400 gal DIY Reef - Retirement Project
 

Hello fellow reefers,
I'm in the very early stages of building a fish room that will house a behind the wall 400gal mix reef tank size 96x32x30high. Just a little background on myself; I was in the hobby about 35 yrs ago and went through the usual 25, 40, 90, 135 gal progression. Then I got married and sold everything. I want to get back in the hobby but want to skip the tank progression phase so I decided to jump right to my dream tank. At this time I'm just finishing the basement media room and will soon start the adjacent fish room. So far I purchased someones entire 125 gal reef system which will serve as my sump and spare tank. I also just purchased a synergy reef shadow box overflow and a Reef Octopus 250INT from BRS. That's it so far. Stay tuned for progress reports and lots of questions about tank flow and lighting.
Cheers !
Attachment 397765.

After reading several large tank project threads I'm wondering if two 16" Synergy shadow box overflows are enough ? Should I go coast to coast ?

A lot depends on how much flow you want through your sump. Old school thought was always 110 time tank volume per hour. Current trends are 3-5 times tank volume. The thinking being most skimmers an not process any more than that an hour so no point in wasting money pumping more water than needed up 5-6 feet. Skimmer size and sump size and design are big factors here.
I have around 5 times flow on my 300 as my sump really will not handle more. My skimmer processes about 1/3 of that an hour I am guessing. I don’t want that low flow through my sump as I use macro algae’s to remove nitrate and phosphate. The higher flow is better for algae growth.

laverda, you make some excellent points. I dug through my notes and this is what I had planned;
Sump is 125 gal with a Reef Oct 250 INT. I plan on having a refugium. My goal was to aim at 5X tank flow through the sump however with plumbing headlosses it will probably be in the 3.5-4 range. The overflow is rated at 2500 gph if you utilize all 3 outlets. I plan on using 2 for and leaving 1 for emergency.

I forgot to mention that the sump return chamber hold 2 pumps. My thinking is to size the pumps so each can handle the 5X flow and run them at 50% during normal operation. If one fails I can crank the other to maintain proper flow.
Question: is this a good strategy or waste of $, should I size pumps for 1/2 the required flow and just run the tank at reduced flow until the failed pump is replaced or repaired ?

More flow questions;
Consensus now states that you need 50-100X in tank flow. What does this really mean?
If a gyre pump is rated at 5000gph does it move 5000 or 10,000 gph ? What it pushes out must equal what it sucks in hence water movement is really 10,000 gal ?

Either way will work. I planned to to have two pumps with a higher flow rate for redundancy, but my sump could not handle that much flow. The return section would run low and it would start sucking air with just one pump on maximum. I could have gone with two smaller pumps, but had already purchased the pumps.
Option 1 advantage. If your using DC pumps you can control with an Apex or other controller, you could have them pulse up and down opposite each other there bay contributing to changing flow in the tank. The disadvantage is higher cost.
Option 2 will work great as well. 1/2 flow should not be an issue if one pump fails, assuming you will have additional flow in the tank.
In either case you could put one pump on a battery back up in case of power outage. There is no need for both to be. I would also have one flow pump near the surface on a battery back up as well.

That is recommended for SPS tanks. Not many people have 100 times flow. Less for other types of tanks. Most consider the pumps rating as the flow rate as that is how much is going through the pump. The flow from your return pumps also counts and can be increased with educators.

Good point on the backup pump configuration.
50X direct flow = 20,000gph yikes = lots of $ :(

A 16” synergy overflow with 1.5” drains can handle 2500GPH, however, they suggest only 1500gph for dead silent operation , bean animal configuration.
I have one and push only 600gph through it with reduced 1” drains.
2 Eheim 1250 , 4ft head.
Or you could go with 2 reef savvy ghost overflows each at 21” long and slimmer than the shadow overflow too.

eutimio, I think I'm going to go with 2 16" overflows one at each end of the tank. I ultimately only need 1500 gph total to achieve desired flow through sump. This should give me plenty of reserve capacity and hopefully run ultra quiet.

Congratulations on your build.

I have a single 16" Synergy overflow on my 215 gal. I am very happy with the overflow. I run a Little Giant - 4-MDQX-SC Inline Pump with about 1100 gph going through the overflow. It is very quiet. That said your decision to run two on a 400 gal is a good one even though you are only needing 1500 gph. Like you said the reserve would be nice, it will be dead silent and you should never have a concern about overflow failure flooding your home.

"Confessions of a Well-Seasoned Hobbyist" is a good youtube video to watch. I found the information shared confirmed my feelings on most things I have learned over the last 22 years. One is LED lighting. I use to run MH. I have been running 165w Full spectrum Ebay black box LED's over my tanks for 5 or 6 years and have found them to be economical and easy to repair should a LED or other components fail.

if you want to do a comparison I suggest looking at exoticmarinesystems.com. High quality overflows and he can customize to whatever specs you require. My tank was a used and was already drilled in the back. After a series of measurements and emailing back and forth I was provided a test template to confirm the hole pattern matched and then they built me a 24" overflow with my existing holes. Really top notch customer service. Eshopps and Synergy would not make any changes which is understandable with the number they mass produce.