Reservoir
First lets look at the pump and reservoir that Thermaltake has provided with the Big Water 745. The P400 is an in-line pump and from the specifications we see the pump is rated for 400 L/hr, which is roughly 106 G/hr. This far more than the previous Big water at 90 L/hr and slightly more than the average kit. Thermaltake doesn't mention the PSI output. The P400 provides 2.10 m of lift using 10.8 Watts of power.
Above we have the P400 connected to the reservoir or as Thermaltake calls it the liquid tank. The liquid tank is a little taller than I would have liked it to be, standing at 110 mm it may be a little cramped in some cases. But holding 350 cc of coolant it more than doubles the amount of coolant compared to the previous Big Water. Also on both sides of the liquid tank we have high and low water marks.
Here we can see the how the P400 mounts to the liquid tank. The intake fitting of the P400 fits like a glove with the liquid tank. Thermaltake has fitted the liquid tank with dual o-rings to prevent leaks. The liquid tank is made of a hard plastic tinted a dark color.
The top of the liquid tank is where we have the quick connect and the see through cap for refilling. The quick connect is for return water flow and the liquid tank with the cap on top makes for easy filling or refilling. This is a big improvement from the earlier Big Water and easier than most kits. Both the P400 and liquid tank have rubber pads on the bottom.