Question about DIY overflow to sump

[Kristen87]

Hi everyone!

Just joined up today to ask this question, hope that's ok. Been struggling with getting my head around how to make a foolproof overflow to a sump (my brain isn't functioning properly - I have a 9 week old baby so I blame baby-brain!). I think I'm nearly done... but here's my question.

I have built 2 PVC overflows just in case one gets blocked by plant debris (you caught me - its for a freshwater tank). One overflow has quite specific measurements, but one ended up needing a bit of hacking and re-gluing and as a result one of the "bottom loops" is ever so slightly lower than the other (see picture to see what I mean, one of the loops can fit a pen under it when held flat). My question is - will this affect the ability of my overflow to restart on its own if the pump is turned off and on again? i.e. will the difference in water level allow the water to drain out of the middle section, meaning I would need to re-prime the overflow every time the pump has been off? Or will water stay in the middle section so the water will start overflowing into the sump again once the pump comes back on? Sorry I know this should be common sense, water flows to the lowest point possible but my brain is just refusing to cooperate with me!

Also is there a way besides having a backup overflow to safeguard against flooding my tank/running my sump dry if my primary overflow is blocked? I like strong flow/filtration so needed 1.5 inch pipes to accomodate the flow, it would be a lot easier to hide the pipes if I only had 1 overflow instead of 2!

p.s. I know I still need to drill my check-valve in the top loop to prime the overflow.

 

[fishgate]

Why that loop in the plumbing? That is not the typical way to do overflow plumbing.

As far as your siphon question, that pipe will remain with water up to the top bend (middle) providing the filter screen on the left is the intake (water level will be wherever your tank level settles at when the pump stops). The right side of that will drain down to the lower sanitary tee providing the part that disappears to the top is a standpipe.

 

[RocketEngineer]

Will it work? Probably. But these PVC overflows don't work WELL. Being 1.5" I'm guessing it will be hard to start initially and keeping the air out of the siphon tube may be a challenge. They really don't work as advertised. A HoB overflow would probably work better in the long run.

Good Luck.

 

[zachts]

Personally I'd have just gone with a ready made HOB overflow, but if using these I'd use an aqualifter pump in place of the checkvalves to maintain prime and remove trapped air. I wouldn't count on getting more than 300gph from each and that might be pushing it a little. What flow rate are you shooting for? two of these may not cut it.

Dending on how you have things setup, auto top off or not, a couple float sensors and a relay could be used to shut down the return should the sump run low or the display tank gets over filled.