View Full Version : External Pump: Iwaki or Dolphin

11/21/2014, 06:39 PM
I am in desperate need of some guidance. I need to replace my existing Iwaki MD40RLT because I am just not getting enough flow for all my accessories. I currently have a frag tank, skimmer, main tank, chiller, and GFO that requires a pump. At this moment the skimmer and main tank are on the MD40RLT while the rest are on a Mag 3 pump. The flow really sucks on all equipment.

All equipment are connected with a 3/4" pipe (nothing I can do about that now). The pump sits below the tank next to the sump. The MD40RLT is plumbed to the sump via a 1" pipe reduced to 3/4". My idea is to plumb all the 3/4" into a single manifold to distribute.

My requirements are that I reduce electricity usage, get rid of the Mag 3, and hopefully reduce noise level while maintaining reliability. For these reasons I've narrowed my choice of pump to Iwaki OR Dolphin AMP Master Type 4. Not considering reeflo, blue line, or pan.

I know these pumps are designed for very different applications. But would I be ok with a Dolphin amp master diamond 4750 OR should I get an Iwaki MD70RLT?
I think the 70RLT will work for me, just don't like the fact that it doubles power consumption compared to the MD40RLT. I really like the Dolphin but not sure what kind of head pressure I'm looking at. I see there could be some pressure feeding water into an H&S external skimmer. Not sure how much pressure would be on the Chiller.

Not sure how all those 3/4" adds to the head pressure equation. By the way the longest run for the 3/4" is to the frag tank which is maybe a 6ft run.

I appreciate any help. I'd like to figure this out soon so I can get my black friday deals on the pump.

11/21/2014, 07:03 PM
If you want more flow you are going to have to increase power use. Is the skimmer functioning properly how it is setup now? Why not replace the mag 3 and leave the current return pump intact?

Sounds like you are already invested. I would get another MD40RLT and run the other stuff off of it. I would make sure they both have the same unions and are interchangeable. Install a small return for the frag tank off the current return pump, nothing major just a little flow. If the frag tank pump fails the main one will keep it running until you discover it. If the main return pump fails you can put the frag/chiller/reactor pump in its place until you get a replacement.

The closed loop pump on my frag tank is the same as my return on my display. They can be swapped in less than 15 minutes at 4am by a complete rookie over the phone.

11/22/2014, 06:42 AM
FWIW Blueline and PW are the same pump, and almost identical to the Iwaki (sharing a common designer). More pump means more power, no way around that really; especially if you want reliability. I'd be inclined to keep the Iwaki and replace the Mag, perhaps with something like a Sicce.

Vinny Kreyling
11/22/2014, 07:58 AM
The Iwaki 70 I had was 265 Watts.
Pipe size here is your enemy.

01/13/2015, 12:55 AM
thanks everyone. I went ahead and bought the Dolphin Type 4 4750 pump and the Iwaki MD55RLT. The dolphin 4750 turns out to be equivalent to being somewhere between the MD40RLT and MD55RLT (but with the MD55RLT reduced with a ball valve). The MD55RLT really puts out some good pressure. It almost overflowed my tank because the return couldn't handle the flow rate. The Dolphin runs near silent compared to the Iwaki. You almost have to touch the pump to ensure its still running. Now the only sound from my tank is the skimmer, so I'm in search for an external skimmer powered by a non-chinese DC pump.

01/13/2015, 03:59 AM
I'm in search for an external skimmer powered by a non-chinese DC pump.

That would be a Royal Exclusive

01/13/2015, 07:49 PM
A vote for the Iwaki MD series in general. I have a MD30RLXT that has been running 24x7 for 17 years.

01/14/2015, 12:56 PM
I'd vote for Iwaki MD series also but Iwaki's increase my tank temperature 2 degree's. My iwaki may last 17 years but I don't think my chiller will. With the Dolphin, my chiller never kicks on anymore. The good news tho is I can swap between my Iwaki and Dolphin easily.

I looked at Royal Exclusive. I need an external skimmer utilizing a single Royal Exclusive DC pump. That product does not exists today. I am thinking of fabricating something to put a DC pump on my H&S A250 external. I'm thinking there is a market for a DC pump replacement for a eheim 1260.

01/14/2015, 03:11 PM
I switched my MH/VHO setup to LEDs. I have to run heaters now - no need for cooling at all.

01/14/2015, 03:22 PM
nice. What is your mean temperature of your tank? With iwaki's I was at 80.5 or 81. Without iwaki i am at 78-79. I read somewhere that reef temps can range from 78-84 but I get nervous above 81.

I can say that at 78, my corals are growing again and seemly growing fast. But then again I think it has more to do with switching from Hydra 52 to kessils.


01/14/2015, 03:24 PM
I ran (3) Dolphin's 3600 pumps on my 750 reef for almost four years with no problems....They were very quite but not pressure rated so plumbing design is important.

01/14/2015, 09:04 PM
I'm at 77 degrees. My sump is in my basement which helps. I accidentally switched my heaters off one night and my tank dropped to 73.5 in less than 18 hours.