Aquarium Flow: High Flow versus Random Flow

[revhtree Verified Admin]

So I have been thinking a little more about aquarium flow as of late. I have seen a ton of discussion going on about the best power heads, water movers, return pumps, etc. and I thought we might get a good discussion going about your experience with water flow.

Personally I have enough water movers to make my tank look like a Jacuzzi if I wanted but that's not what were looking for. I began to to wonder if multiple water movers at a lower more random flow is better than a few at higher levels of flow. I hate moving/blowing sand, and I hate having to position different corals for various flow conditions.

So my first question to get this thread "flowing" is this.

Is optimal (good) water flow "high flow" or is it more "random flow?"

I think there may be more to the story so let me hear your thoughts on it.

<insert eye candy>

The 650l Reef Tank of Pawel Szember

 

[Mohammad D. ALMUTAIRI]

I'd go for Random
for me I have test low, Mid and High flow as I got a planted tank which can't handle the high flow
I tried the all kind of random flow into my tanks
I came up with my trust as mid random flow is one of the best way to deal with the tank "unless it's SPS"
as it doesn't hurt the fish not coral/plants
add to that it keep the bottom of the tank clean shooting everything into the overflow

that's just my 2cent on the matter

 

[Crabs McJones]

I'm going to say high random flow, best of both worlds. High flow for the sps, and random so that the corals don't get used to being blasted with high flow only from one direction or one way.

 

[DarthSimon]

I always think to duplicate the ocean, where our corals come from. I have dove many dive sites and can tell you, flow patterns down on reefs where the corals are dense and thriving are super random. You can get whipped around a reef while your diving..... We call it drift dives... Let the current take you.....

I would say Random for sure, and then take in account your coral species, which have flow requirements. Acros/SPS high flow, LPS and Softies like it calmer...

 

[Milkmanskid]

I always think to duplicate the ocean, where our corals come from. I have dove many dive sites and can tell you, flow patterns down on reefs where the corals are dense and thriving are super random. You can get whipped around a reef while your diving..... We call it drift dives... Let the current take you.....

I would say Random for sure, and then take in account your coral species, which have flow requirements. Acros/SPS high flow, LPS and Softies like it calmer...

What about mixed reefs? I can’t keep all mine as happy as I’d like them to be so because of the sps I have the water is a little more turbulent. The torches don’t mind but the frogspawns and hammers don’t care for it nearly as much. Everything else is fine so I leave it there. I’ve come to the conclusion that you can’t make them all happy. Oddly enough the other euphyllia’s still grow great. They just don’t come out as big as when there is slower flow.

 

[Scorpius]

Vortech Pumps in Reef Crest Random to around 2-3 clicks below full blast is what I run on my system. I use 4 mp10s on a 65 gal 3ft system. I have quite a few sps. Chalices do fine on the sand bed with all this flow.

 

[CalebWBrink2000]

I like mine to be random, but as high as my corals can stand it without getting upset. Fast flow does numerous great things in a reef- reduces detritus buildup, reduces algae growth, cleans off coral slime, etc.

 

[hart24601]

I am not really sure anyone has very high flow that isn't random. Does anyone that has grown large acro colonies really suggest pointing high powered powerheads directly at coral?

It seems that mostly very high flow is created by multiple powerheads and the flow created by multiple PH is random anyway.

I would say where it's tricky is mixed reefs. We get greedy, I want acros, and big brains, hammers, bubble coral and zoas with a clam! Now that is where flow get tricky IME. You have to compromise and realize that your setup might not be ideal for everything, but you make it work and that is generally a more random flow. Now you want 100% sps? Well that is naturally going to be different if you want to optimize the tank but not a single person I know means laminar flow blasting directly on coral when they say high flow.

 

[Adele]

You can get whipped around a reef while your diving..... We call it drift dives... Let the current take you.....

I experienced this for the first time snorkeling in Kuai, HI. You would get picked up by a current and next thing you know you are flying through the water then, just stop. It was an awesome feeling! thanks for the memory

 

[Adele]

+1 for Random and the intensity would be on what your corals thrive in. Certainly wouldn't want to put a chillin softie in a mosh pit, Stick flow.

 

[overclockwise]

I have a Tunze 6208 standing wave generator and two Jebao PP-15 on the sides setup to alternate a gyre every 15 min.

I'm not sure why no one uses standing wave generators anymore (maybe because of rimless tanks?) but softies, LPS and SPS seems happier vs when I just had the two pumps.

 

[Daniel@R2R Verified Admin]

Ugh! I hate putting those 2 against each other. I think that both are important. I'd go for as high as you can get it with random flow.

 

[cracker]

I ilke Lots of random flow as much as the corals will take. I'm experimenting with this now.

