Hi Fawn.
I have a suggestion on how you could plumb your tank. I like a silent tank, so I came up with this idea and it works really well. You will have no sound and no bubbles and 100% flood protection, all in one!
You have a 3/4" and 1" hole in each overflow.
1st: Make a drain to the sump using the 3/4" holes. Make the stand pipe in the overflow go up about 75% of the way up (maybe 8" or so from the top of the overflow). Put a ball valve on the drain lines and run the lines into the sump.
2nd: Make a drain to the sump using the 1" holes. Make the stand pipe from the 1" hole go about 1" or less from the bottom of the teeth in the overflow. Run the drain lines into the sump with no ball valves on them.
3rd: Take the return line coming from your return pump and run it over the back of the tank. I like to split it in a "Y" so I can get a return on each end of the tank. Here are a couple pics. I have since updated the method, but you get the point from these.
Make something similar to this. You will have two of these if you split the return into a "Y".
Remember to put siphon holes in the returns
Operation: The 3/4" shorter standpipes in each overflow, flood with water. This results in no noise or bubbles in the sump since the lines are 100% filled with water. The water then rises inside the overflows until it goes into the higher 1" drains. The water level in the overflow is just under the bottom of the teeth so you get no noise from falling water.
The trick is to adjust the ball valves on the 3/4" drains so that the water going into the 1" drains at the top is just a trickle. Its such a small amount of water that goes into the 1" drains that there is no noise and no bubbles in the sump. It might take a few minutes to adjust everything properly, but once its adjusted, you dont have to mess with it much after that.
Flood: The flood prevention is that if at any time one or both of the 3/4" "main" drain lines get blocked, the two 1" drain lines (that hardly have any water going down them) can handle all the water that would normally flood your house. I have actually had snails clog my 3/4" drain lines a couple times and this method saved a flood. You cant go wrong with 4 drain lines!
Tip: I acutally used a durso system for the 1" drains since I had them laying around the house. Ive done it without the durso's and it works fine, but I do like the durso method better. You are really not using the durso's as they are intended becasue there is only a trickle of water going through them. However, if you do have something happen where water rises and needs to escape through the 1" drains, the durso's seem to handle the water flow a little better.
Top view of the shorter 3/4" drain the taller 1" drain using a durso.
Problems: If you ever hear any noise in the overflows or see a lot of bubbles in the sump, then you know something is wrong. Its kind of like a built in warning system. If to much water is going down down the 1" drains, there will be a lot of bubbles and noise in the sump. This may indicate a blockage in one of the 3/4 drains. If its just a small amount of bubbles, then the ball valves on the 3/4 drains may need a little bit of adjusting.
If the water level in the overflow drops to low, you will get the waterfall sound and if it gets really low, you will get the toilet flusing sound from the 3/4 standpipes. This may indicate something wrong with the return pump as its not pumping as much water as it should. IF the water in the overflow only drops a inch or two, then the ball valves on the 3/4 drains may need a little adjusting.
I only have to mess with the ball valves maybe once or twice a year and that takes about 30 seconds.
This is just my method. There are other methods you can use that work also. If you have any questions, let me know.
