Discussion of the Week =Waterflows and designs for reef tank

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mojoreef

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Ok time for a new topic. As requested the new topic will be on water flow needs and designs for use in our reeftanks. This should be a great topic and lots of folks should be ablle to participate, Soooo lets get it going


Mike
 
defacto standards

My understanding is that water flow should be ten times the volume per hour. This means the volume of the tank should be replenished every six minutes. I personally shoot for a little higher and lower the input flowrate to get the desired effect. The one inch drain is also consider optimal. Again, I use a larger one and a half inch drain. I also use three-quarter inch returns. I use the lager drain because I could not put a secondary drain in, due to space constraints.
 
so if you have a 55 gallon tank which is probably 35 gallons at the most water volume with a DSB then 35 x 10 = 350 gallons an hour? i'm at probably close to 1000 gallons per hour in my tank. i have 2 maxi-jet 1200's at 295 gph, another powerhead at 250 then my return which is probably 150 - 200gph.

i thought that i was still probably in the low arena for having most corals.
 
flow rate for the sump

This is a standard for the return of the sump water. The corals that you keep have specific needs of water movement unrelated to volume turnover rates. Each specific coral has adapted to a flow rate from the area that it grew. I believe this is why frag's do better than colonies. The additional flow of water around the coral must be made up by additional powerheads. The exact amount is probably unknowable, empirical evidence should be your guide. A general rule of thumb is that hard corals need more water flow and soft corals need less. Beyond that whatever works is the best solution.
 
Discussion of the Week - Water flow

What is the maximum amount of water flow one should have, or is there one?
I have a 30 gallon tank with 1 - Maxi-Jet 1200, one RIO 600, and a fluval 304 closed halfway to slow the amount of current in the tank. I estimate around 600 GPH, is this too much? I am not conting the CPR skimmer I have either; this is run with a RIO 600, and the amount of flow coming out of the skimmer is very small.

Also, does anyone have any opinions about slowing down the water movement during the night? I read that it is a good idea to slow down the water current down near the bottom of the tank as to simulate the slower the nighttime ocean currents, so I have my RIO 600 shut off during the night as it is the one which shoots across the bottom backside of the tank.

Eliyah
 
Flow is actually alot more important then most folks give it credit for. One of the main concepts of flow is to keep corals and such clean. When detritus lands on a coral and is not removed it will be attacked by bacteria to reduce it. This can and will lead to bacterial infections and will cuase unneeded stress on the corals. Also flow is required to keep detritus in the water column thus making it available to critter that my need it for food and to get it out and to your export system (skimer and so on).
The standard rate of x times per gallons is at best a loose reference point, but I really believe we must go alot farther on it design and purpose. I also feel that we must seperate the 2 types of flow our tanks recieve. One type is that of the return water from our processing stations (sump/refugiums/skimmers and so on). For me this is not to important beyond making sure that we are processing the water at a good rate, It is part of the over all flow in the tank but becuase of restrictions with how quickly we can use a sump with out creating micro bubbles, or the various contact times needed for use with refugium, macro algae, remote beds. The majority of the water flow will come from power heads/closed loops and so on.
So for sake of a good conversation lets dump the sump/refugium return and concentrate the dynamics required in the main tank itself.

mike
 
Eliyah its tough to recreate water flows on a reef. They are estimated to between 30 and 50 thousand gallons an hour :D The main thing you need to look at is the corals that you are keeping, every coral has its own needs and requirements. Also with the release of toxins from corals we need to flow them out of the tank also. I have read about the lower flows at night but I believe this will only count when we get close to natural water flows rates.

aquariumdebacle sorry I just realized that I repeated most of what u said.

Matt in my tank according to the standard measure I shoould run around 7000 gph. Well I run at around 35000 gph, so its not really good guide line.

So what is a good guide line.


