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Flow Question?

1638 Views 4 Replies 3 Participants Last post by  ylmaya
I have the return to my system running with a mag 9. I added a maxi-jet 1200 for extra flow. But it seemed like there was TOO MUCH flow. It was kind of hard for the fish to swim in some areas and I noticed that the large rock directly in front of the maxi was covered in hair algae. I turned off the maxi last night to see if the tangs would venture over there to pic. There still seems to be alot of flow because torch and frogspawn tentacles still have movement. (They had way more with the maxi tho).

The problem is I think the mag 9 might be pumping too much through my bio-rocker filter so I think I am going to have to tone it down slightly. My question is I need the maxi 1200 to create extra current? Does the extra current cause more hair algae? I thought that algae grew more in 'stagnant' water....

How do I know when I have the right flow going through the system?????
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ylmaya, i think the general rule of thumb is you want to cycle the total amount of water in your tank 10 times per hour. i'm not sure what size tank you have or what type of corals. but if you could include that then some of the experts could really help, also include the shape of tank as well as maybe dimensions. my 0.02
Tank is a 65G (with an extra 15G container plumbed into the sump for additional water volum in the system)

Tank dimensions are 36"w x 18" deep x 24" high.

Currently holding 100lbs of misc live rock. 5" aragonite DSB.
Torch, Frogspawn, Plate, Fire & Leather - Corals
Tangs, Clowns, Gobies, Blennies - Fish

Running a bio-rocker sump/filter on a mag 9 return. In sump is also mag 7 which powers Nautilus skimmer. Also have maxi-jet 1200 for additional circ in tank (but currently shut off). Plumbing is 3/4" pvc. Have ball valves (currently open) on both return and overflow.

Return enters tank about 8" from left side. Return enters at a diagonal pointing to the front right corner - hits glass about 12" from far right. Overflow is on far left. Placement of maxijet WAS about 8" from Right side to make a diagonal cross current.

Please let me know if you need more info. Thanks.
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Well, water movement is pretty relative... it mainly depends on how big of a mass of water you're moving at once.
While our tanks may seem like 'high' flow, I don't think there's any way we could come close to the water movement in the ocean without knocking our tanks off their stand. :)
In my tank for instance (a 55g) I have a Mag5 return pushing about a 6' head, so it's running at about the 300gph level through the sump.
I also have 6 MJ1200's that alternate on and off (3 and 3) with a wavemaker, and they are 295gph each.
So, if you do the math on that, I average somewhere around 1100gph circulation... but it definitely doesn't 'look' like it.
I have some of the powerheads pointed toward the water surface (using the supplied directors), and the rest are pointed across the tank where they contact the glass a couple times before the current washes over the reef... this makes for a large mass of water moving around, rather than the direct flow from the powerhead nozzle, and makes it look more like the ocean surge.
My tree coral sways back and forth a good 3" or so... my Goniopora sits in the middle of the tank, and sometimes gets blown around pretty good as cross-currents collide, but not enough to make it close up.
My sandbed stays put though... I don't have any problem with 'jetwash' blowing it around.
I've never heard of current causing hair algae... it's usually the build-up of phosphates (like fish poo) that causes hair algae blooms.

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I think the hair algae is just my normal cycling process since the tank is so "fresh" (only 6 weeks old). I am going to do my first real water change (10G) tomorrow so I am sure that will help. I am not worried about the algae for now since not all the rocks are covered and all the polyps (I got some encrusting polyps othat came with a couple of my rocks) are still out and ok.

Thanks for the feedback on the flow - it was reassuring. I think I'll leave the maxijet on then.
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