Safe to just... plug drill holes?

[Hybridfish7]

Found a 180 for really cheap but it has 2 overflows with bulkhead holes in the bottom of the tank. I can understand just plugging the holes if they're in the back of the tank, but is it structurally safe to plug them with bulkhead fittings if the holes are on the bottom? I just want to be sure. I know logically speaking it's about the same as if you had actually had pipes running through them, but yknow.

 

[Midwater]

Could you silicone a square piece of glass over the holes on the inside of the tank?

 

[Kilograms]

Structurally it will be fine whether you use a blanking cap on the pipes but as stated , a glass plate siliconed over the holes would be better. It's a 180 so to be safe I'd use 10mm glass to cover over the holes. Just make sure the surface is cleaned properly before you apply

 

[wednesday13]

Perfectly fine/ normal in my opinion. Right now i have a 500g same thing. I just switched out to uniseals and capped pvc. Before that i had regular bulkheads and ball valves. It can come in handy for water changes if needed. You can also use a return pump through them with a check valve or even plumb a canister filter through the holes. Also had a smaller 60ish g tank with an ehiem plumbed into bottom bulkheads. Reefer guys do closed loops all the time in the same fashion. Can use the holes to ur advantage or just glass over with silicone as others suggest aswell.

 

[Deadeye]

I just used bulkheads for my 125, and then put a healthy amount of silicone around just to be safe. Knock on wood still doing well 2 years later.

 

[jjohnwm]

Another vote for using a capped-off bulkhead. Installed with silicone as well as the rubber gasket, it'll last longer than you could hope for, and that way you'll always have those holes available to you for some future re-design.

Sealing with a piece of glass is also easy and works perfectly, but...someday, sometime, you will find yourself looking at that patch job and thinking "Dang! I wish I still had a bulkhead there!"

wednesday13 , how long have you been using UniSeals? Do ya trust 'em? Do they last? I find them very tempting, but...they just seem too good to be true.

 

[Milingu]

Bulkheads tend to leak at some point. Usually because the rubber seal becomes porous. You want to be able to replace the rubber seal without any issues, so I would never seal it with silicone.

 

[jjohnwm]

Bulkheads tend to leak at some point. Usually because the rubber seal becomes porous. You want to be able to replace the rubber seal without any issues, so I would never seal it with silicone.

Agreed, the rubber gaskets with which most bulkheads are equipped often last only a few years, although that's a quality issue; some of them are much longer-lived.

I know that "common wisdom" scoffs at silicone on bulkheads, but I have done it regularly with excellent results. Even if/when the rubber degrades, the silicone continues to function as a seal. I currently have a half-dozen or so "double-sealed" units like this that are now in their 14th year of continuous operation and are still perfect. In my previous home I had many more that were much older, some on tanks that had been emptied/moved/re-filled multiple times. A generous bead of silicone right onto the gasket, a thorough tightening of the bulkhead, and then an immediate quick finger-smoothing of the squeezed-out silicone...just like assembling an aquarium out of glass pieces siliconed together...and you have a seal every bit as permanent as those holding the tank together. IMHO it's far superior to a rubber gasket with a (usually) much shorter lifespan.

You want to be able to replace the rubber without issues if you need to; using silicone, you won't need to. The minor inconvenience and sloppiness of doing the install with silicone pays off in the long run.

 

[Hybridfish7]

Thank you everyone for the tips, it looks like (if I can now find a rental truck in the next few days), I'm getting a 180.