please help double check before i drill and make a mistake

[kau_cinta_ku]

ok first off let me say sorry for the bad drawings as i did them at work last night.
this whole seting up a new tank is very fun but also very confusing to get everything setup the way you want it so i will try to explain the best i can. and once again sorry for all the questions.

ok so after alot of reading and such i have decided i love the Anthony Calfo style CL and went with that. so here are my plans. this first pic. is of a 75 gal tank that isn't drilled "YET" i got a 60mm diamond drill that i am gonna put 1 1/2 bulkheads into the tank. this will show where i plan to put the holes as for building my own overflow i would like the lower left bulkhead to be as much in the corner as possiable so i am now thinking the center of the hole will be 4'' x 4'' from the edge of the glass will that be fine or should i leave a little more room.? as for the CL intake i think it should be good there as it will be high enough to be asy to reach and clean but low enough so it can be hidden behind the rocks.
http://i13.photobucket.com/albums/a296/kau_cinta_ku/75gal.jpg

this second pic. is of the CL that will sit around the top of my tank but i am still way confused on what size PVC to go with that that is where i am gonna need the most help.
http://i13.photobucket.com/albums/a296/kau_cinta_ku/cl.jpg
so all in all i just would like any ideas or changes that could be made to make this whole thing run better in the long run. before i actually start to fill it. thanks very much for all the help you guys/gals can give me as this is my first time setting up this big of tank and doing all i can to it DIY style.

[Jiddy]

The design is good, but in my opinion, which Travis knows better, you will need a big pump to push that, i have 4 outlets on my Mag12 and its not really that nice. So you will need a bigger pump AT LEAST 2400 gallon one, and if you get a pump that big, the 3/4in PVC will be to small and restricing for a pump that big. I went with 1" because the wife didnt want 1 1/2 in piping. You could always do what i had, and go with 2 smaller sq. manifolds too

[kau_cinta_ku]

so maybe a mag 24 or 36 using 1'' pvc and 3/4 ball joints?or if anything i can always cap a few if there is to much flow in some areas

[Jiddy]

What do you want to keep?

[kau_cinta_ku]

i would like to keep most anything except for the hard sps for now till i get more experence behind me.

[Travis]

Jiddy is right. With that many outlets, you are distributing the flow evenly across each outlet, assuming each outlet gets the same amount of flow (which isn't the case, BTW). So even if you were to run a Mag 36 on that sucker and it is plumbed with 1.5" all the way to each outlet you are still only going to be getting roughly 400 gph out of each of those outlets. That may be ok if you use loc-line on each outlet. The loc-line will reduce the output size, which in turn will reduce the amount of flow but will increase the velocity of the flow. Lets say you left each outlet 1.5". You will have about 300+ gph coming out of each 1.5" outlet, which will give you almost stagnant flow because 300 gph is not enough flow coming out of that big of pipe to create good enough velocity. So you will have lots of flow but your tank will look like there is almost no flow at all. Now let's say you put 1/2" loc-line on each outlet. The loc-line is going to put back pressure on the pump so lets say (and this is just a guess for the analogy) you are getting 200 gph out of each 1/2" outlet. The total flow will be less but you will have velocity, which will create the needed flow in the tank. Another way to look at is is go outside and turn on the garden hose full blast. There will be a good amount of water coming out but it has little velocity. Now put your thumb over the output and you get some major velocity. Now that velocity inside your tank will cause the water to keep moving for longer and will also cause the water around it to also move. You need to balance everything so you get decent velocity (not too much) and still have decent flow (because you didn't overrestrict the outlet). All said and done, I would say don't go anything smaller than a Mag 36. You can always dial it back if it is too much, but I highly doubt that will be the problem.

[Travis]

Your bulkhead locations look good. Make sure you know the dimensions of the bulkhead you will be using. You want to know how wide it is to each end of the flange for the one you will be using for the overflow drain. As the flange and ring on the inside of the tank don't hit the wall you will be good to go. I would drill as close to the bottom as you can, while still having room for the bulkhead. I guarantee you are going to run into a problem with detritus building up in your overflow since the drain will not be on the bottom. Actually, most people already deal with this anyways because they use durso standpipes. The lower the drain the better it will be at keeping detritus from accumulating. You will probably have to take a turkey baster every once in a while to stir up the bottom of the overflow to keep detritus from building up there and starting to break down and pollute the tank.

[kau_cinta_ku]

ok thanks for that great help. the was very interesting and i do understand what you mean by the back pressure but now lets say i run only 1 1/2 up to the top of the tank and use 3/4 or 1" pvc around the tank would that give me the back pressure i would need? and maybe only go with 6 outlets instead of 8 the reason i was gonna go with 8 would be so i could cap off a couple to start with and only run 6 of them at a time but having the 8 would alow me to cap 2 diff. ones depending on where i needed the flow so yes there would be 8 outlets around it but only 6 running at once.

as for the holes i will keep the overflow hole as close to the bottom with leaving enough room for the flange. at first when i thought and drew it up i didn't expect the bulkhead to be that big till i got it in the mail but i will make sure to leave just enough room.

just an update i took an old 10 gal tank to practice drilling the holes and they were so easy to do i was amazed didn't break the glass like i thought on that thin of glass.

[Jiddy]

Yea go with a maximum of 6 outlets, you can design it with 8 and just cap 2, that way if you test and its all good then you can leave uncap'd. I guess i dont know why you would want 4 outlets on one side, im assumin the front of the tank, two should be just fine, especially if you use locLine fan nozzle's.

The biggest design flaw with havin one sq CL manifold is leaving a gap for the overflow box itself. since i have two small CL's, i just have my box in the middle.

[Travis]

Heck, you may be fine using all 8. It is so hard to tell until you have it all plumbed and turn the pump on. I think keeping all 8 and leaving the option to cap a couple off is a good idea. The best way to plumb it would be 1.5" all the way to the manifold. Then start the manifold with a 1.5" tee that splits off into 2 3/4" or 1" sides (whichever you go with). Either one should be fine.

Personally, I don't think you will need that many outlets at the front. They will not do much for you because you don't want to blow the water directly on any corals. You want to bank it off the glass, cause it to collide with flow from other outlets, and cause it to move around the corals. Corals do not like being hit directly. The best place for the outlets is the sides. That way you can run the flow along the length of the tank and not direct it at any corals. A couple on the back will be good to bank off the front glass. On second thought, maybe a couple along the front will be ok and you can bank them off the back.