29G Sump Design

Sump looks good, although the 12" tall baffles may be a tad too tall. Your not going to fill the sump completely with water, only about 2/3 full. It may work fine, but its close. I setup a 29G sump for my neighbors 75G tank and it works great. Return pump, he went with a Mag7 at first, then recently upgraded to a Mag18. He has a built in overflow that could handle it though.

Mag pumps have a reputation for being hotter than other pumps. I would look at Eheim myself. They seem like a better option. I am running the Mag7 on my 29G tank now and its great for my tank but I haven't had to deal with summer temps yet so the jury is still out on the heat issue. I didn't have to pay for the pump though, my neighbor gave it to me when he upgraded. I would have gone with the Eheim if I had to buy one. 2 pumps should NOT create any excessive heat.. it will just make your heater not have to work as much.

Looks basically like what I have planned for my sump, except I'm using a 30 long tank. I am going with a Ocean Runner 3500 for a return pump...I have an Eheim 1250 right now and it is a great pump (it is at least 12 years old) but I want a little more flow through the sump.
Out of curiosity, why are you going to run two pumps?
Robbie

On your DSB, I would go at least 6".

I think he is talking about the skimmer pump + return pump, right?

On the return, the Eheim will be the most reliable AND you can always throttle it down a little if necessary. Why are you underpowering the AquaC EV 120? It really needs a mag 5, minimum--a mag 7 gives even better results. Same for EV 180-- mag 7 minimum, mag 9.5 preferred.

um...ok.

You can skip the last divider next to the return pump, little purpose it has.

You should be fine with the skimmer outlet in the same side, as the bulk flow thru the sump is much larger than the amount going thru the skimmer. Yes, you will cause some amount of inefficiency as some of the "skimmed" water will get re-skimmed. No big deal. You could add a hose to the outlet and run it down to the bottom near the partition to 'guide' more of it out of the the skimmer partition.

As for pumps.. For in-sump ones realize that every watt they draw will go towards water heating. EVERY watt. If you use external pumps call it 80% of the watts will go towards heating.

This means your tank temp will rise according to whether your heater cycles during the day or not. If your heater(s) are ON ever during a normal day then they will be ON less by the wattage of heat being added by the pumps. If your heaters are not ever on during the day then you will have a temp rise. How much? Very hard to say. It is a function of the relative humidity in the room, the surface agitation, tank volume, room temperature, tank surface area, and your choice of tank temperature.

The most serious issue is if the room temperature ever gets near the temperature you run in the tank, like on a hot summer day. That's when those few watts will hurt.

Heh, I know my AquaCs. I had an EV 180 for about 5 years.