MAG9 + Plumbing Qs URGENT HELP!!!

[xexxxe]

Hi, I am a newbi trying to set up a 75G tank with 30G Sump...

This is what I have so far...

1. 75G reefready tank with 1" to sump and 3/4" return overflow built in...

2. I have purchased MAG 9.5 for return pump.

with about 4.5ft of head... MAG 9.5 should have 800gph... and it seems like i have too much power on return...

I am currently hooked up with hose for all plumbing... 1" to sump and 3/4" return and I have a bad feeling it will overflow the tank when i go to sleep... so i decided to umplug the system...

is MAG9 too much for my setup? should i reduce the return(how?)

I got the oceanic 75G RR... and I saw it somewhere that the overflow is MAX 800gph...

should i change it to PVC pipe for plumbing? if so... what size?(inner diameter/outter?)

would valves for piping slow down the return GPH? will it affect the pump.... or should I just get MAG7...

I don't know what to do... plz help...

if anyof you have any good way to set up plumbing plz help...

THANK YOU for LOOKING

[Newflee]

If your drain or overflow line is 1" then you should be fine but the size and the height of the prefilter can also be a limiting factor. 900 GPH is not a lot for even small tanks so I suspect you should be fine. You could put a valve in between the pump and the tank and throttle it back a bit untill you can observe the performance more closely. However you should know within minutes if it is ok. It will either be fine or it will start to get too close to the top of your tank right away.It won't change overnight. Most tanks with high return flow see the water level a couple cm (@1/2") above the prefilter edge. Also make sure that the water is not being restricted by dirty prefilter floss or poorly designed standpipe etc.
Just keep in mind that you always place valves on the discharge end of the pump and not the suction side.

PVC wont help and in fact are less efficient than flexible pipes as long as your comparing the same ID. Clear flex tubing can get restricted with algae over time though. White PVC "spaflex" is ideal in that it is flexible, mates with standard PVC fittings and will not grow algae due to light penetration.

Don't get the smaller pump unless you absolutely have to. You'll be sorry later on. In fact if your tank is designed for a max flow of 700 GPH it is hardly what I would call reef ready.

[xexxxe]

am i worry too much about the tank level? is this normal? or am i just getting too much flow...?

would this help?

[swclown]

yes,
that will help. the return drain with ball valve you have right above the pump that returns water where it was just pumped from will cut the flow to about 1/2 with the valve fully open. as well, because there is no restriction on the pump it won't damage the motor at all

[Newflee]

Your new design will help cut down the flow for sure but that is something that few of us strive for. I think your idea of drilling a larger drain hole is a better option by itself. Also if your water level on your overflow is as you illistrated then you have no problem. It does ride higher than normal but if it doesn't get your carpet wet, it works.
I personally think those slotted overflows look fancy but are inferior to egg crate. That is why your water is running higher than expected. The slotted types restrict flow too much and must be observed for clogging all the time. I bet if you used egg crate for your overflow screen you would ride less than an inch over yout overflow even at 1500 GPH.

I would also rather have my return line at the opposite end of the tank. You could reduce flow somewhat by T'ing your return off with a return going to either side of the tank.

[BeanAnimal]

flex pipe has a higher flow rate than ridgid? NOT in any reality that I know. You will however be able to create less pronounced "elbows" to make things more even.]

Bean

[Newflee]

That's the point.
Given the same I.D., flex allows you to reduce loss due to sharp corners. I don't know what "Reality" your at. perhaps you should look at the whole question rather than extracting a 8 word phrase from a post.
What exactly do you mean by "to make things more even"? Now that's a plumbing phrase I've never heard.

[BeanAnimal]

Yes but givin the same ID, flex creates a considerably longer pipe run due to it's swept corners and general shape. This pretty much negates any gains made by reducing the sharp corners.

Add these losses to the reduced flow in flexible pipe and there is no net gain. In most cases, all other things being the same, there is a net loss.l

My statement was simply to point out that the losses of each tend to cancel each other out... still leaning towards rigid pipe as the overall flow winner.

Bill