[Reticentregret]

so i want a pump i found a good deal on that puts out 1270gph becuase i want to have 10x turn around.. no exceptions for that i want good flow.. but now im looking at a continuous siphon overflow that is rated for 1200 gph is that extra 70 gonna cause a flood problem of perhaps should i go with the 1400 but then is that gonna be a major flow problem as well? im confused i mean do the pump and overflow have to match perfectly if i have a small difference will the world end or something?

[ry77]

Might want to look into the head loss on that 1270goh pump. It's possible that in the distance it takes your return line to get back up to the tank you could lose 70gph or so.

[Reticentregret]

wow um thats confusing heh i didnt catch that

[ry77]

Headloss is pretty much the reduction of flow in a vertical pipe due to gravity because it pushes down with 13.7 psi which causes all kinds of cool stuff to happen, like causing your overflow to work. So basically even though the pump says 1270 gph depending on the height it needs to elevate the water it could actually be less. but in your case the website(?) that your getting the pump from should give you some info on the head loss. could you post a link perhaps?

[Reticentregret]

i wanted this pump Coralife Turbo Sea Circulation Pump-1270 at Big Al's Online but now im lookin at this one too... http://www.reefgeek.com/equipment/Pu...otor)_by_Iwaki and this overflow eBay: Aquarium Overflow Box 1200G w/ lift powerhead for Reef (item 160114123063 end time May-12-07 20:18:04 PDT)

[ry77]

ok, I need to know how far it will be from the bottom of the overflow to the pump then I can do a little math and figure out which pump would work out better.

[ry77]

you could just get the stronger one and regulate it with a ball valve too..

[NATIVEVAMAN]

You could go here Reef Central Online Community
and calculate your own head flow. Look on the bottom left of the home page.

[NATIVEVAMAN]

I would recomend that you take your tank to your local lfs and get it drilled and have an overflow installed ,around here they charge 75 $'s for the service. That might be 1/2 the price of that overflow.
And remember that manufacurers routinly overstate the ability of there products.Will that siphon actually move 1200 gallons?Protien skimmers are notorious for this. For instance, you have a 100 gallon tank so you buy a skimmer for a 100 gallon tank and wonder why its not working so well. Get one for 150 gallons and it might work great.
As far as flow goes 10x is the accepted minimum,most who are going to have a lot of coral opt for 20 to 30 x flow.In order to get this kind of flow you either need to have a lot of ugly pumps in your tank or have a look at this.Short Take. This drawing shows the system running from the sump.I am going to have a third hole drilled about 6 inch's down from the top water level.All things considered I will acheive 29 x flow.Running from the sump may be very noisy and require larger holes to be drilled in the overflow.
Remember........TRUST BUT VERIFY.

[Reticentregret]

i also found an overflow that handles 1400 gph but its cost less than the 1200 one different site and i kinda like it more. would that cause trouble or no?

[ry77]

well neither of those pumps will deliver the full capacity that they say because of head loss, so if you use that evrflow you would have to find a way to slow the flow again with a ball valve.

[NATIVEVAMAN]

I would suggest taking your tank to your local lfs and have it drilled (assuming its not full of fish) It only costs 75$'s and it would include an overflow box and piping. Thats less than the siphon hob overflow. Also 10x flow may be a bit slow for most corals. Most people are opting for 20 http://www.advancedaquarist.com/issu...003/short.html 30x flow.Have a look at this article qand see what you think

[NATIVEVAMAN]

Darn link came out in the middle of the text.....geeeeeeez im sorry

[Reticentregret]

so you need to match perfectly huh dang how do you know when you get it right that sucks.

[ry77]

yea, pretty much. I would think it's right when the water level in your tank and the sump are staying the same.

[Mattfish]

Good question here and it made me think of my planned setup. I've got a 125g tank w/ 2 overflows and was planning on an 1800gph MagDrive pump. It's 4 feet from bottom of sump to top of return, although since one return will be a longer flow to reach (the other end of the 6 foot tank), does this add any complexity? (one return is straight up and one is angled).

I get the point about ball valves to regulate since that'll equalize things, but even though I have two overflows to drive the water to, am I way overdoing it? Any better recommendations on pump size?

[NATIVEVAMAN]

Matt if you have two overflows the good thing to do would be have two return pumps,the the extra distance wont make so much difference.If your drain line is a 1 inch pipe it may not handle 900 gallons an hour. I cant find any data on drain flows.The best guess average from 3 lfs's is 725 gph.But thats not a bad flow rate.12x.Hey this is what the challenge of planning is all about.What did you think of the link that I sent you?

[ry77]

what will be the gph through your overflow?

[Mattfish]

The "I'm stupid" answer is..... I don't know. The model I expected to use is the AGA MegaFlow Mod 4. Nothing I've seen talks about a max capacity or usual throughput. I assume there is a maximum rate that this will accept and I'm surprised they don't publish something about that. I assume that the skimmer will have a max throughput also, but I would guess this is less important, since it's not in-line (is it?) so that if "dirty" water doesn't pass through the first time, it'll get caught and sent through the skimmer on one of it's many passes by.

[Reticentregret]

wel i like the short take its cool... i only wish i could get my tank drilled but the bottom is tempered damn pennplax or well does that mean the sides are as well?

[ry77]

when I have a few minute i'll see what i can figure out about that for you mattfish

reticent, most tanks are only tempered on the bottom

[ry77]

I went on AGA's website and found that any of there tanks over 110 gallons with two overflows put out 1200gph through the overflows. so i'm assuming that this is the flow you will have. the magdrive pump has a max head of about 21 feet(the point at wgich no water would leave the top of the pipe) and at 4 feet of head puts out about 1375gph
(below is a chart of the flow rate in these pumps with a discharge curve) it goes as far as tellin you the pump will cost about $8.35 a month to run)


Mag Drive Pumps

[Mattfish]

Thanks VERY much! The way you figured this out is a good lesson in both researching and tank-keeping math. (I also looked at your myspace page and see why figuring this out was probably easy for you, where it just left me confused - Bronx Science background and all....)

So, bottom line is I either want to:

• Get a smaller pump because this one will over-pump more than the oveflow can handle returning - 1375 vs. 1200, or
• Increase the head distance by about 1 foot (if I read the chart right) which doesn't make sense to do, or
• Put a ball valve in (which I should do anyway) and throttle it back to create an even water level in the sump during operation

So if I've learned something, choice 3 seems to make sense since it's pretty close and the sheet you linked to on the pump recommends ball valves anyway for several reasons.

Did I get this right? And thanks again for all this info!

[ry77]

well if your going to have two returns ( I think you said you wanted too) then you would probably need a bigger pump or two smaller ones.

the ball valve will come in handy if the pump ends up not being enough and the overflow is filling the sump faster than the return can return the water and can come in handy a few other ways.

you will also want to put a check valve on the return line(s) so that if the power goes out you wont create a back siphon through your return line and possibly flood your house.

your welcome,
Ryan

[Mattfish]

Thanks - the pump size issue is important, but not flooding the house is even more so. It looks like I'll be going over to my lfs tomorrow to get everything ordered, so I'll bring this up.

With two overflows, and the size of the tank, I don't see how I can avoid having two returns so we'll probably need to up the size of the pump.....