Siphon Break ??

Is there supposed to be a siphon beak on the underside of the 90 on top of my return line, because there is and its just at the water line an blowing major bubbles.

 

As long as you keep your Loc Line just slightly below the surface, say 3/4", so when the power goes off only that small amount of water will be siphoned back to the sump before the nozzle is exposed to atmosphere and the siphon breaks.
Drilled holes just like check valves are a false sense of security and can and will fail. They both require regular maintenance and cleaning and even then whats to stop a snail or anemome plugging the hole or a grain of sand causing the check valve to leak.

Drilled holes are used as a crutch or afterthought to make up for a poorly designed return. I would get rid of the noisy drilled hole and make sure the return is never more than an inch or less below the surface and you can sleep soundly at night. As long as you always maintain that easily calculated amount of freeboard or extra capacity in your sump it will never be a flood risk. In my case with a 100G display thats only 3.5 gallons of spare room which is easy since my skimmer does not like the sump too full anyway.

 

I plugged the hole, and will probably just keep the nozzles just blow the water level.

 

+1 to this and glad to hear you have kept the return nozzle close to the surface.

 

LOL!!!

I took over a store that plumbed return lines from the bottom (i.e. not in the overflow box). There were 2 850g tanks and 2 250g tanks plumbed this way.

ME: we need to plug those, rip out the plumbing, and re-route the returns.

OWNER: No we don't. See, we installed check valves.

ME: Those check valves aren't worth diddly-squat

OWNER: Curt, you are always trying to find ways to spend money. I know more about this than you do.

ME: Steve, you're going to regret this. I've been doing this hobby a lot longer than you.

OWNER: Well, I'm the boss.

It wasn't more than a couple weeks later that we had a thunderstorm. End result, 2200 gallons of water on the floor. Some of the check valves worked but at least one failed per tank. :

 

So its better to have the piping at the right height to avoid an overflow, instead of using a siphon break to prevent an overflow.

 

:thumb_up:

 

Absolutely.
Drilled holes get dirty, plug, get covered by a snail, fish, anemone, food, algae etc. The end of a return placed at the correct height requires zero maintenance and its impossible to flood once they are exposed to atmosphere since water cannot jump uphill.

Even if you cleaned a drilled hole every day, that is no guarantee a snail won't be over trhe hole doing its job when the power goes off 5 mimutes later.

Check valves are even worse.

 

So I plugged the whole on the return and have the nozzle set to where they will not overflow the sump.

I also had a siphon holes on each side of the top of the drain pipi, the water level wasn't high enough to completely cover them causing a gurgling noise, so I increased the size of the hole at the very top of the drain pipe which raised the overflow water level just enough to cover those holes.

The last thing I need to figure out is the air bubbles in the sump from the force of the water from the drain. I have two thoughts, first I could use a filter sock which I hear works however I never really planned on using them, the other idea is to put a series of 45s at the end of the line to slow down the flow.

Kind like this