Drilling a tank inside

[TheShrimpNibbler]

First of all, if these is the wrong place for this thread, please let me know.
I’m getting ready to add a sump to my tank, but the tank is already filled. I’m debating whether or not it would be better to get an hob overflow or to drain the tank most of the way and drill it. I understand that drilling is better in the long run, but I’m curious about the safety of drilling the tank with it standing up in me bedroom. If you all can think of any ways to safely do this, I would appreciate hearing them. My only thought so far is to poke holes in water bottle lids and spray the drill, but there could easily be a better option that I am overlooking. I cannot fully drain the tank by the way. Thank you!
Edit: I forgot to include that the tank is 45 gallons and the dimensions are 3 feet long, 1 foot front to back, and 2 feet tall in case it matters.

 

[xxkenny90xx]

I assume it's a glass tank? I have heard of a few people doing this successfully but it is a very high risk low reward type of thing imo. If you start drilling and get a crack it will run to wherever there is pressure (which in this case would be where the water is). I am a Glazier by trade so I know a thing or two about glass.

I would go with a high quality hob overflow. STAY AWAY FROM CPR BRAND!

 

[TheShrimpNibbler]

I assume it's a glass tank? I have heard of a few people doing this successfully but it is a very high risk low reward type of thing imo. If you start drilling and get a crack it will run to wherever there is pressure (which in this case would be where the water is). I am a Glazier by trade so I know a thing or two about glass.

I would go with a high quality hob overflow. STAY AWAY FROM CPR BRAND!

Yes, it is a glass tank. Thank you for the advice. I was planning to go with an eshopps overflow if I go the hob route

 

[fishguy242]

hi,too risky thin glass,a spray bottle would work if you did ,need two people 1 drill 1 spray,dont!!! eshopps overflow box

 

[TheShrimpNibbler]

hi,too risky thin glass,a spray bottle would work if you did ,need two people 1 drill 1 spray,dont eshopps overflow box

If I am reading this correctly, you are saying not to use an eshopps overflow box?
So far it sounds like the risk with drilling is greater than the end reward when you can’t use a hose.

 

[fishguy242]

sorry,do not drill,yes eshopps overflow

 

[Pistondog]

Drill. Keep running water on the bit
And maybe modify the eshoppes to use a bulkhead rather than siphon, thats what I did.
It is a nice compact overflow.

 

[TheShrimpNibbler]

Perhaps I should get one of those one or two dollar one-gallon tanks from petco and try drilling them with a water bottle so that I can see if it would work or not. Do you all think that if I could successfully drill a small tank like that several times that it would be safe to try it, or would the risk be too great still.
I think I forgot to mention that there would only be about 1 or two inches of water left in the tank, but I’m not sure if that makes a difference.

 

[fishguy242]

can be done....high risk,buy a 45 ,if you try,and succeed ,return ,will have tank to replace if cracks

 

[Pistondog]

Perhaps I should get one of those one or two dollar one-gallon tanks from petco and try drilling them with a water bottle so that I can see if it would work or not. Do you all think that if I could successfully drill a small tank like that several times that it would be safe to try it, or would the risk be too great still.
I think I forgot to mention that there would only be about 1 or two inches of water left in the tank, but I’m not sure if that makes a difference.

Better plan would be to have stuff on hand if drilling fails, which it shouldn't. Like a brute container to hold livestock until you can get another tank.

 

[TheShrimpNibbler]

Better plan would be to have stuff on hand if drilling fails, which it shouldn't. Like a brute container to hold livestock until you can get another tank.

I would be emptying the contents of the tank into a brute prior to drilling, so this won’t be a problem. I guess I could always do what fishguy said and have a backup tank on hand. It’s luckily a very cheap tank so it wouldn’t be an awful blow if I did have to replace it.

 

[HuduVudu]

I just drilled my tank. It was empty though. I have to say that the diamond hole saws are crazy good. They cut through the glass like it was acrylic. I was definitely aprehensive when I started though. Here is what I can say having just done it. You are going to get glass dust around. You need to plan for that. The side opposite of what you drill will likely chip out in places ... plan for that. You can drill dry but you need to go for short periods of time and let the saw cool. Take your time and be careful. Yes, there is a chance for a crack, be prepared for that, but I think if you are careful you can do it. One more thing it is best to drill out a piece of wood first to use as a template for when you first start to cut into the glass. This makes positioning a lot easier.

That said I 100% disagree with siphons. IMO they don't work well and they are prone to failure that could be ugly. However, depending on what you are trying to do in your sump you can use a HOB to accomplish. HOB Skimmer, HOB Refugium ... you name it. Honestly if you don't want to deal with the risk HOBs will be a good path.

 

[Pistondog]

I would be emptying the contents of the tank into a brute prior to drilling, so this won’t be a problem. I guess I could always do what fishguy said and have a backup tank on hand. It’s luckily a very cheap tank so it wouldn’t be an awful blow if I did have to replace it.

If the drilling fails, how long can the fish live in the brute.
Some aquariums are brute containers.

 

[fishguy242]

high speed ,steady pressure,stay level,spray w water ,over in a minute,best advise i can give let us know

 

[Pistondog]

Clamp the wood template where you want the hole as huduvudu suggests. Remove it once the drill has scored the glass and wont walk.
Put something on the inside of the tank to catch the glass slug and shards.
Ease up on pressure when you are about to break thru.
You got this.

 

[xxkenny90xx]

I still don't like it on a running system but 1" of water doesn't seem too bad. Just make sure you catch all the glass dust and shards. Are you pretty comfortable using hole saws and drills? If not then a practice piece of glass is a good idea. Try to get some with a similar oa (thickness).

If you call around to local glass shops I bet they will give you as much glass scrap as you want. Tons of it goes into the trash.

Fwiw there are many members on here who have used hob overflows for years and years with no problems. I believe that a few bad designs have given them all a bad name (looking at you cpr)

 

[TheShrimpNibbler]

Thank you all for the suggestions. I was already planning to tape a trash bag under where I am drilling to catch the water and glass shards. I also was already planning to use a wood template. I think that I will try drilling on some scraps and then make a decision from there.

 

[Pistondog]

I still don't like it on a running system but 1" of water doesn't seem too bad. Just make sure you catch all the glass dust and shards. Are you pretty comfortable using hole saws and drills? If not then a practice piece of glass is a good idea. Try to get some with a similar oa (thickness).

If you call around to local glass shops I bet they will give you as much glass scrap as you want. Tons of it goes into the trash.

Fwiw there are many members on here who have used hob overflows for years and years with no problems. I believe that a few bad designs have given them all a bad name (looking at you cpr)

I hope most scrap glass is recycled, very energy intensive to produce, easy to remelt.

 

[fishguy242]

use 2 strips of duct tape to make 3" wide attach edge under hole ,use another piece to front glass as a strap ,to catch dust and chips,almost like a hammock

 

[Jblaine]

I drilled mine and have the Eshopps over flow. It’s a Marineland 75 gallon from petsmart. Just make sure it’s not tempered glass. You can drill tempered glass because it will shatter. Check and see if manufacturer of tank has that info. I keep hose on while drilling glass.