Tank return flow rate

stolaas

stolaas

Member
I was at John Newby's Saturday and we were talking about tank return flow rates. I told him I had mine going as fast as the overflow would allow without flooding the tank. He told me that I should have it open just enough to have some flow out of the return but nothing fast. He said this allows the sump to draw more nutrients out of the water.

I just wanted to know what GPH others have on their return to the tank. I had mine at around 500GPH mainly so I could use the return as more current flow. I have a 55g tank just for reference.

I have seen many people use the Mag 5 and 7 for thier return but if that fast of flow is not wanted or needed then why have those big pumps on? I have a Rio 2100+ that puts out ~500 GPH at 4' head.

John showed me his return on his 135g and it was hardly any flow at all. Just curious what others had to say.
 
Stolaas, on my 55 gal I drilled it for a calfo style overflow box, coming out i used 1 inch pipe to go to the sump. In the sump i have a mag 2.5 which then feeds the water back to 55 gal through a 3/4 inch pipe and flow seems to be perfect. Maybe i'll see you at Johns sometime and we can compare setups?? I drive a gold vovlo wagon.
 
Baddraw, that would be cool to compare setups. I drive a green Jeep and I'll keep my eye open for your volvo. I havn't seen a 2.5 mag, that sounds like it would be perfect. The 5 and 7 are just so big. I am putting to use my Rio2100+ at least. I use it for the return but also supplies my protien skimmer so I get double the use out of it.
 
John has two SEIO's in his 135 which add a lot of flow to the tank. The return flow is very small in that tank because of the very small sump he's got. On the other hand his larger tank has a lot more flow. If John was talking about a nutrient export, he must be refering to his plant refugium rather than a sump. As long as you have a good turn over rate, the nutrient export will happen with a high or a low flow. The one disadvantage of high flow through the sump is the possibility of generating micro bubbles. A lot of people use closed loop to add flow instead of relying on a sump return.

Tomoko
 
If 20 times turn over is a minimum amount of flow (according to Anthony Calfo and a number of other experts), a 55 gallon tank needs a total of 1100 gph for the flow instead of 500 gph.

For my 120G I have a Mag 12, two SEIO 1100 just for the flow (at least 20 to 25 times turn over.) I have Sedra 350 pump for my ASM skimmer, Mag 2 for my calcium reactor and another smaller powerhead to send water up to my refugium. Boy, that sounds like a lot of pumps, doesn't it?!

Tomoko
 
Well I have 660 g/hr with my three powerheads, and I can crank up my sump return to 500 g/hr. My concern is, is this wise to have the sump return up that high or keep it low like John said? If I keep it low then I would need to get another power head or two. I had been using the Sump return for more flow but like John said that it needs to be slow to pull out more stuff.

Yea Tomoko, thats a lot of pumps, but you also have a lot of stuff too. I have 5 running though so I'm not far behind.
 
I don't know what exactly John Newby was talking about, but 20 turns is pretty much a current recommendation given by many experts. I don't know where he is getting this idea about a slow sump return for pulling stuff out. The sump for his 135 gallon tank is a Tidepool bio-wheel filter. I don't even call that a sump. He also has a plant refugium under the tank. If he was talking about a nutrient export, he is talking about the refugium because he does not use any phosphate remover or activated carbon (the media for nutrient export) for the tank. The current thinking about the flow through a plant refugium is generally leaning toward a relatively high flow (according to experts like Tom Barr, Anthony Calfo, etc.)

A sump is just a container to hide equipment and it adds some extra water volume (the more water, the more stable the water quality.) Some people add a phosphate remover in a filter bag in a sump or connect a phosphate reactor (such as a phosban/rowaphos reactor.) Some of us also use activate carbon in a bag in our sump, too. Skimmer exports organic substances in the water before they break down into phosphate and nitrate. We need a pretty fast flow through the skimmer via a powerful powerhead to create fine bubbles. Because we need to take the water drained into the sump back up to the display tank, we need a return pump. You don't have to have a powerful return pump if you have many powerheads or an external pump connected to a closed loop to produce a good water flow in your display tank. A lot of people uses a powerful return pump so that they don't have to have a lot of powerheads in their display tanks. Powerheads add heat to water and they are an eye sore. A close loop is very nice because it usually utilizes a powerful external pump which does not add heat to water and it creates a powerful current in the tank.

John is a very nice man and he runs a super LFS, but I still recommend that you do research on your own using resources available through RC, reefs.org, wetwebmedia and the likes, rather than relying on what LFS's say.

Tomoko
 
And if you think about it even 20 times the turnover comes NOWHERE near what reefs expierience in the ocean.

