RSM Pump mods for more flow !

[Herbie]

Hey,

I just recently acquired a Red Sea Max 130, and of course I couldnt leave well enough alone! Time for some mods !!! I not doing a skimmer on this tank.......just a big refugium next to the media basket. I am going to fab up a removable slide in fuge for that. Already have 2 underwater fuge lights ready to go.

Also changed out the lighting to LED's. I didnt want a DIY a LED /Heatsink build, so I just retrofit 6 Ecoxotic Panorama pro modules in the stock hood...........yes 6. I will post up some pics of that shortly if anyone wants to see it. It all fits inside the hood in the stock location. Can even use the cover shield if needed. The light output and color is way more than I was hoping for ! Actually it may be too much, lol. At least I can dim it down when needed.

 

Now, onto the stock pumps. Just ordered 2 new pumps, and had to see if they could be "helped" a little. Yes, I did play around with MJ 900/1200's and I just didnt like the fitment, and the noise issues that went with them although the extra flow was great. I really like how the stock RSM pumps are held in place with the screw on nozzles. They are pretty quiet as well.

After inspecting the stock pumps, I saw there were improvements to be made! Basically there is a lot of restriction in the intake/volute and also in the pump output on a stock RSM pump. So.........out came some basic tools for this mod.............this is about all you will need. BTW, the "bit" is a short carbide, tapered ream with a 1/2" width at its widest point. So, a short 1/2" ream, small round file, and a straight edge razor blade. I would NOT attempt to do this mod with a "drill bit". It may grab, and break the thin walls of the pump intake/output we are trying to enlarge.

 

First we will start with the pump intake. Here is a picture of the difference between a stock pump, and a modded "reamed out" pump intake tube. Stock is on the right. As you can see, there is a lot of restriction in the stock intake volute. (the nozzles are just used to prop up the intake volutes, so you can see all the way through them for the pic, so dont get confused!)

 

The volute does seperate from the tube...........I never knew that! I may try to find a longer piece of sch 80 to replace the small tube, but thats later.

 

Ream out the intake volute to 1/2" and clean up all the plastic bits with a razor blade and file to make it smooth.

 

 

Next on to the pump, and output. Pull out the black plasic thread on adapter from the pump. Its only lightly epoxied in place and should come out easily with a slight twisting and pulling motion. Use a pliers if needed. Here is a pic of the stock pump output after the adapter was removed.

 

Now, remove the impeller, and ream that "square" hole in the stock pump to a nice smooth round (and larger) hole. This is only reamed until the "square" is gone and the hole matches the pump .

Here is how far the ream fits before drilling it out.

 

Here is the reaming to the proper depth.........

 

Clean up the plastic bits with a razor blade and file when done. Use the file to shape the pump output to flow better after your done reaming.

Here is a view of the pump output when all done.

 

And finally, a side by side view of the stock RSM pump next to the modded pump. Stock pump is on the right.

 

Finally, I reamed out and chamfered the pump output "nozzle" so the flow from the pump into the nozzle was nice and smooth.

 

Now just epoxy the nozzle adapter back in the pump output. I used a 2 part epoxy in the double syringe applicator. I used 5 minute epoxy, but you could use a slower cure if you want.

 

I tested out the new modded pump compared to the stock unmodded pump and was quite happy with the amount of flow coming out of the modded pump vs. the stock pump. I would say that the modded pump was putting out approx 50+ more GPH than the stock pump. The modded pump flows similiar to a MJ 900 now...........not quite a MJ1200, but a lot more that the stock RSM pump.

I like the higher flow rate. I really like how the pump fits exactly like it should in the stock location using the screw on nozzles. One other side benefit is that the modded pump seems to be quieter as well. Maybe because the modded pump is not restricted like the stock pump ? Is does sound quieter though.

I may try to fit a larger impeller in the pump if i can find something. There is a lot of room to fit a larger impeller. My fear with this is that the motor block may not be able to spin a larger impeller without shortening the useful pump life. Hmm..........I may try to find something for even more flow. I will update if I find something. Any ideas?

