Theoretically it should stop all siphoning

it will temporarily , but theres not enough pressure in a gravity feed to stop it completely so if enough time goes by it will slowly leak , it will stop the skimmer from overflowing though :)

As long as it does that job, I can always control the power from the Apex. I'd only turn it off during coral feeding anyway.

Would drilling a hole on the return loc-line be another (additional) option to help with controlling back-siphon? I did that in my previous tank but it was above the water line, so the constant water spray was annoying.

Brian,

Whether you do it or someone else plumbs your tank, remember to dry fit everything so you know for sure everything is going to fit before you glue. I glue everything that is under pressure, but I only silicone those pipes that are under gravity flow. I imagine most people glue everything.

Also, most of the time, leaks will be from the bulkhead so be extra careful there. Hand tighten & only add a 1/4 turn with a wrench. Any more and you risk damaging the glass around the hole.

Mine is an external overflow box so my ball valve for the return is under the overflow for ease of access, as opposed to being right near the pump outlet. Of course, part of the reason is also I don't T-off my return to run any media reactors (I just use Maxijet 1200s for that). I use a controllable flow DC pump as well, so I'd rather run my pump at lower flow and hopefully put less wear and tear on my return pump and just use easily replaceable MJ1200s for the media reactors.

Anthony

absolutely , a syphon break is def one way to stop it , placing your lines near the top or using locline to angle them is another option as well. check valves will buy you enough time to stop your skimmer from going haywire or even two check valves in line:)

My above recommendations are to help keep the plumbing simple for you as possible since it's your first go. The advantage of a manifold is to run reactors or other equipment such as biopellets or GFO reactors without needing extra pumps to run those items. The manifold is simple...it's just a few Tees added together. Reduce the Tees to 1/2", add a ball valve to each manifold output. I could find a pic probably later...

For the purpose of helping the skimmer to not overflow, yes. Do not rely on it to keep your floors dry though. The less feet of plumbing you have and tall standpipes you should not have a lot of back siphoning anyway. Make sure there is room in your sump for the back siphoning as well as the full volume of the overflow (just in case). You can set your Apex to turn off the skimmer when you turn off pumps for feeding too. You can also turn off various pumps (like the return pump) with the push of a button on an Apex. You can also hook up powerbars with switches if you didn't have an Apex, so there are lots of options rather than unplugging the return pump.

plumbing
 

I have put aside my tank upgrade project due to lack of knowledge of plumbing. An drilled empty tank has been stored in my garage for a few months now. I am glad to get useful information from the forum. Hopefully my upgrade project will eventually be resumed.

Good idea about dry fitting to check. I'll definitely put that on the to-do list when the time comes. I'm still unsure whether to run reactors through the return pump. I think I'll ditch the Biopellets and go with vinegar dosing, and just run a TLF for PO4 removal with RowaPhos or something.

That's a great idea. I'll grab a loc-line for the return and angle it up/have it high up the water line to reduce the back-siphon. Probably will still get one check valve just to help with the skimmer.

Yes, I will have my Apex to do these things. I want a one-button macro so I/wife can feed or do maintenance/WC with things turned off temporarily without having to unplug stuff or switch off the power bar. Thank God for controllers! :mrgreen:

Fwiw, my last two tanks have been plumbed in such a fashion that the back siphon doesn't affect the skimmer. The skimmer chamber has a 4" higher water level than the return chamber so the return chamber takes all the back siphon. My skimmer stays running during water changes.

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Curious, does anyone use vinyl instead of PVC for plumbing here?