The pumps will be controlled by a power strip with relays built in...Figured I would ask, I'm going to open up a standard power strip and see how they wire the indicator lights in those.
Generally as cheaply as possible; most power-strips simple have a neon lamp attached to tell when it is on, wired nearly directly with the power from the wall. But you say your strip isn't like that, and has relays to turn sockets on/off (sounds kinda cool - got a link?).
If so, and you seem to not mind opening it up, what I would do is look for the LED, and likely it will be connected between a ground and a resistor; note the size of this resistor (it may be all SMD - if so, hopefully its not so tiny as to not have numbers on it - ie, "103" would indicate 1K ohm). With that in mind, get another LED and a length of two conductor wire (phone cable will work), and hook one wire to the -other- side of the resistor, then to another resistor of the same size, then the LED, and to the other conductor, and the other conductors end would go to ground.
Basically, you are making an LED extension cable in parallel with the existing LED/resistor combo; you don't want to just wire up the LED to the resistor in parallel, because that might over-tax the resistor (which is likely a very low wattage device), causing it to burn out. Generally, whatever is powering the LED (without a schematics, hard to say) - is likely a transistor or mosfet, or some other kind of buffer output (or a microcontroller with pins that can source/sink enough current - if it is wired directly to a microcontroller, you might want to look up the spec on the controller to find out how much current its pins -can- source/sink) that can handle the extra very small load (you might want to run the numbers thru an LED/resistor calc online to make sure you are using the minimum, so as not to overtax anything).
The extension cable shouldn't be very long; you could probably get away with a few feet - but if you are concerned, you could drop the resistance of the LED and figure out the wire resistance to add it back in to make up the difference (there are online refs for this as well).
Finally, make sure your connections inside the power strip are -very- secure; you may want to blob some hot glue or silicone on top of them - so that they don't come loose and short with the house current output from the relays. Use grommets with strain-reliefing, or add jacks to plug in the extensions if you want (and can - if there is room).
Hope this helps and is understandable...good luck!