A lot of people are forced to run a slower rate through the sump in order to get any benefit as far as nutrient export because the sump and refugium are one in the same -- in their setup. I am not the one to say they are wrong

I have read and seen first hand that a separate refuge with that slow flow for nutrient export is a good way to go - coupled with a sump, separate of course with a pretty aggresive flow or return that helps keep detritus suspended for eventual removal by the skimmer in that same sump. I am not the one to say I am right.

Tomoko Schum is right on in saying "you do research on your own using resources available through RC, reefs.org, wetwebmedia and the likes, rather than relying on what LFS's say"
 
Anthony Calfo and Steven Pro keep a pretty high flow through their refugiums to keep chaetomorpha turning around. Tom Barr, a marine biologist specialized in aquatic plants and algae, stated somewhere that plants and algae can take up nutrients efficiently regardless of the flow rate. I believe that the idea of a slow volume through a fuge comes more from growing microorganisms to feed the main tank.

Some corals come from high energy areas and some come from lagoons with a relatively slow flow rate. We need to adjust the current/flow rate in our tank to what we keep in our tank. We tend to measure our flow by gph here, but I understand some people outside of USA is starting to measure by feet per minute or m/min.

Tomoko
 
I dont think he is really asking about tank turnover guys.. He is talking about just his sump turnover.. With that said a mag 5 is not to big for a 55.. Infact it only moves about 400gph with 5 foot of head.. Thats about perfect for that size tank Maybe even a lil small..I use to use a mag seven on my 29.. You only need enough water going through your sump to supply your skimmer.. I agree that its not a smart idea to Max out your overflows.. If they are maxed out and you have something clog one a lil then you just flooded your house!

I use Mag 9s on my 180, 60, and my 125.
My Seahorse tank is 35Gallon and it has a quiet one3000 I think..

My return pumps aren't huge but I have closed loops On all my tanks so thats where my turnover comes from..Its alot safer this way because your not maxing out your drain...HTH
 
I brought up the total turn over rate as an indicator for the water flow partly because Anthony Calfo address the water flow in terms of the turn over rate in the article, partly because Curtis started talking about diverting a Rio pump to a skimmer, reducing the return flow back up to the display tank further. I am afraid that 660 gph plus 500 minus the flow to a skimmer is not going to be enough flow in a 55 gallon tank.

8Ball - what is your total flow in gph in your 180? I bet it's pretty high knowing your pump on the close loop system. Do you remember what it is in John Newby's biggest tank that you put together for him?

Tomoko
 
Thanks 8ball, that was what I was looking for - sump flow through, guess I was stating it wrong. I'll keep my return high then. I only hav about 50-75 g/hr through skimmer because its a counter current air stone one so I don't need a lot of flow for that, I'll just use my extra horse power in the return for extra flow then.

BTW, I am thinking of doing a Maxijet mod too, has anyone here done it?
 
I thought the counter current air lift skimmers did not need any other source of water flow through skimmers beside the flow generated by the air lift. The fine bubbles from the air stone create a gentle flow inside the skimmer as the bubbles lift the inpurities into the collection cup. I thought those things use air pumps rather than a powerhead or a diverted flow from the return. Is your skimmer a vortex type skimmer with an added air stone?

Middle Tennessee Reef Club tried the Maxi-jet mod and their project failed unfortunately. Somehow the parts they used did not last long at all. Danh Nguyen's design supposedly works very well. He had a number of threads going on RC that describe the entire mod process with pictures, materials and sources.

Tomoko
 
Tomoko - My Counter Curent skimmer is one I made. I is 3.8" feet tall with the reaction chamber 3 feet tall. The water diverted from the sump return is what feeds it at the top. I have a Luft pump pumping air to 4 limewood air stones to pull the crap out up to the collection cup and the clean water flows through to the bottom and back into the sump. That feed from sump return is just what feeds the water to the skimmer at a slow rate via Ball valve.
 
I saw that mod for Maxijet on the reef chilli site and got forwarded back to Reef Central. I think I will try it and tell you all how it goes. But I am going to try to do it with an Aquaclear 50 instead. I happen to have one here not doing anything because they put micro bubbles in my tank. By the way I switched my 2 Aquaclear 50 's and got 2 Maxijet 900 's instead, NO MORE BUBBLES!!!! :) For anyone searching this site because of the Aquaclear bubble mess just take it from me and go ahead and switch - what a difference!
 
Yea it is tall. I have it painted black so it doesn't stick out like a sore thumb. :) It is just sitting behind the tank.
 
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