need help drilling acrylic

[bradsark]

I am interested in drilling a couple holes in my acrylic tank for a closed loop. Since it is currently full of water I was thinking of drilling down through the top and running pvc down from the top and into the water. Does anyone see a problem with this type of closed loop design?

Also, will I weaken the top and cause structural problems with the tank?

How far away from the edges should the holes be?

What type of drill bit should I use for a 1 1/2" hole?

Any other input would be great.

 

[skipm]

I thought that the idea of a closed loop was to keep the circulating pump and plumbing out of site as much as possible while still adding extra current. I would reccomend against drilling in the top of the frame because removing 1 1/2" of acrylic will weaken the top extensively. You didn't say what size tank you are talking about so I have no idea about how much of a problem we are talking about to drain the tank down about 1/2 to 3/4 of the way and then drilling the holes lower in the back wall of the tank. As far as the best way to drill the 1 1/2" holes, I have had success using a fine toothed hole saw and drilling at a slow rate (let the saw do the work without forcing it). Good luck, Skip

 

[bradsark]

it is a 150 gallon tank. I was concerned about drilling below the water level because I don't want to destroy the entire tank if I screw up drilling the hole.

 

[Anonymous]

I don't think you will have any problem drilling the top of your tank. I have done it bunches of times, and seen stores do it bunches of times. Idealy, you would also do it with the tank empty, but I have also done it on full tanks. Use a hole saw and go slow. Your tank should have some equipment slots along the back, and I would put the holes that far away from the edge.

If you plan it right, you can drill the holes in the right place as to hide the plumbing behind the rock work. I have 2 closed loops on my tank that come from above, and you cant see them at all. I actually don't like to have holes drilled in the back of the tank because it makes them hard to get to if you nedd to.

Of course, there is always a risk when you drill a tank...but I would take it.