 

Well thats it...........let me know what you think. Its not bad for a free mod to increase flow in the stock RSM pump (well except for some epoxy). These little RSM pumps are only about $15. each vs a MJ900/1200 (Cobalt) that go for $35. or so.

 

It works, give it a try.

 

Oh BTW, attempt this at your own risk. If you are too aggressive drilling the thin pump parts, you could destroy the pump. So just be careful. Keep calm and Carry on !

 

Have fun !

 

Herbie

[Spirofucci]

Wow! Great documentation on a diy that I have not seen before. I may try this (at my own risk) I have two extra RSM pumps anyway.

 

Thanks Herbie!!!

 

Oh btw, are you a dentist?

[Herbie]

Wow! Great documentation on a diy that I have not seen before. I may try this (at my own risk) I have two extra RSM pumps anyway.

 

Thanks Herbie!!!

 

Oh btw, are you a dentist?

 

Thanks, I have not seen this one yet either. I just felt the stock RSM 130 pump's could use some "help".

It works pretty good. I would estimate that this will let the RSM pump around 200+ GPH. The modded pump definitely has more flow when compared to the stock pump side by side.

 

LOL, no I am not a dentist. Just Herbie, as in the Herbie overflow guy, lol.

 

Thanks,

Herbie

[metrokat]

Excellent mod on the pumps, thanks.

[SerenityReef]

Think I will put this to use on mine...

[nsousa]

Nice Mod!

Last weekend I bought some pvc pipe and extended the tubes on my RSM pumps which helped a bit with the microbubbles. Definitely something I want to try. Also could you post pics of your LED mod?

 

Thanks!!

[Herbie]

Update............

 

Well I wanted to extend the intake tubing a little bit to help cut down on micro-bubbles and premature starving the pump of water if the level gets a little low.

I was going to find some PVC or CPVC pipe that would slide right onto the intake volute in place of the small pipe that comes with the pump stock. I couldnt find any of the pvc that would work properly, but I happened upon a PERFECT replacement tube.

 

I found this in my local Lowes ..................

Its 1/2" Poly thin walled tubing used for lawn sprinkler systems and/or irrigation systems. Perfect size - .600 ID x .700 OD. Its almost an exact copy of what the RSM pump comes with, but in a 24" piece.

Here is a pic with the label of the new tubing with the stock tube for comparison.............

 

 

Here is a pic of the new tubing and the stock tubing showing the diameters. Almost identical ! The new tubing is slightly more pliable.

 

 

 

So all I did was cut the 24" piece of tubing in half, and stuck 1 12" piece of tubing on each pump volute in place of the stubby piece that comes stock. It will let the pump "suck" water from about 3" or so towards the bottom of the pump chamber.

Here is a finished pic...........

 

 

This tubing is a perfect replacement in size. It has just enough of a "friction" fit onto the volute, that you will not need any epoxy to hold it on. It holds as tight as the stock tube.

I like that it is black also. Since the RSM back wall is somewhat see through, a white piece of PVC would have been very obvious. Because its black, you cant even see it. Also, the tubing is very light. Much lighter than an equivalent size piece of PVC.

 

You still need to hold the volute/tube assy on to the pump with a ziptie or two ............or................

 

This is optional, but I actually epoxied the volute to the pump. This way it wouldnt fall off the pump, and it would be "sealed" so it would draw any air incase the water level dropped below the pump. I kind of figure at $15. bucks or so for a replacement pump, they are kind of disposable in a few years. It doesnt make much sense to replace an impeller, when the pump is so inexpensive to begin with. I do have spares on hand for emergencies.

 

Oh yea.............cost of the piece of tubing.............. $1.12 plus tax !!! Cant beat that !!!

 

Well, I think I am done with my pumps for now.

 

Good luck..........

Herbie

[StevieT]

1/2" is used for drip irrigation supply. Oh the story of my summer.