Drainage question ~300 gallon

[Lamball1]

My next tank (i'm going to move) is going to be in the neighbourhood of
~300 gallons so I'm trying to find as much out as I can before I start my journey.

What would be better (in general), two inbuilt overflows on each side or several bulkheads to drain the water back to the sump. Also, for a 300 gallons, what sort of sump volume would be appropriate? I was thinking of a 90 gallon?

[BeanAnimal]

A Coast-to-Coast style overflow would be a good choice. Sump volume depends on the desired function of the sump.

[pmrossetti]

Will you have access to the back of the tank? If not, you can access internal overflow plumbing from underneath.

If yes, top drilled bulkheads offer more safety. If you don't mind seeing external plumbing.

All my tanks were against a wall, so I opted for int. oveflows. Always positioned so bulkheads were over my sump.

I always used the biggest sump I could fit, always leaving room on the side of it for an ATO container. so for a 6' tank, used approx. 4' sump.

hth

[Lamball1]

Thanks, for the comments. Why are top drilled bulkheads safer?
And what exactly is a coast to coast overflow?

[pmrossetti]

top drilled holes can NEVER drain your tank, more than a few inches.
bottom holes can if there's a flaw in the overflow box seam.

ctc is an overflow that spans the top rear of the tank, side to side.
inside or outside.

[viggen]

I have always preferred one properly sized overflow (big enough to give proper turnover) in a back corner of the tank. I have had several dual overflow tanks & I do not like the way it looks, harder to hide.

My 475g uses one overflow in the back corner of the tank. So when I feed the fish the food has 11 feet to travel before it gets sucked into the overflow. Thus another reason I prefer one overflow. The coast to coast style would keep any stuff from collecting on the top of the water however like mentioned I think a lot of food would get sucked into the filter. Which probably depends on what you keep int he tank thus type of food.

[BeanAnimal]

So when I feed the fish the food has 11 feet to travel before it gets sucked into the overflow. Indicating how poorly the surface turnover and skimming are :)

Turning off the return pump is a common feeding method :)

[JohnM99]

I think an external coast to coast is ideal. An internal coast to coast is probably next best. If you have to do a bottom drilled overflow I would certainly agree one is better than two, but the surface skimming is much better with a coast to coast, and it interferes much less with your aquascaping.
I made the mistake of making a much-too-big internal bottom drilled overflow, which I am going to get rid of (either by breaking down and redoing my tank, or getting a whole new one). I have been researching this to death - and I think if you follow BeanAnimal's advice you won't go far wrong. (only question I have, how on earth can one human write 19,168 posts!!! Yikes!).

Depending upon your situation, I have seen some very nice setups with an external overflow on one end, rather than on the back. That can give some interesting flow dynamics.

[Lamball1]

bulkheads vs coast to coast overflows in terms of noise.
Which one wins?

Also, now that I'm here, what speed return pump would be appropriate for a 300 gallon?

[JohnM99]

2 sources of noise -
1. water falling into overflow
2. water going down pipes

2. can be eliminated by using a siphon technique such as BeanAnimal or Herbie.
1. isn't talked about much - and bother me - depends on distance to fall, whether sides are sloped, etc.

[Lamball1]

So which one would you recommend? I'm a DIY n00b and just have to be sure someone can build it for me properly