Sump plumbing. Feedback?

Here's a simple diagram of how I plan to plumb the sump on my new 105. I'm new to plumbing sumps... Heck, I've never plumbed anything in my life!
Everything is flex pvc with standard bulkheads and fittings. Could you critique before I start to cut and glue? Thank you, Helen

 

Two comments.
First, I hate slip bulkheads since you end up cutting them apart in the future and they are wasted. I would always recommend thread x thread bulkheads and do so in my Bulkhead Installation Tips sticky post found on many of the reef forums including this one:

http://www.3reef.com/forums/new-hobby/bulkhead-installation-tips-111422.html

Second, on your return pump, install a ball valve on the discharge side of the pump to throttle the flow if needed then use 1" PVC or tubing from the valve up to the tee for the least amount of headloss or resistance to flow then use 3/4" from that point on with a valve on each return so you can balance them as you have indicated.

Well three comments, I just thought of another.
Never, ever, I repeat never install valves in the overflow unless you are using the new Bean Animal or similar standpipe which uses one standpipe normally with a backup. I prefer to keep my overflows simple, the KISS method, so use a single overflow with a Stockman standpipe in 1". The tank is a 100G with a 30G sump using a WaterBlaster HY-5000 and has been trouble free for 10 years last month.

 

Good advice, thank you.

If I'm understanding correctly, I should put another 3/4 ball valve above the pump to adjust flow, and use the top ball valves to balance the flow.

A question about the ball valves on the drains: I've just put them in the plans in case I have some sort of leak or plumbing modifications to make. Then I can shut the water off before the entire overflow drains on to the floor. Are the ball valves ok to use in this way; not to throttle the drain back but to provide a redundant safety shut-off: or are they inherently evil.

 

If you T the two overflows into each other, consider Going to 1 1/4" to 1 1/2" at that point.

 

Assuming you have a corner drilled tank or something like that. Just make sure you have enough room in your sump to allow for any drain issues. Ball valves attached to the drain spells disaster for me. My though is your DT overflowing as a result.

 

I'm convinced. No ball valves on the drains!

 

Let the more advanced reefers chime in as well. Those were just my thoughts as I was setting mine up.

 

Correct- valves on the drain are unnecessary. In the event of any disaster, the overflow will prevent flooding from the drain side.

 

The overflow will only drain down to the top of your standpipes and will break suction at that point and quit. In my case that is 3/4" from the normal operating level or about 3.4 gallons of water in my 60" long 100G display. The sump is a 30G and operates about 2/3 full so has plenty of freeboard or excess room to store the extra 3.4 gallons when the power goes off.

Depending on the size of your return pump, as I mentioned before I would increase the discharge size to 1", at least one size over the pumps connection, to decrease the head so flows stay higher. Then at the last possible moment or at the tee to each outlet drop it to 3/4". Almost all pump manufacturers recommend jumping up one size in the plumbing to help flows since larger pipe has a lower friction loss due to lower velocity in the line.

 

Now here's another dumb question. Based on the diagram above, can I put the skimmer in chamber one and the drains in chamber 2? I can jam both the sock and the skimmer in #1' but it's dumb to have to struggle to remove the socks, also the drains have to curve to get there. The drains in chamber 2 will allow a straight drop and make the plumbing cleaner. The other advantage, space wise, of switching the skimmer and drain is the second compartment has "ribs" on the floor (have no idea why) so the skimmer will not sit flat without modification.