Cavitation

[Saboral]

As you all know I am running an Iwaki 70 as my skimmer feed and tank return pump. The pump intake is a 1" up and over out of my sump. The output side of the pump is 1" so I took a 1" line to a Tee and split off a 3/4" line for my return. The 1" continues on to the pump. Both outputs after the T have a ball valve to regulate the flow.

I have been dealing with "microbubbles" for sometime now and tonight I went and checked the up and over for possible obstructions and found a piece of broken acrylic that had gotten sucked right up to the intake and was just about blocking half of the pump intake. I removed it and reset my pump and everything was good again for a moment. Then I noticed bubbles and it dawned on me, cavitation. I closed down the flow on each valve a bit and got the hissing sound and vibration in the pump to stop. After a bit of calibration with the valves I have a pretty good flow in going both ways.

Now the problem is thus, I have what I believe to be "acceptable" flow to the tank (i.e. when I put my hand to the return I can feel a decent flow). I think that I am under powering the skimmer though because the water column in the skimmer just isn't what I think it should be. So now I have three possible solutions and I am trying to narrow the choices down. I want to rank these in order of functionality, ease of installation, and future costs (i.e. electricity, maintenance, etc....).

1) Run a 1.5" or 2" up and over to the 1" pump intake to ensure adequate volume to the pump.

2) Remove the return from the Iwaki and run it from a seperate Mag 4 I have in the sump.

3) Remove the second beckett injector and just run it with one injector (finer bubbles if all the pressure is to one.)

 

[Doc's69]

If you keep both becketts you almost have to have just the 70 running it, i looked through a ton of stuff here on RC and some folks were trying to use a mag 12 on the skimmer but it needed the pressure rated from the 70 or something comparable, now that being said... that is a lot of skimmer for your tank you most likely could get by on one beckett, just a thought

 

[Saboral]

I feel like if I do one beckett it would probably be a lot better since I really don't want to completely strip the water column. I think I will just go get a union and turn it into an end cap for one of the lines, remove the second injector, and cap it at the skimmer box.

 

[ade]

Like Steve said you are going to need all that pump to run that skimmer. I don't think that you can over skim, I think that you can have too large of a skimmer for your tank. You are only going to pull out what you put in, so I would think that your skimmer is going to run idol.
You didn't have a load (fish) on your tank when I was there. So I would takeout one of the becketts and see if you can down size the pump and run one beckett.

 

[Saboral]

Yeah thats what I did and now I am getting a slower but drier dirtier foam and no micro bubbles, it looks damn good. When I move to my new place I am going to build a 90 gallon sump as I will be adding other tanks to the mix.