What GPH rating pump for 120 gallon Tank

jadendo

New member
Hi,

I got a few questions, please help =)
I have a 120 Gallon tank with a middle over flow.

1/ I am using a RIO 3100 rated at 900 Gph pump. Is this sufficient for a 120 gallon tank?
I am thinking of installing another exact same pump in parralle to get it to double the output to 1800 gph of water return back to display tank. I am trying to get more water flow. Is this a good idea?

2/ I am dosing half of a spoon of Kent Kalkwasser to half gallon of top-off water. Is this a good practice?

3/ My tank is 9 month old, and i can not spot any copepods anywhere! I used to see them hanging in the sump around month 3-4, now they are gone.
Is this a bad sign?

Please help! Thanks.
 
Last edited:
Welcome to the hobby! I recommend you read all the stickies in the newb section and then go from there! I have a 110 gallon and im using a mag12

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I have a 120g dt and have had two return pumps on it. My first was a mag 9.5 (950 gph) just acting as a return. I recently changed over to a waterblaster 5000 (1300 gph), and I am now running the return and two reactors off of that pump.
 
If the pump is rated for 900 gph you are probably getting around 625 actual flow.
I would definietely and another one, or upgrade to a larger pump that is rated for 1000 gph or better.

I once had a Rio 2500 melt down in my water change container ruining both the water and container. This was several years ago, but I personally will never buy another Rio pump.
 
I have had great experiences with the Rio pumps, however you probably want more flow. I am using a Gen x mak4 on my 120 feeding the display and refuge. Keep in mind the limits of your overflow as well. I have had good luck topping off with Kalk 1 tsp per gallon, I believe you can go up to two per gallon if needed. Also check out BRS Kalk, I am topping off 2+ gallons per day and the Kent Kalk get expensive...
 
Thanks for all your input. I have just put in an order for another Rio 3100. My live rocks look like they are covered in light ashes, probably because there are not enough water flow to clean them off.

I will look into BRS Kalk. Can you overdose the tank with Kalk?
 
Thanks for all your input. I have just put in an order for another Rio 3100. My live rocks look like they are covered in light ashes, probably because there are not enough water flow to clean them off.

I will look into BRS Kalk. Can you overdose the tank with Kalk?

Yes, you can overdose with kalk. Easily. You need to monitor your alk, calcium, especially pH.
 
Also remember if you have a real high flow through your sump/fuge your water will not have long enough contact time with the filtration to be thoroughly cleaned. You are probably around 600 gph once you factor in head pressure. That is a turnover rate of about 5x an hour, I think that would be right were you want to be. If you are looking for more flow think about upgrading our powerheads in the display.
 
I am running a 1050gph koralia and a 750gph koralia. However it doesn't seem like i have enough of water flow. There are some dead spots that there is hardly any water movements.
I placed mine on one end blowing the other direction.
How do you position your circulation pumps?
 
i run a mag 9.5 and an aqueon 4000 to a 180 dt and i need more flow. for a 120 i would go with a mag 12 or similar and go from there
 
The Mak4 and two Hydor circulation pumps still aren't enough flow for my 120. I have one MP40 on the way and plan on another as soon as I can save up for it... (Ramen noodles for a month should about do it, lol!)
 
I love my mp40. And the added benefit of built-in wavemaking functions and detritus removal (pulsing to keep the stuff in circulation) has been great!
 
I am running a 1050gph koralia and a 750gph koralia. However it doesn't seem like i have enough of water flow. There are some dead spots that there is hardly any water movements.
I placed mine on one end blowing the other direction.
How do you position your circulation pumps?

I50 gallon display, four 1400 gph Koralia Evos, one 1400 gph return pump, positioned as you see in the pic:

IMG_1405s.jpg
 
Usually mount mine split, half on one side the other half on the other. Every tank is different depending on rock work and what type of corals you have it will really change what you need, try adding a 3 Koralia probably another 1050. If it is two much flow, doubt it, you could just remove the 750. I am thinking about going to Vortechs they are expensive but you cant argue with results.
 
I don't mean to revive an old thread, but my LFS had me buy a 1700 gph for my 75. Reading this I'm like ***? So if I upgraded I wouldn't need to upgrade pumps.

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I don't mean to revive an old thread, but my LFS had me buy a 1700 gph for my 75. Reading this I'm like ***? So if I upgraded I wouldn't need to upgrade pumps.

Sent from my SM-N910V using Tapatalk

If you mean return pump, yeah that's pretty huge. I would have gone with about 6-700.
 
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