Thanks for all the info and I will take your advice, a friend of mine also recommended running 2 smaller pumps in case one goes out, also I like the idea of just adding 2 extra holes the same size and running 2 drains and 2 returns. Really glad you advise this and would like some others to chime in before I start drilling.
Edit think I miss read, so I should use both holes as drains and just run 2 pumps with lines over the back of the tank as return instead of drilling? Also my holes are in the middle of the sides and not in the back, I have no weir or anything. Any suggestions, was thinking of using silicone to add 3 glass panels to protect the pipe from a large fish crashing into it as a weir. I will make slits in the glass of course
YEs, I would use the two existing holes as drains.
On my tank, the back is painted, so you can't see the return of the pumps. Pipe runs up to the top of the tank and sprays the water in. The builder I bought it from had some diverters in there to spread the return flow out a bit.
It would look nicer to run the returns of the pump up through the bottom, but it's going to be very hard to drill 1" glass. I have a fish room of about 40 tanks, I drilled all with at least one hole. I used a drill press.. but my biggest tank in the room was a 125, and it was not nearly 1" thick (only 1/2" , I think).
Point is.. It's going to be difficult to do a hole on the bottom with a drill press. Not impossible.. A guy I know that did aquarium maintenance rigged a special drill press to do it.. I can give you details.
I would not want to drill a tank like yours with hand. It takes forever, and the long amount of time means it's hard to keep the hand steady. Also on a hand held drill, it's difficult to keep the optimum RPM for the diamond bit. I learned the hard way that if you spin the diamond bit too fast, it dulls quick. When the bit gets dull enough, it breaks your glass. Thankfully, I only broke a few 10 gallons before learning.. So just a long winded way of saying, maybe it's better to avoid the risk and just put the pump returns at the top of the tank, and avoid drilling more holes.
Plus, I don't remember the entire thread, but are you sure the bottom is not tempered. I doubt it is , because it's 1" thick, but you need to get a cheap polarized camera filter off ebay and check before drilling. They are only about $5. Youtube has vids. People use polarized sunglasses too, I have not tried that.
So yea, use the two existing holes for drains. Two 1 1/4" drains ought to be fine with two mag drive 950s..
wednesday13
will have some ideas. He sure knows tanks and building