MIke
 
i have noticed that quite a bit of people have plumbing issues, which have a lot to do with flow problems

one thing to remember is that the more bends (elbows) that you have will cause less flow (higher headpressure), so the less bends that you have the better off you will be
i also see a lot of people using flexible PVC, which is a great idea for those odd bends, but this also causes head pressure
another thing to think about is when buying ballvalves (which i recomend for cleaning and replacement) is to get free flowing valves, basic valves restrict flow, ie headpressure
the point is when buying a pump keep this in mind, you might have to get a larger pump than you thought because of the head pressure

one thing that i have done is to take the 1" PVC (for my return) and actually bend it to go arround the top of the tank so i didnt have to use elbows(my tank isnt drilled), and in other places i used 2 45deg's to make the bends easier on the pump, so the pipe is at angles instead of making hard turns to end up in different spots in the tank, this has saved me some money and headpressure i have about a 10.5-11 foot head w/o any bends and with the bends that i have i think it is around 15 foot +/-

another thing that i will be using, when i get a chance to get, is a SQWD which is a very cool device which helps to mimic the natural movement of the ocean, and which IMO are great with closed loop systems

ok, i will shut up now :)

TD
 
Re: currents and flow

I'd like to take a tangential track here. Laminar flow is fine as it goes, but we are keeping creatures which normally experience turbulence, surge and a rise and fall in the water column. I've been particularly interested in the means people have come up with for generating various currents in their setups. For example, the Monterey Bay Aquarium is famous for its discovery of the current requirements of giant kelp for the lifting and falling motion provided by wave action, which they simulate with a giant lift / displacement pump. I've started seeing rotating dual-nozzle outlets in reef tanks and I was particulary intrigued by the web page of Robert Michelson http://avdil.gtri.gatech.edu/RCM/RCM/Aquarium/CirculationSystem.html where he shows a number of current generators he has built. I'd like to take this one step further and incorporate the randomness provided by the so-called "three-body problem" of physics, which would give me a completely random surface disturbance.
 
Neat link onthereef and I totally agree with you on the creation of turbulant flow. Laminar flow allows pockets of detritus to form opposite of the direction of the flow. On my tank I used motorized ball valve and loc line to recreate wave action followed by slack flow. this happens in four different sections of the tank at any given time.
Tdevil your dead on head pressure is greatly reduced by all the elbows and tees and so on that are used in a tanks plumbing.

One thing that has not been used very often in our tanks but is really popular in the aquaculture industry are eductors. They are a simple plumbing fixture that costs about 20 bucks. They will basically increase thier input by five times...so say 1000 gph going in you get 5000 going out. You can even home make them for a couple of dollars.

Mike
 
*Thanks for the input Mike, I was also researching those eductors which look like something worth trying. Has anyone here ever tried one of these out, and if so did they install it on a return pipe or a Power Head?

Here is the link to a site selling these for aquariums that I found if anyone is interested:
http://www.emperoraquatics.com/new-commeductors.html

*OnTheReef, wouldn't using a SQUID setup on a closed loop system be the same as the setup in that link you posted? I was under the impression that the valve in the SQUID did something similar to this, allowing for the water to pass through one side for a period of time, then the other. I'm curious because I was planning on using one of these for my next system.

Eliyah
 
SQUID

I used to have a SQWD on a close loop on my 25g HI. The flow is really nice and I really love it. But when I move to 50g. The flow isn't that strong anymore. The switch from one nozzle to another is too fast I guess for a 50 gallon.

So instead of buying a more powerful pump to be used for SQWD. I just made a DIY sea swirl made out of cheap 7 dollar garden/lawn springkler system attached to my pump from sump.

This didn't create the flow because i don't have enough pressure to make the water move but enough to make it sway 90 degrees...

Then I just attached two powerheads to it and there you go...

here is a sample pic...

diy_seaswirl01.jpg


Did anybody ever tried this before.
 
Using GPH as a standard to determine if there is "enough" water flow, be it laminar or not, seems to be very missleading. I suppose this form of measurement could be used to establish relative standards to meet some of the goals of water movement as stated in prior posts. Such as keeping detritus and food suspended in the water column.

With that said, how can comparisons be made from the volume of water movement created by a jet of water being pushed by our pumps to the huge volume of water moving in the oceans.

