Dual pumps... Should I?

Here's my current setup:
Sicce Nova submersible aquarium pump, does 200-800 liters per hour. It's submersed in an open 25 liter reservoir from where the water goes to the block & back.

I'm ordering a regular BlackIce radiator, since that's the best radiator I've seen for sale in any Finnish online stores. Also, I can fit it perfectly to the bottom of my case, Antec 1030. It'll be fed air by an old aluminum chassis Panaflo 120mm, most likely at 12V.

I'm going to get an airtight reservoir that I can fit inside my case. Now, since my original pump isn't exactly a beast, I'm considering ordering a second Sicce Nova. It's cheap and I already have one.

What I need to know, is that should I get a second pump, what are the downsides & upsides of it and how to hook it up in the loop.

I've thought of 2 ways to hook it up sofar:
1. Reservoir->pump->rad->block->pump
2. Reservoir->paraller pumps->rad->block
Possibly put radiator after the block?

Thanks for reading all that Help very much appreciated

Water cooling should go res-pump-block-rad then back to the res. That way the warm water from the block will be cooled back down. I would go with one pump myself.

I can see 2 good things in having 2 pumps

1. if one dies you have a backup
2. you will have same gph but it will be a stronger gph if you put lots of water block in the future

down side is that its harder to setup (of course) and you have two remember to turn on a nother whole pump

I would just get a nice ~300gph pump and stick with one

Ive found best results going pump->radiator->block->reservoir->pump

Definitely use two pumps if you can manage it. a 25L reservoir? yeah, i'd use a dedicated pump to bring the water from the reservoir(assuming it's not in the case, unless you have a Dell ProServer 2000 case in your home!) and have it pump to a case reservoir, then use another pump to pump from there to the block(s) and then radiator, then back to the orig reservoir. should work great. I've got a 5 gallon bong system going and i use a 400gph pump to supply to my mini reservoir inside the case with a submerged 140gph pump that pushes the water through the blocks then into a small (5x7) radiator, then back out to the top of the bong to sprinkle. Works great,I also use a dedicated cooling pump inside the bong, to keep water circulating to the top of the bong and cooling it. Without the extra pump, my flow rate was mega slow since the pump inside the case had to work overtime just to pull a large column of water from the bong to the system. and then there's the added security of a backup pump should one fail.

I wish I could fit that 25 liter reservoir in my case, it's got a huge heat capacity I'll propably get a watertight 1 or 2 liter reservoir to put the pump(s) in, that should fit in the case.

I would change to another pump, but it'd become more expensive than I can afford at the moment. Sicce Nova is ~$24 and a good Eheim is ~$92... A bit on the high side, both pumps, IMO.

The reason I originally thought to put the rad before the block is because I'm using a submersible pump, which adds about 10W (not much, though) of heat to the water. If I go with 2 pumps, that's 20W, a noticeably bigger amount. The rad would cool the water before it enters the block, getting rid of some of the heat put out by the pump.