. When I say lower them for sps it's only a part of the whole effort in order to improve sps growth and coloration. The whole focus I think involves lighting, proper flow, nutrient control, and stable parameters. (I should possibly add feeding as a consideration based on your view)

When you say feeding more, I've never once looked deeper into it. I always avoided it due to high phosphates. Only recently have I started feeding the corals again.

I would love to hear a little more on your theory if you ever have time.
 
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Why? I haven't seen any evidence this effects growth in the real tank. Yes, theoretically phosphates inhibits skeletal growth, but I haven't seen any rates cited or papers published on this. And my theory is that the biological gains of feeding more outweigh the chemical inhibition of the phosphate.

Looks like you are on the right track looking into flow, and I agree dosing is the way to go.

Look at Rich Ross's tank. Great growth, high phosphate.
 
I am not seeing much flow hitting the SPS in back, I don't think I saw a single polyp move on the purple stylo. Looks like the toches in front are getting more than enough though, so you probably have water hitting the front glass and then rushing back to the pump. I would adjust your pump locations so that return flow is hitting the SPS instead of the LPS. I am in the camp that you don't need a ton of pumps to achieve good flow, you just need them positioned correctly. See my own journal post on this or any of Jake Adams videos - he does not use many pumps, and simply opts for long-period gyre waves to move a ton of water.

Here's a flow video of my own SPS, looks very similar to @RandyC , hope it helps:


The big challenge is that if you get heavy enough flow for your SPS, the LPS tend to suffer. It can be really tricky getting flow just right for both.
 
@derek_SR


I adjusted the waver makers (higher)and return nozzels(direction) right after seeing @RandyC video. I also increased the max flow rate of tbe mp10 from 65 to 75%.
This is a follow up video after those adjustments.

There is 2 areas of flow I dislike.
1. Is near very bottom of the tank where those hammers are near the toadstool.
2. Is on the left side of the tank where I have the two hammers on the rack.

Those areas were getting better flow before I shifted the wavemakers higher. I may just say screw it and add the third wave maker back to cover those lower areas. (Closer to how i had things beforei got the mp10)

* I hope to be able to get one more mp10 at some point for the other side of the tank than I think I could have full coverage with minor adjustments to their flow pattern and flow rates. Without needing the extra wavemakers.

If this wasn't a all in one- i could put 1 of the wavemakers on the back wall which might be more ideal.

Any feed back based on the this video?
 
I am not seeing much flow hitting the SPS in back, I don't think I saw a single polyp move on the purple stylo. Looks like the toches in front are getting more than enough though, so you probably have water hitting the front glass and then rushing back to the pump. I would adjust your pump locations so that return flow is hitting the SPS instead of the LPS. I am in the camp that you don't need a ton of pumps to achieve good flow, you just need them positioned correctly. See my own journal post on this or any of Jake Adams videos - he does not use many pumps, and simply opts for long-period gyre waves to move a ton of water.

Here's a flow video of my own SPS, looks very similar to @RandyC , hope it helps:


The big challenge is that if you get heavy enough flow for your SPS, the LPS tend to suffer. It can be really tricky getting flow just right for both.
Dong Zou and Abe Tirona both swear by creating a standing wave for their tanks then having targeted power heads in big tanks to disrupt detritus beds, as did Jake in some ways (he was all about the washing machine type of flow).

I use the "gyre" mode at 50% on my MP10s with wide flow that swaps direction every 20 min. With the wide flow urchin wet side guards I get pretty good movement in a clockwise and counterclockwise loop. Strong flow out the top of the tank (mount them as close to the surface as you can without drawing air) with a good reverse direction undercurrent. Keeps food suspended and polyps moving without blasting LPS.

If you create a standing wave though, be mindful if you don't have a eurobrace to keep sloshing down.
 
Dong Zou and Abe Tirona both swear by creating a standing wave for their tanks then having targeted power heads in big tanks to disrupt detritus beds, as did Jake in some ways (he was all about the washing machine type of flow).