What is the typical velocity of water movement at different parts of a reef(front,back crest). Shouldn't we be more concerned in trying to reproduce the velocity and volume of concurrent water movement in our tanks.

How important is water flow when considering its role in SPS coral growth rate and formation. I have seen different frags in different tanks grow into different shapes and rates. Also is it known if water flow pays a part in polyp extension?
 
Great posts folks.
Eliyah I have a bunch on my tank, and I really like them. what a cheap and easy way to multiply your flow rate by 5. they have a 3/4 inch male thread on them. The end of them is fluted and puts out a wide flow pattern. On my tank the create a small sunami. remember you can also make a DIY model, for pennies out f stock pvc fittings to.

Katchupoy another neat idea.

Slow boat I agree. In regards to polyp extention, dont put to much concideration on that. A SPS uses it polyp for many different things repoduction/offence/defence/light gathering and so on.

Ok on flow. this is the way I look at it. when I have designed tanks I do it with the filtration method in concideration. So here would be a plan for a tank with out a dsb. The concept of flow in this type of tank should be to keep the detritus in the column and directed to the overflows. I usually make sure that some type of a spray bar is used, on my current tank I powered it with the return pump from the sump. Spray bars have one purpose and that is to make sure detritus does not collect behind or under the rocks. You can build a spray bar by doing a standard pipe behind the rocks with holes drilled in it. Or you can make it a bit more trick by building a rock rack (to suspend the rock above the bottom of the tank) then simply attach a water power source to it and drill holes into it.
This spray bar/rack will create a flow pattern pushing from the lower back out to the front of the tank. I always make sure that I have flow sweeping the ends of the tank and sweeping the water from the back side s to the front also. From thier I take more inputs and direct them down from the top back to the lower front. This combination creates a flow that goes from the lower back to lower front and then up to the top of the tank and then back to the upper back overflows.
The main thingn for flow is to mak sure you dont have any open dead spots for flow, all areas have flow. How much flow?? as much as you can wih our harming the corals tissue. From here you can try to install equipment to make it random.
Sources of random are sea swirls, squids, 3 way motorized ball valves, or standard 2 way valves. Pit falls of the above are that the sea swirls are very delicate and tend to break the linkage easy. Squids tend to get calcified quickly, motorized ball valves are great but are expensive. 2 way motorized ball valves are not as expensive (about a 100 bucks a peice) and do just as good. from here thier are a host of DIY projects, some as listed above.

MIke
 
Re: SQUID

Katchupoy said:
So instead of buying a more powerful pump to be used for SQWD. I just made a DIY sea swirl made out of cheap 7 dollar garden/lawn springkler system attached to my pump from sump.

This didn't create the flow because i don't have enough pressure to make the water move but enough to make it sway 90 degrees...

Did anybody ever tried this before.

That is a great idea I was looking at sprinkler heads last weekend thinking how I could try to use one in my tank.

Which style do you use? And do you have to MOD it or gut it in any wait?

mojoreef said:
Squids tend to get calcified quickly, motorized ball valves are great but are expensive. 2 way motorized ball valves are not as expensive (about a 100 bucks a peice) and do just as good. from here thier are a host of DIY projects, some as listed above.

MIke

Has anyone ever used Lime-away or is there a similar product that can be used to reuse and/or recycle these by removing built up calcium. (sorry I am not a veteran to SW)
 
White household vinegar works great on removing buildup of calcium on pumps, heaters, etc.. For maintenance I normally soak impellers in vinegar for a couple of hours and then take a tooth brush to them. Afterwards a good rinse in water.
 
Are there any local scuba divers around that are willing to do some testing of the water velocity.

Any ideas on a device that could be used to determine velocity? I am thinking something that can measure the angle of deflection.
 
OIC!

Cesar,

I was actually thinking about those pop-up style sprinklers that when that water turns off the head retracts.

Your idea is a million times better... :oops:
 
Awesome DIY, I was thinking of the old Hunter Reef Rotors, that looks better
I have toyed with something similar using an old windshield wiper moter and mechanism to drive it :), OICT
 

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