Fishy!'s Long and Low 60ish Gallon

[Myka]

Originally Posted by Fishy!

Good point. I had not thought of it like this. I was hoping to have a net 600 gph going through the sump. I guess it's just a matter of aesthetics for me. Where would I place a single return on a solid back wall? Maybe in the middle, with the two powerhead in each corner. Something to think about.

For mine, the drains are where your returns are, and the return is in the middle. You could just keep the layout how it is, and pick one side or the other for the return.

Originally Posted by Fishy!

Tank with overflow is 69 gallons. I was hoping to have 20-30 gals of water in the sump ideally netting out at 100 gallons. I will have to be careful to leave enough to back siphon room in the sump for approx 5 gals. (40" tank width X 4" overflow depth X 6" height of full siphon below water level). That doesn't account for any back siphon of return lines or the volume of water held in the actual plumbing. I'm afraid I will need a pretty tall sump. This might exclude me from any pre-manufactured sumps out there. Thoughts?

Thanks for your feedback. Keep it coming.

I don't know what the heck I did to typo the tank volume, since I just redid it and can't come up with 61 gallons again.

The main drain in the back chamber (the one with the gate valve on it) has a standpipe on it which is 2" lower than the emergency drain. When the system is turned off it only drains a little over 1 gallon down to the sump.

However, I did design my sump to hold the entire back chamber volume which is 11 gallons (at operating level). My sump is 24 x 20 x 16", but there is an RO chamber along one side so the actual sump area is 20 x 19.5 x 16" which is 26 gallons if it's full to 15.5" (minus glass widths of baffles and such). With the tank running, the water in the sump is 8.5" deep which is 14.5 gallons. Add that 14.5 gallons to the 11 gallons in the back chamber (should it ever fully drain to the sump) and you have 25.5 gallons which fills the sump to 15". This sounds ok, but then there's the backflow from the tank/piping and the volume from the skimmer when it's off...

After all this planned redundancy though, I did my calculations with the back chamber being 3" wide (which is what I ordered), and I was surprised when the tank arrived with a 3.75" wide back chamber and my sump was already built. So, my sump won't hold the backflow from the tank/piping, the backflow from the reactors/skimmer/etc because the back chamber holds 2 gallons more than planned. If the back chamber was 3" as planned, then it would have all worked out.

You just have to plug numbers into an aquarium volume calculator and figure out how big your sump needs to be. Don't forget to take glass thickness into consideration. You need the inside measurements. Also, I don't know the water depth for the skimmer you picked. I made sure the skimmers I bought didn't need deep water. Some need 11" deep water, and I just didn't want that extra volume down there.