View Full Version : flow rates?

09/28/2008, 10:59 PM
In the process of building a 150 gallon reef. Total system volume will probably be about 180-190 gallons.

What is an appropriate turnover rate? I'm trying to figure out what size bulkheads to use and how many. Any articles on how to calculate flow rates would also be helpful.


09/29/2008, 12:13 AM
What kinds of criters do you want to keep?

09/29/2008, 02:04 AM
The most you can afford. Good circulation is vital to a reef aqaurium.

My 156g has 2200GPH with 2 pressure rated pumps and a Tunze Wave Box for surging the water.

09/29/2008, 09:21 AM
you can almost not have enough flow,,,,found that out the hard way

09/29/2008, 09:39 AM
I would shoot for 1,500gph through the drain/sump/fuge. Then add either a closed loop system or a couple strong powerheads.

09/29/2008, 09:50 AM
If your going to want SPS - target 40x - which for you would be 6,000gph
If you put in 4 1200 gph powerheads - you want the return pump to put out at least 1200 gph.

Use the attached link to determine your actual flow rate of the return pump - you loose gph due to head loss etc.


09/29/2008, 10:12 AM
A minimum of 12 changes per hour is the recommended turnover rate for a reef aquarium. That's 190 Gal. X 12 = 2280 GPH throughput on your return. Be wary that the flow rates you see on the aquarium pumps are usually at 0 feet of head (height to which return water will be lifted). Measure the height from surface of sump to surface of aquarium, and make sure you find out the actual flow rate for a given pump at that many feet of head.

Best Regards,

09/29/2008, 11:21 AM
Don't get total turnover confused with how much flow you want going through your sump. Since you mentioned bulkhead sizes, I'm guessing you're really wanting to know the latter, and firebirdude is the only one who seems to have answered that question. In short, though, the return from your sump should not be your primary source of circulation in your main tank. Ideally, you will have a separate closed loop or powerheads. Then, the question becomes tricky, since it has as much to do with direction and dispersion as it does with total amount of water flow. For instance, 200gph of flow from a very directional powerhead like a Maxijet is very different than 200gph of dispersed flow from a powerhead like a Hydor Koralia. Generally, you want large amounts of dispersed waterflow coming from different directions. What I'd suggest is figuring out what you'd like to use for flow (closed loop or specific type of powerhead), and then people should be better able to help you figure out the specifics.

09/29/2008, 11:26 AM
so, when you calculate your turn over rate, do you use total system or display? the 2 are very different for my system i am getting started.

09/29/2008, 02:49 PM
Thanks for the input.

At this stage I'm just looking into system turnover. Basically how many times the tank turns over/hour. This way I can figure out what size bulkheads to put into the tank and subsequently what size return pump will be required, of course accounting for head loss.

As for internal flow, I was probably going to go with either a closed loop system or some Koralias ( I <3 them) but I've been reading about these wavemakers and apparantly they address circulation concerns nicely. Input?

Someone asked what type of stock I'm thinking of. At this point I want to stay as open as possible. Basically saying that I want no part of my setup to limit me. Do different coral types require different flow requirements? If so what should I be shooting for what I want to keep?

09/29/2008, 06:27 PM
I'm sure you'll get different inputs as to system turnover. I've heard 4-5x, but I'm sure that's debatable, and I'm not entirely sure whether that includes the water in the sump as well. I think I'm pushing about 200-250gph through my sump on my 46g (20g sump). As far as wavemakers, I don't own one myself, but they're a great idea. If you go with the Koralias, just make sure you get the correct powerheads for their wavemaker. The standard Koralias won't work.

Different corals definitely prefer different flow rates, but that's not to say that one tank can't support many corals with different requirements. All tanks will have areas of higher and lesser flow. You just have to be strategic in your placement. If a coral is getting too much flow, you either move it, reposition your powerhead(s) or put up some type of barrier.

09/29/2008, 07:20 PM
For the flow between the display & sump, ~ 3 - 5x the display size. The display turnover depends on what you are keeping. An all SPS tank will be considerably higher than a soft coral/LPS tank.