It doesn't matter the height of the tangki when you have a pump. It all depends on the force of the pump. Normally a pump would work for a shower. Alternatively you can buy a heater comes with a pump.

It is a good buy. Just make sure you have the right power point for it and not shared.

It is ok sharing with a light which consume little power. 2 feet type is 20 watt and plus its ballast maybe takes another 20 watts. Total not more than 40 watts compare to 3kw a power point can support.

Water pressure will not good when coming from the tank. Unless your tank are locate higher.

Need to use good quality valve, never use PVC valve.

Kitkat,

Click the image for more explanation.

[attachmentid=3684506]

Great to hear that. you are most welcome

By the way, if your piping is exactly what I suggested, ie from tank and from direct with non-return valve; from your description, when you on the pump the pump is pulling water both from tanki and direct. The reason I am saying this is because it is good to use the tank water, otherwise the tank water become stale or become dead water. Since water is also drawn from tanki it is constantly being replenished from direct which contain chlorine and it "clean" the tank or sanitized the tank killing micro organism or germs.