Mort wrote:

I just might take you up on that Marc. How old is your Mag 5?

Hmm. Good question. Definitely less than a year, and for a LONG time it was
just waiting to be installed on a system. I can't say it is brand new, but
swapping it for your new Mag 3 might be an equivalent.

After all, Mag pumps are warrantied for 3 years.

Also, what is the rule of thumb for how many times you should turn over your
tank in an hour? (basically, how do you size a pump)

3 to 5 times turnover.

My reef is a 75g. Would the Mag 3 be sufficient enough of a system pump?
at 4' of head it does a little over 250 gph. So that would be about 3.5
times an hour. I think its supposed to be four or so right?

I would say "no way" to a Mag 3 for a return pump. I have a Mag 5 on my 29g's
return, and it does nicely returning 300gph at 5' head pressure.

I've got a Mag 9.5 on my 55g, pushing about 700gph into the tank, which btw is
yet another source of flow (or current) in the display. You'll want at least a
Mag 5, a Mag 7, or a Mag 9.5 for your return. You can copy my plumbing to
prevent pushing too much water into your tank at once:
http://www.melevsreef.com/return.jpg

The vertical ballvalve is slightly opened to redirect some of the flow back into
the sump as my current overflow box can't keep up. I'm going to build a new one
that can one day, if I ever have the time to tinker again.

The reason I ask is, I am currently using a RIO 2100 that came with my
system. Now, the RIO 2100 is one of the pumps the EV-120 can use.

I want you to retire that Rio 2100 now. Just quit using it. Please trust me on
that, and don't take the chance with your reef tank. The last thing I want to
read is a post from you telling us how your entire tank was wiped out by the Rio
having a melt-down. It just isn't worth the risk. The 2100 and the 2500 are
the ones that notorious for this event. They don't just stop running, they
melt, and leak the innards into your water. Electrocution and pollution and all
your hard work, your time and your money is wiped out.

Use the Rio 2100 to mix new sal****er in a trashcan. Use it to pump water into
your tank during a water change. But don't trust it as an integral part of your
setup.

SOooooo, I was thinking to put my RIO on the skimmer and use the Mag 3 as my
system pump. What do you think? Too small?

~Mort

You may hear comments from others stating that I'm being too dramatic, but let's
just say that I'd put caution ahead of risk any day.

Marc
PS: I have a 2100 and a 2500 and use them myself as I suggested above.

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