Hi, i have a Juwel Trigon 190 and want to change one of the light tubes. I want a 'marine blue', but i dont know what type i need?? It says on the light tubes i already have 'Juwel 28w' but looking on the net, all i can find is 24w & 30w. I dont even know if its a t8 tube or t5 ?? is there even...