Bought a 06 Skeeter ZX225 last year. It has a Lowrance HDS8 Gen1 on the console and a Lowrance X135 on the bow. The bow unit screen has a huge black dot that is getting bigger each trip. Any recommendations that I should update the bow unit inexpensivly to? Or should I save up for a complete new systems?

Boat is mainly used for Jr High fishing tournaments. We�d like to increase our knowledge and or tournament success but do not have an unlimited budget. TIA.