critique Biocube 29 Sump design

[West1]

Hi all,

I have a Biocube 29 and I am in the plumbing process. I need a solid design and need the sump before I make my final plumbing. I am new to salt so pls bare with me.

I know corals need high flow rates and I chose a Fluval sp2. I will have 2 one inch herbie returns straight to the sump (no 45's or elbows). Here is a brief picture of the cube and a sump design I came up with2 .25" thick acrylic. 16X16X16 is the vision.

Pls critique the sump design, I am open a complete redesign.

Thanks for the help!

 

[West1]

Is the height of the overflow to high? It's about 1/16 from the bottom of the lid trim. Will be pushing about 800gph

Material is HDPE plastic

 

[saltyfilmfolks]

When most refer to flow there's two basic types. Return rate from the sump and turnover in the tank. In tank can be high and low depending on the types of coral etc and are done mainly with powerheads.
Sump return is a bit different. Sump return rates are calculated in how many times it reruns to the tank. Too low the sump becomes stagnant to high detritus won't stay in the sump and it's generally thought won't have time to absorb into the live rock and macro in a fuge.
Also in designing a system if it's too fast the overflow from the tank and any place the water needs to travel can be overwhelmed and flood pumping the water all into the display and on the floor faster than it can return to the sump. Standard tank overflows are Rated in gph for this reason.
The rule of thumb is
total system water volume x return rate desired = gph of pump needed. And overflow capacity.
I.e. 30+10 = 40. X 5x return rate = 200 gph pump and overflow needed.
Return rates vary by user some fast some slow. Seems 4 to 10 x return is the margin most going for 5x.

That said your design is stinking cool. I would be concerned only in the fuge sump water flow separation that the main water Flow will not flow as well as into the sump and bypass it. And the pump is overrated to the overflow and plumbing.

 

[West1]

Wow thx for the info. Im new so I'll be looking to start with the easier stuff like a few Zoas, green slimer and some other one that looks like a disc (forgot the name).

I did a test run on my tank today to see how it goes (was leaking because it was very lose and not glued). Im not so sure im getting near 800gph.

The test run


Strength of water

Does this look like 800gph? Looks a little weak to me. It's about 2.5 feet of 3/4 pcs with 4 total elbows. Fluval sp2 claims about 950gph@ zero head.

 

[saltyfilmfolks]

Wow thx for the info. Im new so I'll be looking to start with the easier stuff like a few Zoas, green slimer and some other one that looks like a disc (forgot the name).

I did a test run on my tank today to see how it goes (was leaking because it was very lose and not glued). Im not so sure im getting near 800gph.

The test run


Strength of water

Does this look like 800gph? Looks a little weak to me. It's about 2.5 feet of 3/4 pcs with 4 total elbows. Fluval sp2 claims about 950gph@ zero head.

Haha it's pretty tough to eyeball gph. 200 or so you should have will be a really soft push on your hand 800 you'll feel.
I'm glad it went well.
Somewhere here on the inter webs there are good aquarium calculators to check head with pipe size and length. But personally I think your better off under 800.
Fwiw my 55g is just under nine x return with an overrated over flow. The return back in to the tank is pretty strong and will blow sand around. I had to split the return with lock line and am trying to find time to replace the pump with the variable one I bought two months ago.

 

[West1]

Well this was just a test setup. I thought the gph would be strong enough to push water through the pvc going over my tank as well (longer video). I did notice when I start the pump, as the water raises just past the bulkheads, the return bulkheads have bubbles. I'm thinking I should run 3/4 pvc and where the T is to both bulkheads, I should reduce it to 1/2.

As per gph for the sump/tank, I was under the impression that coral need high gph. I figured why not just place a large return pump instead of having koralias on the glass. In my sump design, I figured I would have a lot of water volume going through the sump. I have the open area on the bottom so the fuge does not see the volume the pump needs. Is this a bad idea? I had posted a couple threads for help and did not get any feedback, hence the fluval sp2 purchase.

 

[saltyfilmfolks]

Yea no sweat. That's the flow return rate vs in tank turnover. My above is the standard accepted method. Esp for the return of detritus to the tank. You want to keep it in the sump.

Flow for corals is more about helping them feed and breathe. So most set the return and then can choose different heads depending on the type of coral and ther flow needs. That's hard to do if the coral flow is set by the return.
BUT
In small all in one tanks (AIO) like the Jbj nano cubes they do combine the two to a small extent. Most add a head in the tank any way as corals also prefer a turbulent flow as opposed to laminar. So yea. Your set up might be just fine as you have two in tank returns and it look like you may run filter socks too. The only thing would be if the flow is too much. You may want to add a valve to choke the flow a bit to adjust it. That's an easy Google.

Oh double check your sump design against other ones is there a bubble wall or baffle? And where does the skimmer go?

 

[West1]

I see what you mean about the return pressure.

As per the sump question, I was planning to put a sponge along the bottom section, about the width of the fuge.
I read mixed reviews about a skimmer but I figured with the return chamber size, I could place a skimmer in the bottom right corner if I went that route. I do like the glass mame skimmers as they are small. I might try them when the time comes.

 

[West1]

Looking at the fluval flow chart, I am between 459-581 gph. Makes sense now on the flow pressure. So I guess im pretty close to an ideal gph after all. I want to try and avoid using any wave makers/koralia, I do not like the look of them. If need be, I'll drill another bulkhead in the back of the overflow and have the return connected to the tank instead of the sump.