180g planning -- please help

Delphinus88 · 09/09/2014, 08:23 AM

I just purchased an Oceanic 180g. This comes with 2 HUGE overflows and 4 holes on the bottom of the tank. My current plan is to remove the two 9x11x24 overflows, drill the back of the tank and install a coast to coast and use a Bean fail safe.

1. Do I need to set up 2 sets of bean meaning 6 holes plus the returns or will one set suffice? Right now my intent is to have a mixed reef but don't want to be limited later down the road by low flow rates.

2. The holes on the bottom scare me. On the forums I hear too much about cracked bulkheads. It seems that would be catastrophic with the bottom drilled as opposed to only losing a couple of inches of volume if repair was needed. What are the options? Can I just take a 9x11x ½” slab of glass and silicone it on top to close it off?

3. What are the advantages/disadvantages to internal/external overflows?

Any other suggestions are also welcome. I would like to avoid the "why didnt you do .....?" later
Thanks

JMorris271 · 09/09/2014, 08:40 AM

Good point about the cracked bulkhead. That's why I will have the sump and the TO underneath the BHs.

thegrun · 09/09/2014, 08:42 AM

1. As long as you size the holes correctly for the desired flow, you only need one set of holes.
2. You are fine to silicone a piece of glass on top of the existing holes. Be sure to allow enough time for the silicone to fully cure (two weeks minimum).
3. If I understand your question correctly, I assume the tank is drilled in both scenarios (internal or external/behind the tank). With internal overflows you give up inside the tank space, but the tank can sit close to the back wall. With an external behind the tank overflow you gain space in the tank, but your cabinet and tank need to be placed off the wall to allow room for the plumbing.

Delphinus88 · 09/09/2014, 08:49 AM

I'm not too worried about space behind the tank as it will be in the wall and a small fish room will be made in the garage. Is the surface skimming that you get from a coast to coast better than what you would get with the external overflow and does it make a measurable difference?

thegrun · 09/09/2014, 09:26 AM

IMHO if you set up your overflow and drains correctly both work fine. That said I'm just starting to set up a new tank and it will have a coast to coast overflow.

GroktheCube · 09/09/2014, 09:31 AM

Internal is probably a little bit easier to do on an already built tank, as it involves a little bit less cutting/drilling/gluing.

09/09/2014, 08:23 AM	#1
Delphinus88 Registered Member Join Date: Jan 2013 Posts: 17	180g planning -- please help I just purchased an Oceanic 180g. This comes with 2 HUGE overflows and 4 holes on the bottom of the tank. My current plan is to remove the two 9x11x24 overflows, drill the back of the tank and install a coast to coast and use a Bean fail safe. 1. Do I need to set up 2 sets of bean meaning 6 holes plus the returns or will one set suffice? Right now my intent is to have a mixed reef but don't want to be limited later down the road by low flow rates. 2. The holes on the bottom scare me. On the forums I hear too much about cracked bulkheads. It seems that would be catastrophic with the bottom drilled as opposed to only losing a couple of inches of volume if repair was needed. What are the options? Can I just take a 9x11x ½” slab of glass and silicone it on top to close it off? 3. What are the advantages/disadvantages to internal/external overflows? Any other suggestions are also welcome. I would like to avoid the "why didnt you do .....?" later Thanks

09/09/2014, 08:40 AM	#2
JMorris271 Registered Member Join Date: Feb 2014 Location: Foothills of SC Posts: 2,010	Good point about the cracked bulkhead. That's why I will have the sump and the TO underneath the BHs. __________________ 120 gal mixed tank. Lightly stocked now but....

09/09/2014, 08:42 AM	#3
thegrun Registered Member Join Date: Dec 2008 Location: Garden Grove, Ca Posts: 17,023	1. As long as you size the holes correctly for the desired flow, you only need one set of holes. 2. You are fine to silicone a piece of glass on top of the existing holes. Be sure to allow enough time for the silicone to fully cure (two weeks minimum). 3. If I understand your question correctly, I assume the tank is drilled in both scenarios (internal or external/behind the tank). With internal overflows you give up inside the tank space, but the tank can sit close to the back wall. With an external behind the tank overflow you gain space in the tank, but your cabinet and tank need to be placed off the wall to allow room for the plumbing.

09/09/2014, 08:49 AM	#4
Delphinus88 Registered Member Join Date: Jan 2013 Posts: 17	I'm not too worried about space behind the tank as it will be in the wall and a small fish room will be made in the garage. Is the surface skimming that you get from a coast to coast better than what you would get with the external overflow and does it make a measurable difference?

09/09/2014, 09:26 AM	#5
thegrun Registered Member Join Date: Dec 2008 Location: Garden Grove, Ca Posts: 17,023	IMHO if you set up your overflow and drains correctly both work fine. That said I'm just starting to set up a new tank and it will have a coast to coast overflow.

09/09/2014, 09:31 AM	#6
GroktheCube Registered Member Join Date: Dec 2012 Posts: 2,063	Internal is probably a little bit easier to do on an already built tank, as it involves a little bit less cutting/drilling/gluing.