I use the "gyre" mode at 50% on my MP10s with wide flow that swaps direction every 20 min. With the wide flow urchin wet side guards I get pretty good movement in a clockwise and counterclockwise loop. Strong flow out the top of the tank (mount them as close to the surface as you can without drawing air) with a good reverse direction undercurrent. Keeps food suspended and polyps moving without blasting LPS.

If you create a standing wave though, be mindful if you don't have a eurobrace to keep sloshing down.

How many mp10s do you have?

I love the one that I have, and one more is on my wish list.

I couldn't consider anything that caused sloshing in the 32 as my lights are 2 inches above the water. But definitely something I can play with in the newer tank.

I was trying to mount more euphyllia on the rock work, but dang momma maroon clown wasn't going for it. She would knock them over seconds after I put them in place before the glue and epoxy could cure. Hence I have a lot still on racks.
 
@derek_SR


I adjusted the waver makers (higher)and return nozzels(direction) right after seeing @RandyC video. I also increased the max flow rate of tbe mp10 from 65 to 75%.
This is a follow up video after those adjustments.

There is 2 areas of flow I dislike.
1. Is near very bottom of the tank where those hammers are near the toadstool.
2. Is on the left side of the tank where I have the two hammers on the rack.

Those areas were getting better flow before I shifted the wavemakers higher. I may just say screw it and add the third wave maker back to cover those lower areas. (Closer to how i had things beforei got the mp10)

* I hope to be able to get one more mp10 at some point for the other side of the tank than I think I could have full coverage with minor adjustments to their flow pattern and flow rates. Without needing the extra wavemakers.

If this wasn't a all in one- i could put 1 of the wavemakers on the back wall which might be more ideal.

Any feed back based on the this video?

It looks better, IMO, but there are so few polyps on the SPS it's still hard to tell. I used to move a little torch frag around I had to make it really obvious to see how the flow was in any given spot. You have plenty of frags, you could do the same if you are still curious how the flow looks in any given location. Use a tester torch and drop it next to the SPS you're targetting and see how it looks!

At some point, you have to adjust the corals to the flow. So those dead/low flow spots you're talking about - put mushrooms and stuff there. Or flow-sensitive euphyllia. My euphyllia seem to do the best with as little flow as possible.

Be careful adding pumps - water movement is a weird thing. Sometimes adding another pump that creates a bunch of random flow behaves very unpredictably and can create deadspots or make things worse. They key is to get a LOT of water moving consistently. Adding random pumps pointing all sorts of directions doesn't always accomplish that...

Dong Zou and Abe Tirona both swear by creating a standing wave for their tanks then having targeted power heads in big tanks to disrupt detritus beds, as did Jake in some ways (he was all about the washing machine type of flow).

I use the "gyre" mode at 50% on my MP10s with wide flow that swaps direction every 20 min. With the wide flow urchin wet side guards I get pretty good movement in a clockwise and counterclockwise loop. Strong flow out the top of the tank (mount them as close to the surface as you can without drawing air) with a good reverse direction undercurrent. Keeps food suspended and polyps moving without blasting LPS.

If you create a standing wave though, be mindful if you don't have a eurobrace to keep sloshing down.

I also am a huge fan of the standing wave. It moves literally every molecule of water in the tank! It's also super awesome aesthetically. Agree with what Thomas is saying here too, the easiest way to get good flow is to get big gyre's moving and/or apply a standing wave. The latter is pretty easy to achieve too, I use a $65 jebao pump on one end to make the wave, and a single xf350 on the other end to get the gyre moving. No other pumps in my 6ft tank besides these two. Very, very simple. And I have mega flow.
 
How many mp10s do you have?

I love the one that I have, and one more is on my wish list.

I couldn't consider anything that caused sloshing in the 32 as my lights are 2 inches above the water. But definitely something I can play with in the newer tank.

I was trying to mount more euphyllia on the rock work, but dang momma maroon clown wasn't going for it. She would knock them over seconds after I put them in place before the glue and epoxy could cure. Hence I have a lot still on racks.
Two for a long but narrow 29g which is overkill. I was however able to get a standing wave in there with just one mp10 before. It just is noisy since it's next to my bed. You can make an mp10 out of all the old parts people have on here though, it's really not hard. I actually constructed my second one that way. Wet side, dry side, quiet drive controller box, power supply, and wireless chip (make sure they match).
 
