misconceptions of flow and water movement

[brad65ford]

Hey guys, I can honestly admit this is one of the hardest subjects for me to comprehend since its hard to know what is making the corals (sps's in this case) happy. We have already read about sps's need high flow, so you my head i crank up the flow and wonder why they don't do well.

So what is really the answer? It seems to be a complex ratio between lighting intensity and nutrients along with water flow. At the moment I'm running a very small system (20g long with 10g sump). My over flow pump is 800gph which has been cut in half since its blowing like a mother. Also was running a MP10 at 4 bars (blue lights). For some reason it seems to be to much. Can anyone share their success by decreasing flow in their systems? Hopefully this is something more common and or thought wrong in the past. I'm going to cut the mp10 off and run the main pump at 1/4 to see if the corals will extend their polyps out more.

 

[Jettareefer]

I am by no means an expert I have experienced better growth and patterns with indirect flow with strong surges. I use a mp40 at 60% on a constant speed with a sea swirl on my 700gph return on a 58 gallon. Basically there always flow but every rotation of the sea swirl hits the coral and makes the polyps dance hard but no enough to make them retract this keep debris from settling on them as well. I use just aim multiple big powerheads and a stationary return in direction of corals with lukewarm results with dead spots throughout the tank. I only have 44x turn over some would consider this low I believe you just have to utilize your flow to make it as effective as possible.HTH

 

[M Woodhill]

My sps really look bad when I ran only 2 mp10 on the system. After I added an mp40, all became happier

 

[Tweaked]

Running a ton of indirect flow myself, actually a bit overkill, but the bb and sps dominant scape calls for it. I get the best results when the polyps are dancing and being crashed with waves from all sides. I run 3 40s in a 105 and I am now adding 10s to help with additional flow.

 

[glaukos]

Great subject brad

I always found hard too,setting up the best flow for sps.
Never had a permanent/favorite type or pump mode.
Especially when they grow big things are more difficult.
Always playing around with flow or adding pumps

In my humble opinion the best is strong random flow.
Strong one sided flow affected corals morphology/growth pattern,or in other cases,pealed off coral's which were getting that type of flow(if it was too strong).

Just my 02 cents

 

[rovster]

I don't think you can have too much flow. Talk about overkill, in my 30 gallon nano I have a wp25 long pulse 100%, mp10 reefcrest 100%, 2 koralia nanos, a larger koralia, and a hob skimmer and hob filter and I could probable use more. The lack of polyp extension is not from too much flow, unless the corals are right in front of the powerhead. Even then, some like that as well.

 

[Tweaked]

I don't think you can have too much flow. Talk about overkill, in my 30 gallon nano I have a wp25 long pulse 100%, mp10 reefcrest 100%, 2 koralia nanos, a larger koralia, and a hob skimmer and hob filter and I could probable use more. The lack of polyp extension is not from too much flow, unless the corals are right in front of the powerhead. Even then, some like that as well.

:thumbsup: ..and here I thought I was nuts. My fellow reefers come by and poke fun at all the mp's I run in such a small box, but my PE is amazing.

 

[das75]

high flow is not blasting your corals by pointing a wave maker at them but what you've picked up on, "water movement". Random and lots of it is what you want.

 

[a.browning]

I agree with the general comments so far. When I first got into SPS, I literally pointed a Koralia 750 directly at my sps and thought that's what high flow meant for SPS. I think it's all about random surges from all sides, but not a constant blasting either. I'm running 2 MP40s on my 75 but really feel like I need a MP10 on the back wall to get better flow. Even with the MP40s it's not as random as I would like, and there are still dead zones. I'm right at 100x turnover and really need to add more. I don't think you can have too much overall water movement, but you can have too strong of direct flow from a single pump.

 

[brad65ford]

Thanks guys for all your comments and I totally agree especially with larger tanks much over then mine little nano. IMO once you're 20g and smaller it becomes weird/different since you can't really create currents which sps's love do to the small square box restrictions. My sps's are mostly monti's, birds nests, pocillopora, stylophora a few different acro's. Last night I shut down MP10 so now we are just running the sump pump for water movement. So far there is a big difference in just a days time, plyop extension on the sunset monti is almost twice the size, birds nests are much better as well. As other nano sps owners have experienced its tricky trying to get the flow just right on this small of a tank. I'm now realizing why I had so many issues with my last BB 16g nuvo system.

Moving forward I will try to control myself and not turn back on the MP10 since we really need to test this for a few days. Not sure what the main goal is beside good color and growth, always wonder if plyop extensions is the answer to health corals.

Thanks again guys.

Brad

 

[DiscusHeckel]

I hope these articles dispel some of the misconceptions on water flow:

Water flow is more important for corals than light. Part 1. Introduction to Gas Exchange by Jake Adams

Water flow is more important for corals than light. Part II: The science of corals and water flow by Jake Adams

Water flow is more important for corals, Part III by Jake Adams

Water Flow is More Important for Corals Than Light Part 4: Basics of Hydrodynamicsby Jake Adams

Water Flow is More Important for Corals Than Light, Part V by Jake Adams

 

[Reefer54]

i think there is enough above about flow to get the points across. But there are also results that water stability surpasses even flow. If your water parameters fluctuate too much for certain corals, they will never do well. Having ultra stable Alk, SG, Temp, are huge for sps. A tank with all the appropriate flow in the world but fluctuating paramters wont compare in growth and health to a tank with half the flow thats not as optimal but has stable water.

i only say this because i see your tank is a 20g tank. It is just not a small chore to keep that volume tank consistantly stable, minor fluctuations are not a big deal for the most part (depending on your definition of minor) but with minor fluctuations in all those parameters plus others occuring frequently, that can be enough.

and of course i dont know these specifics with your tank nor am i saying that is the case....just that it is a definite possiblity to be considered.

good luck, have fun

 

[brad65ford]

i think there is enough above about flow to get the points across. But there are also results that water stability surpasses even flow. If your water parameters fluctuate too much for certain corals, they will never do well. Having ultra stable Alk, SG, Temp, are huge for sps. A tank with all the appropriate flow in the world but fluctuating paramters wont compare in growth and health to a tank with half the flow thats not as optimal but has stable water.

i only say this because i see your tank is a 20g tank. It is just not a small chore to keep that volume tank consistantly stable, minor fluctuations are not a big deal for the most part (depending on your definition of minor) but with minor fluctuations in all those parameters plus others occuring frequently, that can be enough.

and of course i dont know these specifics with your tank nor am i saying that is the case....just that it is a definite possiblity to be considered.

good luck, have fun

Totally following you, honestly the lack of stability isn't my main issue (been down this road many many times and have had great success before) if anything being to premature on age of the tank would be my first concern. Pushing 2 months yesterday :celeb2: But already have Coraline growing on the dry rock and elk horn frags growing out and attaching from the base. Hate waiting in this hobby but its part of the game. Have a feeling in a few months i'll be turning up the flow but for now all the corals don't like the MP10 even at its lowest setting. A nice gentle flow is what they seem to like right now.