Reservoir pressurized at idle,water disappearing through the bottom,blowing pipes and clamps failing to hold.

Just take the hose clamp of the bottom line of the pump and drain it out from the tank. Then remove the pressure line on the back of the pump with wrenches. You have to hold the big nut that's in the pump to loosen the line nut and take it off. Drain both lines while disconnected and you're good. All liquid is removed now and you reconnect the lines, refill the reservoir, start the engine and run for a minute, shut engine off then refill the reservoir. That's it. Done.

Dear Tim
Disconnect the heater hoses from the engine block.
Using some steel or plastic pipe of the right diameter to fit inside the hoses.
Clamp the pipes inside the hoses, and attach a garden hose or a compressed air hose to the pipe to blow the heater core clean. Remember, the normal pressure that the core is designed for is about 15 # per square inch, so either normal household water pressure or an air compressor can blow the core to pieces, so be REALLY gentle whilst blowing it out.
God bless your efforts.

turn the temperature up to the hot to blend the hotter temperature

Blows out? Probably a head gasket. they don't always blow white smoke. Parts store sell a kit to check exhaust in the reservoir or radiator. Best bet. If it blows out, Fill it with water, leave the cap off. Start it and put your hand over the reservoir opening. You feel any pressure being cold. Head gasket.

there is either a pocket of air or the car is burning the coolant if there is no leak. check inside the car for any coolant leaking under the dash if so the heater core has a hole in it.

try to flush radiator,sounds like it has sediment in bottom of it

I just finished replacing mine.

It is much easier if you do these steps:

1. Remove the serpentine belt.
2. Remove the nuts holding the main fuse box over the battery.
3. Remove the reinforcing bar over the battery.
4. Remove the battery.
5. Remove the windsheild washer tank.
6. Now you have access to remove the pump pulley. Without removing the stuff, it may be possible, but it will be extremely difficult.
7. Remove the pump pulley.
8. Loosen the high pressure hose fitting.
9. Remove the return line clamp.
10. Remove the power steering pump mounting bolts.
11. Remove the high pressure hose fitting.
12. Remove the power steering pump while sliding off the low pressure hose.
13. Remove the clips holding the reservoir on the pump.
14. Remove the reservoir.
15. Install new o-ring on the reservoir.
16. Install reservoir on new pump.
17. Install clips to hold reservoir on pump.
18. Install new o-ring on high pressure fitting.
19. Place new pump in position while sliding on low pressure hose.
20. Loosely attache high pressure fitting.
21. Tighten pump to mounts.
22. Tighten high pressure fitting.
23. Install clamp on low pressure hose.
24. Install power steering pulley.
25. Install washer reservoir.
26. Install battery.
27. Install reinforcing cross member.
28. Install fuse panel.
29. Install serpentine belt.
30. Bleed the power steering system.

Faulty coolant temperature sensor and a faulty heater control valve.

Sounds identical to a problem I had on my motor this year. The EGR or exaust gas recirculation cooler to give it, its full name had failed. Basically a little radiator sits on top of the exaust manifold and admits some exaust gas back into the engine. Its water cooled and they do split loosing coolant internally into the exaust. Good news is its an easy job to replace not so good news is they cost £220. To check yours you need to remove it and look into the pipe that feeds the inlet manifold, any sign of water there and its goosed. Hope this helps, Neil

Looks like the carry pipes are leaking. Inspect the pipes going out of the reservoir. They may be leaking. Run the water motor to see which pipe is faulty.