Internal overflow box

[blooper01]

So I am drilling my new tank and plan on having 2 overflows with 1 return (never done a drilled tank before, just over the top overflow). Do I have to have an overflow on the outside of the tank, or can I do everything with an internal surface skimmer box? I plan to leave one bulkhead open (with a scream), then use a 90 elbow with a short stand pipe for the emergency drain. Is this going to work, or do I need to do this in an outside the tank box? Just trying to do everything right I attached a diagram of what I have in mind, I am not an artist.

 

[Reefacist]

How big is your tank? I’m assuming it’s not too big since you have only one return. Would you want it to take up space in your tank? That’s the question to answer or else yes as long as it has a water tight seal around it you can do inside or outside.

 

[blooper01]

How big is your tank? I’m assuming it’s not too big since you have only one return. Would you want it to take up space in your tank? That’s the question to answer or else yes as long as it has a water tight seal around it you can do inside or outside.

Tank is a 150

 

[Reefacist]

How many inches is your drain? And how much water do you want to cycle with the return?

 

[blooper01]

How many inches is your drain? And how much water do you want to cycle with the return?

I have 2 1" bulkheads for the drain and 1 1" for the return. I have not drilled anything yet so changes can be made if needed. Not sure on the flow yet, my return pump is rated for 2500 GPH at 4' head.

 

[Reefacist]

I have 2 1" bulkheads for the drain and 1 1" for the return. I have not drilled anything yet so changes can be made if needed. Not sure on the flow yet, my return pump is rated for 2500 GPH at 4' head.

I think 1” drain should be fine. I would go 1.25 or 1.5 if you can. But return of 1 1” is too little and your running the risk of no return flow/flood if one return is clogged. I would do 2, 1” returns with a 1.25” drain and at least 1.25 emergency

 

[blooper01]

I think 1” drain should be fine. I would go 1.25 or 1.5 if you can. But return of 1 1” is too little and your running the risk of no return flow/flood if one return is clogged. I would do 2, 1” returns with a 1.25” drain and at least 1.25 emergency

So do 2 return pumps?

 

[blooper01]

I think 1” drain should be fine. I would go 1.25 or 1.5 if you can. But return of 1 1” is too little and your running the risk of no return flow/flood if one return is clogged. I would do 2, 1” returns with a 1.25” drain and at least 1.25 emergency

I have the 1" bulkheads and special colored PVC to match my sump, guess I screwed up