Introduction to Flow, Tank Turnover, and Powerheads for the Reef Tank, Part 1

ca1ore · Mar 20, 2019

MnFish1 said:
PS - another example - If my return pump broke for some reason - I could easily move my heater from there to the tank - and everything would be fine probably for a long while. If I took my dosing tubing and put that into the main display I could go without my sump indefinitely.

True, and lots of folks run tanks without sumps. I do think the surface skimming capability that a sump enables is underappreciated though.

My tank turnover observations about were only about the fallacy of matching sump flow with skimmer throughput. There may certainly be other reasons to want more or less flow. I suppose mechanical filtration may be one of them - though I don't run mechanical so that wouldn't be a factor for me.

MnFish1 · Mar 20, 2019

ca1ore said:
True, and lots of folks run tanks without sumps. I do think the surface skimming capability that a sump enables is underappreciated though.

My tank turnover observations about were only about the fallacy of matching sump flow with skimmer throughput. There may certainly be other reasons to want more or less flow. I suppose mechanical filtration may be one of them - though I don't run mechanical so that wouldn't be a factor for me.

Yes - agreed - Lets say the skimmer processes (i.e. removes EVERYTHING (hypothetical)) at a maximum rate of 300 gph (made up number) whether you put 1000 gah or 10000 gallons per hour into your sump the amount the skimmer will remove the equivalent of 300 gph. If you put 200 gph- everything will be removed (in this hypothetical example). IMHO - the key point is not the amount of flow 'through the sump' - rather the total flow of water through the tank.

In the case of 200 gallons/hour going through the sump where the skimmer was able to completely clean 300 gph, it may be more efficient to increase the flow. IME - there is a lot of recirculation in the sump - such the the skimmer (almost no matter what the flow) is working to maximum effixiency

WVNed · Mar 20, 2019

I use 6 x tank volume for my sump flow. My heaters and skimmer are in my sump. I don't run anything else. At this rate the sump stays the same temp as the tank and the skimmer works as it should so I have adequate turnover. That is all I need it to do for my system.

My total flow is based on the needs of the tank and what I have in it. This can change drastically. I don't need to redesign my sump. Just change the gyre pump programming.

They are really two separate things.

The difference between a ditch and a coral reef
Both get lots of light, both have water.
A ditch grows algae and a reef grows coral.
It's the flow.

I would also like to point out I have 2 gyre pumps. each is rated at 2300gph
But I run them at 50% so 2300 gph for both
and I alternate them so only one runs at a time
so that's 1150gph actual flow.
not 4600 that the pumps are capable of.
plus my sump flow that gives me 22 x tank volume.
My pumps are rated 714 + 2300 + 2300 = 5314gph but I actually only have 1650

I often inquire when someone is having problems about their flow. They always
reply with what pumps they have in their tank. That really tells me nothing.

jaxteller007 · Mar 26, 2019

I guess this thread is as good as any to ask. We have a 75g and I think I need to adjust the flow some. It's mainly a FOWLR but we do have one Duncan that has done really well. Until we removed some rock out of the tank and moved him. He's not dying or anything but doesn't seem to like the new spot. I'm going to probably try and move him back closer to where he was tomorrow but thought this would be a good time to see if I need to adjust the powerhead/s to get the proper flow going. The tank is a reef ready with the corner overflow on the left side. My return is ran up the back still from when we had a non reef ready tank so it's coming out on the right side pointed left as you can see. Right now I have one hydro 850 on the left side, butted up against the overflow about halfway up the glass and angled slight towards the front. My return pump is a Sicca 4.0 turned all the way down if I recall correctly, or pretty close to it. Are these two combined enough flow for the tank? If so should I adjust the power head placement? I do have another hydor 850 sitting unused in a box but that seems like it may be overkill for this tank? I also have a couple small, cheap power heads I use when mixing up water if it would useful to place them somewhere? They are those sunsun "540" gph ones lol.
In addition to making sure the flow right, I'm hoping to try and stir up a little more of the stuff that settles on the bottom without clouding the tank. I had it doing pretty well at one time but it created a huge sinkhole at the front of the tank. I have enough sand piled up near rocks cause of the pistol shrimp/goby pair, don't need more low spots lol. Here's a couple pics that might help, sorry they are not great quality. Still haven't gotten the hang of that aspect.

Neptune 555 · Mar 30, 2019

OK a tad off topic.... In the photo you show an emperor anglefish in a reef. How is that working out? I was thinking of a Regal angelfish in a 180 mixed reef.

thanks! have always wondered what is the right reef flow!

jaxteller007 · Mar 30, 2019

Neptune 555 said:
OK a tad off topic.... In the photo you show an emperor anglefish in a reef. How is that working out? I was thinking of a Regal angelfish in a 180 mixed reef.

thanks! have always wondered what is the right reef flow!

Who me?

BeaverLakeAndy · Feb 16, 2020

Is there a such thing as too much flow? My return pump is rated at 1,900 gph and it's at 100% power. I have to Tunze powerheads running in pulse inverse of each other. They run at 100% and 50%. They are rated at 2,510 gph at 100%. By my calculation the system is running at 49.26 turnover per hour.

It's 125 gallon tank with sump. Total water volume after displacement is 115 gallons. It just finished cycling and right now it's FOWLR, but will be mixed reef soon. Is the flow/turnover too high?

vetteguy53081 · Feb 17, 2020

Neptune 555 said:
OK a tad off topic.... In the photo you show an emperor anglefish in a reef. How is that working out? I was thinking of a Regal angelfish in a 180 mixed reef.

thanks! have always wondered what is the right reef flow!

Emperor angel? I see a desjardini sailfin tang