It looks better, IMO, but there are so few polyps on the SPS it's still hard to tell. I used to move a little torch frag around I had to make it really obvious to see how the flow was in any given spot. You have plenty of frags, you could do the same if you are still curious how the flow looks in any given location. Use a tester torch and drop it next to the SPS you're targetting and see how it looks!

At some point, you have to adjust the corals to the flow. So those dead/low flow spots you're talking about - put mushrooms and stuff there. Or flow-sensitive euphyllia. My euphyllia seem to do the best with as little flow as possible.

Be careful adding pumps - water movement is a weird thing. Sometimes adding another pump that creates a bunch of random flow behaves very unpredictably and can create deadspots or make things worse. They key is to get a LOT of water moving consistently. Adding random pumps pointing all sorts of directions doesn't always accomplish that...



I also am a huge fan of the standing wave. It moves literally every molecule of water in the tank! It's also super awesome aesthetically. Agree with what Thomas is saying here too, the easiest way to get good flow is to get big gyre's moving and/or apply a standing wave. The latter is pretty easy to achieve too, I use a $65 jebao pump on one end to make the wave, and a single xf350 on the other end to get the gyre moving. No other pumps in my 6ft tank besides these two. Very, very simple. And I have mega flow.

Thanks, you've given me a lot to consider. I've been watching the sps closely to see if their polyps start coming out again.

I'm not sure how long it typically takes to get the regular Polyps to extend again when they are given the proper flow.

Is sps extending polyps something that should occur in a day or two, or is this something I should only expect to see in the longer term?

I'm envsioning using their polyp extension as a scale to judge if they're happy and receiving proper flow.

And using a torch as a test, do you mean just hold it in my hand in various areas to see the flow patterns? You used the phrase, "drop it in different places" I'm assuming you don’t mean leave it near the sps where it could sting them?

I will heed your advice and allow more time for observation before commiting adding the 3rd pump back.
 
Thanks, you've given me a lot to consider. I've been watching the sps closely to see if their polyps start coming out again.

I'm not sure how long it typically takes to get the regular Polyps to extend again when they are given the proper flow.

Is sps extending polyps something that should occur in a day or two, or is this something I should only expect to see in the longer term?

I'm envsioning using their polyp extension as a scale to judge if they're happy and receiving proper flow.

And using a torch as a test, do you mean just hold it in my hand in various areas to see the flow patterns? You used the phrase, "drop it in different places" I'm assuming you don’t mean leave it near the sps where it could sting them?

I will heed your advice and allow more time for observation before commiting adding the 3rd pump back.

In my experience, some acros take many weeks to get comfortable enough to fully extend their polyps. Some respond very quickly, like within hours. It could also be that flow is not your problem here at all...though getting flow right is still certainly worthwhile. And fun :)

I agree with @RandyC in that flow is just as important as light, maybe more so, my reasons for thinking this:
  1. I have a frag rack in my sump - exact same light (and of course exact same water) but with considerably less flow than my DT. LPS and softies love it there, SPS are fine but do not really grow much.
  2. Flow has by FAR the biggest/most immediate impact on alk consumption when adjusted (using twice-daily automated alk testing).
  3. When making major changes to my workwork recently, some SPS went from 350+ PAR down to about 150-200 PAR, and are growing just as well and have great color. The ones that aren't as happy as before are...spoiler alert...the ones that aren't getting as much flow as they used to.
Re: the torch, I just mean use the torch as a visual indicator in spots where you can't really see the flow. Don't sting anything, of course.

One thing to consider with flow is the return path of the water - that's probably the most important consideration with placement. Rarely do we place a pump to hit something directly, it's more about shaping the gentle indirect flow as the water moves elsewhere in the tank to replace what the pump is pushing. Rock formations and tank glass can force this return flow into hot spots or make it more gentle, depending on where the pump is placed. Placing it in the middle of a wall allows return flow down both sides, placing it next to a wall forces the return flow along the opposite side. Placing pumps up high creates more return flow down low, and so on.
 
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