New return pump installed

[jhendu]

So my new mag-18 came the other day and I finally got the time to install it this morning. It turned out to be a bit more of a project than I though it would be. The physical installation was a snap. I jsut had to throw together a new fitting on the pump end of the plumbing as I had planned ahead a bit on that part. The flow created by the mag-18 over the mag-7 is clearly night and day. Where I ran into issue was water levels/drain rates. THe durso immediatley started "flushing". It just wasn't keeping up with the 18. After trying to tweak several things I ended up drilling an extra vent hole (1/16") at the top of the durso. This seems to have fixed that problem. Now the only thing that has me a little concerned is the tank water level. The water level is at its absolute maximum. The water flows over the top of the overflow and not just through the teeth. While at the moment it seems to be doing fine, that is higher than it was with the mag-7 on there. I'm sure that I could valve down the return line from the pump but I don't want to do that. I want the max possible flow. Should I worry or just let it ride?

 

[Kentanner11]

I would let it ride for a few weeks maby a few months letting the pump "slime-up" performance of pumps change greatly after this period.

 

[JohnnyM2]

Seems you went from a 675 gph pump with a 12.5 ft head to a 1800 gph pump with a 22 ft head. If your are running this pump with a 45 ft head, which is typical for a self contained tank and stand, and using a single durso, it seems you are overloading your drain and can expect a flood in the near future. Valving down stresses the pump but a small restriction is, I suppose, no worse than higher head pressure. Can you tee off your return with a ball or gate valve and return part of the mag 18 effluent to your sump? My guess is that with that pump you are generating unnecessary heat, wasting energy and setting up for a flood. I think I would go for a smaller pump. There is lots of room between the Mag 7 and the Mag 18.

 

[cerreta]

Jason, the pump is fine. You need to fix this problem now, don't wait.

You drilled the hole in the Durso cap too large.

Place your finger over that hole and give it a minute. You will see that the drain will work faster and the slurping sound will return.

The trick is to make a hole just large enough so that water rises above the water inlet to stop the slurping, but no higher. If the water level gets higher, like it is now, then the potential for flooding occurs.

I like drilling a 1/8" hole into the side of the cap so that the hole penetrates the cap and the PVC under it. You can then turn the cap, thus changing the size of the hole to fine tune the air entry in the pipe. Look at my build thread for an example.

If you are unable to do this because the pipe is already installed, then remove the cap and drill a hole large enough to insert an air line bleeder screw. This screw will allow you to fine tune the air entry. I don't like using these, because the cheap green ones are tempermental and will fail over time, plus they stick up higher and look ugly.

Just remember this:

Big hole = Big Air = slow draining = flood

Small hole = Less air = fast draining = slurp

 

[jhendu]

Thanks Scott. I'll try that approach when I reinstall the 18 tomorrow/this weekend. In order to avoid any issues I put the 7 back on the other day. My cap comes on easy so worst case I'll just replace it. I'll let you know if it works.