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Discussion Starter · #1 ·
I am designing a CLS for a 360 Gal acrylic tank (8'Lx24Wx36H)

I have purchased a Barracuda pump with 1.5" inlet and outlet.

After bends, valves and bulkheads, the return will end up in spray bars along the back. Based on pipe cross-sectional area, 1.5" = (2x1")=(4x3/4")=(8x1/2") =(16x3/8") = about (32x1/4") (these are rounded approximations)

So if my spray bars have 16 x 3/8" holes, the velocity through them will be about the same as the velocity out of the pump.

Pump out put = 3750 GPH - in the 1.5" pipe. Using an online calculator I get a velocity of about 11 ft/sec. 11 ft/sec from a 3/8 " hole seems too strong to me. If I double the holes, I can cut the velocity in half.

Q1) What is a recommended range of velocity out of a spray bar?

Q2) Are my calculations and assumptions correct?

Q3) is a 3/8" hole normally used in a spray bar?

Thank you,

Dave
 

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I have a spray bar I the back of my 300 gal tank with about 5/16" holes running along the bar every inch of a 6 foot bar. The pump is 5800 gph. I have the return also feeding other areas of the tank but the velocity of the spray bar has never been an issue.
 

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You could start out with smaller diameter holes in your spray bay...say 1/4"....fire her up and try it. Adjust drill accordingly. You could put a gate valve on the spray bar and regulate the flow also.
 

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i prefer to use eductors on my CLS's instead of sheer flow. they require a totally different kind of pump, high pressure. i use high volume pumps for clearing specific areas. i had a Ampmaster 3700 blowing out through 2 outlets directly above my epoxy sand bed in order to keep the undersides of my LR structure completely clear of detritus. they were only 1" above the epoxy bed. the velocity was not a problem. in fact i liked that much. it allowed a back flow out of the LR structure to keep the corals clean from below.

read up on eductors. i have a few DIY's of some.

G~
 

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Discussion Starter · #5 ·
i prefer to use eductors on my CLS's instead of sheer flow. they require a totally different kind of pump, high pressure. i use high volume pumps for clearing specific areas. i had a Ampmaster 3700 blowing out through 2 outlets directly above my epoxy sand bed in order to keep the undersides of my LR structure completely clear of detritus. they were only 1" above the epoxy bed. the velocity was not a problem. in fact i liked that much. it allowed a back flow out of the LR structure to keep the corals clean from below.

read up on eductors. i have a few DIY's of some.

G~
I already have read up on the eductors and do plan to use them in my sump return. My sump return pump is an Iwata 70 which is better able to handle head/back-pressure. I am planning to have (4) 1/2" Eductors along one end flowing lengthwise along the faux bottom, under the LR which will be on risers. My only concern is the possibility of a back siphon. I am currently planning to install 2 flapper style check valves in the return. I am also considering to loop the piping up above the DT water level, drill a vent hole pointing up, and install a check valve that would be closed under pressure, but vent air in under suction.

The CLS return will be an array of spray bars along the back with (4) squids changing which ones flow at any given time.

I hope to have most of the detritus flow into the sump for separation and removal. I also have a couple wave master pumps which I hope add later to steer/drive any remaining sand/detritus toward a single accumulation point for easy extraction. (with some luck)

What do you think?

Dave
 

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The CLS return will be an array of spray bars along the back with (4) squids changing which ones flow at any given time.
I'm not a huge fan of spray bars myself, I have used them, but found a good pump with eductors can not only keep the detritus suspended, but also keep your corals happy with flow. they also limit a lot of dead spots that you can get with spray bars.
 

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flapper style check valves are a bad idea in a reef tank. they will quickly become clogged with calcium and other critter deposits, limiting their ability to work. if you still do decide to go the check valve route make sure the ones you get, do not use metal springs, or if they do use metal, make sure that they are titanium or monel.

i would just skip this and just use a CLS for any below line flow. the risk of back siphon is just to great.

did you look at my build thread? linked in my sig. if you can plan out your LR structure from the beginning, then creating a large CLS using the Barracuda to allow decent amount of flow from within the LR structure would be your best bet. i think that flow to the bases of corals is the biggest problem that is not addressed. in nature those huge massive waves push through the entire reef structure. this is hard to emulate in our boxes. we are trying to power the flow through the coral growth. i think that we should be trying to create outward flow from the LR in order to give the coral bases some extra flow to help with waste export. this along with helping the LR expel phosphates from its structure.

G~
 

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Discussion Starter · #8 ·
did you look at my build thread? linked in my sig. if you can plan out your LR structure from the beginning, then creating a large CLS using the Barracuda to allow decent amount of flow from within the LR structure would be your best bet.
G~
I read it a in february. i will read through it again.
 

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Discussion Starter · #9 ·
if you still do decide to go the check valve route make sure the ones you get, do not use metal springs, or if they do use metal, make sure that they are titanium or monel.

G~
On a separate line of thought, we have discussed in a few different threads the use of settling tanks and concentrating detritus for easy removal. I have found an interesting sediment filter, but the inner screen is stainless steel. (I believe 316ss) I know this will slowly corrode in salt water and release some heavy metals (Iron, Nickel, Chromium and a little Molybdenum) over time. I am wondering if GFO, Carbon, skimmers, or some other material might be able to remove heavy metals?

The link below is a video of the filter I like. I am checking with the manufacturer to verify type of stainless and to see if another material is available. In the video, they compare the product to another centrifugal separator that is available. They have non metallic screens available, but are not set up for back flushing.

http://www.twistiiclean.com/videos/T2C_Filter-Comparison-Audio-HD.mp4
 

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i saw that style centrifugal separator. i would also be cautious about metal in the system unless it was titanium.

at the time i was getting a settling tank i did not know about these, so i just got the old fashioned conical style. mine is only a 30g, they come in 60g and larger for bigger tanks. depending on the size my new system becomes i may need to go with a 60 or larger also.

G~
 

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Discussion Starter · #11 ·
i saw that style centrifugal separator. i would also be cautious about metal in the system unless it was titanium.

at the time i was getting a settling tank i did not know about these, so i just got the old fashioned conical style. mine is only a 30g, they come in 60g and larger for bigger tanks. depending on the size my new system becomes i may need to go with a 60 or larger also.

G~
But my house is one story on a slab, so my sump and whatever equipment will be housed under the tank. I found a 10 gal bottom drain tank, but it is rectangular. the cheaper version is available with a poly mesh. I am considering to do a fancy plumbing job which would allow me to occasionally backflush it.

In 6 months or so, After I am better set up. I may buy filter with the stainless screen and set it up on a hospital tank and let it run. Then I can take water samples and test for any metal pickup, without any critters involved, and no live rock to absorb it.

do you know anyway or where to get a screen titanium plated??

Dave
 

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if you have the extra money, it might be a nice tool to play with, but i am not sure it would be more efficient at removing detritus then just putting the biggest sump you can get below the tank and putting the least amount of flow through the sump. the centrifuge might be smaller, but i am not sure that having the extra volume from the sump would not be a bonus over the centrifuge device.

G~
 
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