Overflow Question...

[untaken_moniker]

Hi all, first time poster here although a lot of what I have learned about this hobby in the two years I've been involved has come from lurking this forum.

I'm two years deep running a 90 gallon FO, without a sump. All is well but the constant water changes are a major pain, so I've decided to step up my game and install a sump. I have the sump built and purchased a skimmer, ready for drilling and plumbing. My question is about OVERFLOWS. Are they really necessary? Is there any reason I can't drill and install 1" bulkhead (s) that drain directly from the tank to the sump without an overflow? There are obviously benefits to using an overflow, but I've done copious amounts of googling and am still left wondering if it's really worth the added expense. School me Reef Central!!! ...please

Any advice would be greatly appreciated

Cheers,

Doug

 

[Dr. Reef]

my dual qt tank setup has no over flow. just a bulkhead drilled and placed with a strainer in the tank side and pvc pipe draining constantly to sump from both qt tanks. i have had no issues.

 

[Ron Reefman]

Are you planing to drill the bottom of the tank or the back of the tank?
How far down the back (assuming this is where you are going)?
Do you plan any structure (pipe, strainer, whatever) inside the tank attached to the bulkhead?

The reason for an overflow, as I see it, are to allow drilling the bottom of the tank rather than the back, therefore allowing the tank to be fit closer to a wall. It also creates a barrier to the entire tank draining into the sump (assuming bottom bulkhead and no overflow). It also allows for the water level in the tank to only be lowered a little before the overflow stop draining and then one could work on bulkheads without water behind it.

There are lots of ways around using an overflow. Some are very effective and some prone to a host of 'issues'. Choose wisely.

 

[untaken_moniker]

Drilling the back of the tank as high as I can get away with as not to affect the water level too much. Planning on a bulkhead (or two) with a strainer. My LFS is telling me if I install bulkheads without an overflow the water level will be too low. I disagree with him but I want to make sure it's doable before I commit. I'm far from an expert but can't wrap my brain around how it wouldn't efficiently work without an overflow.

 

[Rybren]

Without an overflow or upward turning elbow, the water level will somewhere around the middle of the bulkhead, depending on how much flow you have from the return pump. It will also likely be fairly loud unless you have minimal flow.

As I see it the two biggest reasons for using an overflow box are:

- to restrict the amount of water draining back to the sump on power loss
- surface skimming

Just my $0.02 worth.