How to prevent a back flow on this...

[Calmwaters]

Hi, I was originally using a external pump for this set up but deciding on changing to submersible but I'm thinking of how to prevent it from siphoning back I know we could install a check valve but it will lessen the the GPH is there any advice you guy's can share.(Sorry for the crapy picture)

 

[fourty2]

the only thing i can think of is making a small hole in the water outlet pipe,above the main tank water line...so if the pumps fail you wont have a vacuum so no back syphoning....cant really explained very well what i mean,hopefully you can understand my ramble.....

 

[West1]

the only thing i can think of is making a small hole in the water outlet pipe,above the main tank water line...so if the pumps fail you wont have a vacuum so no back syphoning....cant really explained very well what i mean,hopefully you can understand my ramble.....

Can you post something visible to explain your technique?

 

[soggysandwich]

basically, you put a hole in the return line near the water level, so once the water siphons to that point air enters the tube and the siphon is broke and it stops

 

[West1]

Right on. Thanks

 

[aquatic_wonders]

basically, you put a hole in the return line near the water level, so once the water siphons to that point air enters the tube and the siphon is broke and it stops

Can u just drill a hole on the pvc pipe that connects the spout or outlet pipe which is loctaed on the overflow box?

 

[Calmwaters]

any more opnions?

 

[fourty2]

if you are going to go with check valves,get bigger ones than that you need,you will also need reducers to attach the bigger check valves on your pipework....this will hopefully not reduce your GPH flow...but probably be a pain in the ass if you get some blockage...the first option i mentioned in my first post is probably the easiest one to do...and cheapest..
hope this helps,i went through all this with my tank

 

[Calmwaters]

Can u just drill a hole on the pvc pipe that connects the spout or outlet pipe which is located on the overflow box?

What about this idea what do you guys think?

 

[Danh]

Bigger check valves may just cause more head pressure and slow you down. I always locate my returns high in the tank, make sure my sump can handle some extra water but ALSO put at least two check valves in it too.

I don't get that last one...