Rjohn Posted February 23, 2015 Share Posted February 23, 2015 We haven't discussed this lately I don't think so I'd like some opinions on how much circulation I need for a mixed reef tank. I have 7 fish, some softies, and several medium size anemones, red and green. I am looking at getting a new return pump and as usual I read too much. My tank is 75 gallon rectangle plumbed by Shane at Fishy Business and has a 20 gallon sump. Most of yall are familiar with his design. I bought the tank used and it came with mag 9.5 that used two returns. The flow in the tank was poor so I added a couple of water pumps to increase the movement but these require cleaning every week or so. That's a lot of maintenance as far as I am concerned. I took out the two returns and am currently using just one. This improved my flow enough to remove one pump. My flow from the return got weak so I swapped out the 9.5 with another that I had. Things are back to normal but I think I need to replace the old pump. Since I am buying a new one, I started looking into how often the water should be completely circulated. I read in a couple of places that the water should be completely circulated 20 to 30 times an hour. By the specs, a 9.5 raising water to 5 ft yields about 685 gph. By my calculation that results in 7 water changes an hour if I figure the tank and sump at 100 gallons to make the math easier. Is that sufficient or should I go with a Mag 18 which would yield 1100 GPH or about 11 changes an hour? Man, this got a LOT longer than I intended. Ideas? Quote Link to comment Share on other sites More sharing options...
Viet'spride70 Posted February 23, 2015 Share Posted February 23, 2015 I think ur next upgrade for mag 12 would be perfect. Regards ur plumping with elbows, stand height. ..ect. those r restriction factors unless u doing close loop setup. And If u want no ph to b seen in dp, mag 18 is good choice... just my 2 cent... Quote Link to comment Share on other sites More sharing options...
jestep Posted February 23, 2015 Share Posted February 23, 2015 Do you have any in-tank pumps or are you relying on return pumps for all flow? I run about 5x through my sump and about 40x using an in-tank pump for circulation. I've found it less hassle and much quieter to run the tank this way instead of trying to get some blistering flow rate through the sump and return lines. Quote Link to comment Share on other sites More sharing options...
Timfish Posted February 23, 2015 Share Posted February 23, 2015 There's no magic number but I've run mixed reef systems with as little as 4x turnover through a sump. Quote Link to comment Share on other sites More sharing options...
Reburn Posted February 24, 2015 Share Posted February 24, 2015 I have always understood 3-6 turnover through the sump. 10-30 turnover in the tank. Quote Link to comment Share on other sites More sharing options...
Rjohn Posted February 24, 2015 Author Share Posted February 24, 2015 I do have a small maxijet in the tank to aid in circulation. I think I will upgrade to the max 12. I am a little afraid of the 18. I don't want my return to be a fire hose. If I went to the 18, I'd put the T back in the return line and use 2 outlets the way it was originally. Thanks for the advice everyone. I appreciate it. See yall at the meeting. Quote Link to comment Share on other sites More sharing options...
Sascha D. Posted February 24, 2015 Share Posted February 24, 2015 There are two different flow parameters that you are referring to. Water turnover is the amount of water that goes through the sump. Normally the turnover for the sump is 5-8 times per hour. A low turnover allows you to have a refugium and maximize contact time with skimmers and equipment. If you pumped 20-30 times the total water volume through the sump, then you would negate some of the benefits and you'd have to deal with a million micro bubbles. Water circulation refers to the flow inside the display. Polyps need enough flow to prevent detrius from settling on them. Softies, like Xenia, button polyps or yellow polyps, need enough flow to carry nutrients to them and give them motion. Hard corals need higher flow for tissue health and some say Acropora need as much as 35x. Getting up to a flow rate this high is near impossible in tanks above 75g using the return pump alone and circulation pumps are used to push the water around inside the display. Personally, I run about 1000gph through the sump which is about 5x the total water volume. I find it to be quite a bit for my Berlin style sump and if I didn't have a lighted refugium then I would have a micro bubble issue. I have two WP40's and the return going to the display, which gives me around 8,000gph at maximum for a 44x turn over. Everyone that has WP40's knows that it only pumps maximum for about a week after cleaning! I estimate that most of the time the flow is around 6,000 for a 33x turn over. IMO this amount is adequate, but the fish and corals react better when the flow is closer to 44x than when it is 33x. In the future I will likely add another pump to the display. Quote Link to comment Share on other sites More sharing options...
Neon Reefer Posted February 24, 2015 Share Posted February 24, 2015 In my 75 G I run a Sicce 3.5 and at 4 ft head pressure I get ~ 500gph which is ~ 6.5 time the DT volume. I run two Koralia 850s at same time for a DT total of 2200gph in DT or ~ 30 x display. Quote Link to comment Share on other sites More sharing options...
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