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reducing flow on mj mod

phishphood

phishphood

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Soooo, I'm running a modded mj400 in my tank and no matter the positioning, I'm finding that I can't get it to not push sand out of one front corner or another. Right now it's in the back right of my tank near the bottom. It's pointed to the left and angled up and towards the back wall.

At this point I'm looking into ways to limit the flow on it. I'm already deciding that I'll put it on a timer to run ~14 hours a day or so (I know of the noise issue w/ the on/off ). Other than that, I was contemplating creating something to either cover the shroud intake, or the output of the mj. Any thoughts on which would be more effective? By far, covering the intake part would be the easiest, but it wouldn't be that much harder for me to cover the output either.
 
You can always cut the impeller smaller. That will reduce the flow. I won't not put it on a timer, what would be the point of that?
 
I suppose I could trim it. But should I be worried about making it off balance?

The timer is just so that there is higher flow in my tank for only half the day. The other 10 hours, my 2 MJ600's will be on a chauvet timer providing alternating, lower flow.
 
Cut carefully and slowly. It will work.

Are you doing lower flow when the lights are off? This has already been proven to be a bunk theory.
 
Basically when lights are off. I'm not doing as to try to replicate nature or anything. I'm just doing it so that

a) at some point in time my tank will have alternating gyres vs simply always having the current run in 1 direction
b) I tend to target feed after lights out/before lights on. The high flow makes it darn near impossible for me to target feed w/out covering the coral w/ a cup or something of the like.
 
[quote author=phishphood link=topic=5140.msg63260#msg63260 date=1226332865]
It's already about 3" off the bottom and pointed upward (but not so much that I'm shooting water out the top.
[/quote]
Really.... what size tank is this on again?
 
[quote author=phishphood link=topic=5140.msg63291#msg63291 date=1226339189]
24x20x18tall. Pump is on the rt side wall, at the bottom back of it. Front left corner of the sandbed is...not sand anymore.[/quote]
Oh ok. I can see your problem.
 
I second what Phong said, I have a Koralia 1 that I'll gladly trade for a MJ400. But, if you want to keep it, there are three things I would suggest:
1. Cut the output "jet" this will make the current less precise and it will disperse more rapidly.
2. Cut the output jet and put on a DIY eductor made of a 3/4" or 1" PVC endcap. Again, this will make the pump stream less precise and therefore less efficient thereby having it disperse sooner.
3. Make a DIY flow distributor out of some 1/2" PVC with holes drilled in the side.
 
You guys know I'm talking about a modded MJ400, right?

Phong, if you're interested in just the plain old MJ400, I'll gladly make the trade. Heck, I'd even prefer to do it with my 600.
I'll look into making eductors for my MJ's if I can't figure out a way to lessen the flow of the 400. I previously had 2x900 running alternating but there just wasn't enough water movement. Maybe if I bump it up to 1200's alternating w/ eductors I could make it work.
 
OK, missed the part about the mod....I have a 600 mod on my 120G and I can see where you are running into problems.

OK, so you nee flow but right now it's traveling across the tank and down the corner to the sand. Been there, done that. Here's a suggetion (cheap and easy):
Take a piece of airline hosing and lay it over the mod output then zip-tie around the end of the mod to secure the airline to it. Make sense? My hope is the air line will break up the flow. The best thing would be to have some kind of wedge where you could split the flow exactly as you want it, but this option should break up the flow while still leaving enough for good turbulence. Now, airline may not be enough so perhaps you could fashion something better out of PVC. Just shooting from the hip here.
 
Man, just cut down the impeller. It will cut the flow and it does work. I've cut down impellers in the past.
 
So covering the output of it then. Makes sense. Time to play acrylic again!

iani- I want to leave that as a last option for me. I plan on upgrading once I finally get out of apartments and would love to still have the right size prop. I'm also scared I'll screw it up.
 
Well worse case scenario you are out 15 bucks when you want to increase the flow again. If you got the sureflow kit you should have two impellers, the bigger one won't work on the mj400. Why not just cut that one down a lot smaller.
 
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