 

[Porpoise Hork]

I look at it as you want to recreate the flow characteristics as found in nature that the specific corals and fish you keep require. Depending on what part of the reef it is there may be laminar flow, random turbulent flow patterns or oscillating wave action. The challenge is most of us have a wide variety of fish and corals that have similar or vastly different needs, so recreating this for all of them is not easy. On this premise I configured the flow in my current tank to have two types of flow patterns. The primary flow is from a 306 canister filter that creates a near gyre flow pattern from the back right corner across the top of the tank to the front left. I placed a small 100gph pump with a fan tip on the opposite side of the tank near the top flowing from back to front across the surface. This provides a nice steady directional flow for all my torches that are on that side of the tank. To add random flow and to create the oscillating flow pattern I added a small dc wave maker on the right side about 2 inches down and 4 - 6 inches from the right rid of the tank , and it's directed straight at the front glass. This pump is set to cycle on/off every 30-45 seconds. The pulse it creates is stronger than the 306 flow and reverses the flow across the torches giving them the wave action they need, but also creates the randomized flow on the right side that my acans, hammers, and Frog spawns etc all do well with. Even my feather duster loves the pulsing action in that spot. I also have a little cove area where stuff like my bubble, blasto, and ricordea sit that is much lower flow. It took some time to get it all dialed in like this where everything is happy based on what it is and where I put it.

I'm expanding on this on my new tank with dual outputs on the return lines with fan tips and random flow nozzles, as well as much larger wave makers. So hopefully What I am doing will transfer well to the larger tank.

 

[Twolabs443]

"High" random flow certainly seems to be the go to answer more often then not, but I don't find that answer terribly descriptive to the concept people are trying to convey. What I think works best and most folks are after when calling something "high" flow is not high intensity/speed flow, but rather moving as much water volume as possible. I think this is why gyre flow generators are so popular and work so well. They aren't trying to necessarily create a single direct flow of water but rather trying to move as much volume as possible. The way I think about it in my head is that in nature a reef usually has a current that flows through. It might not be the fastest movement of water, but it is strong and powerful. Creating that kind of water movement in a reef tank system can be extremely challenging as powerheads often create too much of a directional blast of water that most coral don't appreciate when operating at high volumes.

 

[ca1ore]

high + random = chaotic. More chaotic ..... more better.

I don't really like the 'gyre' pumps as they tend to create laminar more than chaotic flow. Strong laminar flow (constant power-head pointed at a coral) is not a good thing.

 

[Susan Edwards]

I have 4 wave makers, all set to more of a fast pulse for random. If I try to do a surge with 2 I worry the waves will spill over the top! The 4 I have are all at 20-30 %, lots of surface movement and if not careful, lots of sand movement so I get lots of high flow areas.

 

[Gareth elliott]

I went with as simplistic as possible.
Right now have 1 wave maker on 60% surging every 90 seconds. On one side and the output of my return with a random flow generator nozzle set to about equal gph as the wavemaker. Keeps detritus suspended. As well as a wide flow pattern.
Total gph every 1.5 minutes is ~45x display volume.
I have another wavemaker on standby if this isn’t enough later.
Use the current loop system. If i was using an apex would do stronger surge on longer intervals.

 

[redfishbluefish]

My choice isn't in the poll.....I say both high and random flow is my vote.

After seeing a local reefers 180 fully stocked with stick colonies....with I believe 12 powerheads..YES, TWELVE.....and Dana Riddles MACNA talk from 2016, I increased my powerheads from two MP40's to four MP40's and an MP10....flow is the answer....and I'm considering adding more. Here are the powerhead locations in my five foot tank.

If you wish to just see the discussion on flow only from Dana, it starts at about minute 24:45

 

[Paul B]

You could not over circulate a tank. The best flow would end up with all your water on the floor and most wives frown on that. We can never replicate the flow of a coral reef or the randomness. But not all flow in the sea is random. In the South Pacific where I dove with moorish Idols there was very high flow but always in the same direction just as it is in the Cayman Islands. The flow, especially near the surface forces more oxygen into solution. It over saturates the water with oxygen and fish love that. Right at the edge of the sea and the rocky shore where the waves crash is loaded with fish. If I were a fish I would stay far from these places but fish seem to love those areas. Sharks and rays lay in troughs where the sea rushes through cuts in the rock.
There are very few life forms in stagnant water unless it is an accountant from Bayone New Jersey on vacation in his Speedo with his girlfriend from Wall street.
I even catch sea horses here in New York in very high flow estuaries which I don't really understand because seahorses are not exactly the tunas of the sea.
I keep my powerheads right near the surface which creates great flow and forces gases into the water. Of course it also forces the water to hit my lights and everything else.
Fish love that. I myself use this gas outboard for more flow. But I have to re fill the tank every 8 minutes or so.