Refugium Help!

[salty]

I have an extra 5 gallon tank, and as it would be a waste to not use it, I'm going to try to make a refugium out of it! Not a sump. Just a refugium. The placement of the refugium is at the corner of my stand, so fiddling with the equipment would be difficult. So the real issue I've been having is connecting the main, 10g tank to the refugium. I don't have the resources to do an internal overflow, so what would be the best way to connect the two aquariums? By using two pumps, everything would need to be perfectly synchronized. And what about using a siphon? Some say the siphon will break down eventually, so what is the solution to all this? Any help would be appreciated

 

[bcavalli]

With my old refugium I split the drain pipe and valved the refugium drain.  On the refugium it sat higher than my sump and it was drilled in the upper rear corner.   Then it just gravity fed into my sump.  Pretty simple design and is pretty much failsafe.

 

[saltwaterwannabe]

Maybe someone with a bit more experience can weigh in, but I would be very hesitant to rely on using two pumps to mimic an overflow system since it would be nearly impossible to dial them into and maintain the exact same flow rate.  If the flow rate does not match, you will either have an overflow in the sump or an overflow in the DT with a burned out pump and overheated sump once the pump runs dry.

If you cannot do an internal overflow, I would go with an external overflow, although I have never used an external overflow personally.

I have built a very inexpensive overflow style setup for very little money before to use for a QT, and still have it today.  I drilled the back of a tank with a $5 hole drill from Amazon, added two 1/2" bulkheads and short section of vinyl pipe to the sump, then a small return pump.  Not quite the same as a bonafide internal overflow, but it is not far off the mark.  I used a tee inside the tank with an elbow 1/4" higher to provide a backup overflow that I have yet to see used unless I dump a lot of excess water directly into the DT.  While the tee and elbow overflow are not particularly attractive, it does function well with a gurgle every couple of hours.  I used two tanks from the Petco sale and the rest was stuff I had on hand already.  I think I have about 40 bucks in the entire system excluding the pump, bulkhead, and heater which I already had.  I did look at some internal "shadow style" overflows, but did not wish to fork over the money for one at that time.  The "shadow style overflow" is an easy upgrade to the add to the inexpensive tank and looks a lot better than a traditional overflow with hole through the bottom of the tank in my opinion.

 

[saltwaterwannabe]

I see I started typing before Brett responded.  Do you currently have a sump?  If so then Bretts' option would be a breeze.

 

[salty]

No, I don't have a sump, unfortunately . How does sump's plumbing supposed work, actually, if there is an internal overflow? How does the water level stay even? How does the amount of water going in and out be the same??

 

[bcavalli]

Basically the water drains from the overflow down to the sump via gravity.   The size of the tank (the water volume) and the distance from the sump back to the tank, determines what size return pump you will need (there are a few other variables).

There are a few options for overflows.  Built in overflow with a weir (your tank must be drilled in the bottom), hang on the back or an overflow box which is drilled near to the top.

 

[danh]

Trying to synch two pumps is a bad idea. Don't do that. I would use it over the main tank.. If you can find a way to hide the pump in the 10g pump it up to the 5g. Drill and overflow hole in the 5g that drains back to the 10g.

 

[salty]

Any reccomended place to get an HOB overflow? I’d like to DIY an overflow using a u-tube and some piping.

 

[danh]

You can make your own with some PVC. I ran a 30g freshwater tank in to my 180g sump with pvc overflows. If you can put the 5g above the 10g all you need to do is  drill a hole, add a bulkhead and a little bit of pipe back to the 10g. You can just place the pump right down in the 10g.

alt="abovetankfuge" />

 

[bcavalli]

If thats the route your going with then I would recommend doing some reading.  HOB overflows potentially can have issues.   What size is your tank?

 

[danh]

alt="2vukm54" />The DIY overflows are big and ugly... but cheap....

 

[danh]

A better picture

alt="P1030073" />

 

[salty]

The main tank is 10 gallons, and the refugium is 5. Could I use this as my siphon?

https://www.marinedepot.com/CPR_Inflow_Kit_3_4_inch_Returns_Plumbing_Parts-CPR-CR1385-FIFTRP-vi.html">https://www.marinedepot.com/CPR_Inflow_Kit_3_4_inch_Returns_Plumbing_Parts-CPR-CR1385-FIFTRP-vi.html</a>

Is there a return pump that pumps such a small amount of water? To confirm, the siphon has to put in the same amount of water the pump puts back in? What about the HOB filters with a backup siphon? Same flow?

 

[danh]

You can't use that as a siphon.. the amount of water going in to the 5g must be EXACTLY the amount that is being pumped back.  A Siphon like that will never do that.

To work like a hob, do it like the diagram I posted.

 

[saltwaterwannabe]

With an overflow setup, the overflow can only return as much water as is pumped to it so the flow will always balance unless the flow from the pump is way too high for the weir, resulting in drilled tank overflowing.  Ie if you put a 1000 gph into your setup, which is way too high so the upper wier would not likely handle the flow.

You have to make sure to account for the volume of water that will slowly drain from the upper tank if the pump is turned off.  This basically means you leave the water level in the lower tank a bit low to allow space for the extra water that will drain until the upper tank water height matches the weir height.  When the water is running at a constant rate and height in the tanks, measure the depth of water fromthe lowest point it passes over the wier to the top of tbe water.  This depth times the surface area of the upper tank is the volume you need to leave available in tbe lower tank.

The volume that will drain down is dependent upon how long the overflow wier  is and the pump rate.  Basically, the flow area over the weir is the length of the weir times the depth.  There is a way to calculate the flow area, but it is a lot easier to just adjust the flow out of the pump if it is too high with a valve or smaller pump.

I would drill the 5 gal if you can hide it with the hole slightly above your dt water surface height.  Otherwise I sould drill the 10 gal and put the 5 gal belown which leaves the pump out of your dt.  The pump would be placed in the undrilled tank either way.

 

[saltwaterwannabe]

Also, I would trade you a drilled 10 gallon for your 5 gallon if you can wait a few weeks and drive to Holly Springs or Marietta.  You would need 0.5 inch bulkhead(s) (about 5 bucks) and some form of weir, which I can show you how to setup for a few bucks in fittings as well.

 

[salty]

AUGH! I really want to do it, and my refugium would be bigger, but my stand definitely wouldn't allow. I use a Kallax 4x4 unit, and the 5 gallon tank overhangs by half an inch. Unless there is a tank switch, I don't think it can be possible. We can still talk in PM. I'd still like to make the trade, just in case.