Heat cable but no heat

[cornsnakekeepr]

hi guys, if anyone can help me it will be greatly appreciated. I have finished my rack and had installed 22W 6.8m heat cable that i had bought from a local pet shop, it is a Komodo (Akwa) product. i installed it with 5cm gaps and it goes 4 times under each tub, and i also have it sandwiched between aluminium foil tape. i know that i have connected it correctly as i can feel what i can only describe as a change in temperature it is not getting no where near the desired temperature. the other thing that is a little irritating is that parts of the cable havent heated up at all.
so please can anyone tell me what have i done wrong, what can i do to fix it? is it the make of cable or did i just buy duds?
if anyone recommends another brand please let me know what and where i could possibly get it in PMB area
also as my tubs have a foot piece i have put a tile on top of the cable but that doesnt seem to be helping. i also bought a thermostat for it but havent connected it as the instructions were greek to both me and my mechanic father and whats the point considering the cable isnt getting warm enough to warm me!
i really need to get the heating running asap as i went a little crazy at my first expo yesterday and bought 4 snakes, 3 corn hatchlings and a young female ball (my first ball )
anyway sorry for the rant, if anyone can help me with my little problem it would be greatly appreciated.
thanks

[Kakibos]

I always buy the 20w and 30w cables(yellow and orange cables) they are also about 4m, and they work 100%. I have found in the past the long cables(blue ones and green ones) just do not get warm enough, maybe its the length I am not sure.

[cornsnakekeepr]

thank you i will definitely look out for it. at the moment after speaking to an electrician frien of my fathers who came to explain the thermostat, i have removed the cable and have replaced it so it is alot closer together so it essentially looks like a keating pad, so far it has heated up faster but i am unsure if it will reach 32 degrees but this is a test. if it doesnt i will go look for the other coloured cable
thanks again