My Hot Water Heater Is Losing Its Pressure But The Cold Has A Lot Of Pressure, Can You Help?

Electrolysis is probably not the problem. Sediment in the tank from very hard water,the shut off valves near the faucets may be clogged with calcium deposits or it could be as extreme as clogged pipes throughout the house.  Sounds like it is time to call a plumber.

Could be that electrolysis has caused the inside of your pipes to close up. You can tell if this is occurring by looking where the water pipes come in and out of the water heater. If it looks like a lot of corrosion the this could be the problem. Make sure all the shut offs are wide open. Might be time for a new water heater.

Hot water has little pressure cold has lots need help

1. You first need to look under your sink(s) in bathroom and kitchen,
   adjust the valves by turning to get more or reduced pressure. 
2. Remove by unscrewing the round part directly where the water exits on the faucet arm. Clean the screen with old toothbrush. Very common that small amount of rocks and sand have accumulated from rusty pipes and dirty water heater. 
   
3. There
   is a clogging in either the water tank outlet line (left side ON the
   tank) by maybe too much rust or calcium buildup in the water tank or
   pipes (left side). This clogging of course can also lead into your pipes
   going to the faucets and shower.