I don't know what you mean about finding "a small opening with little viability to solve the issue." What are you looking at?

In any case, since this only affects the bathtub, it probably means that something came loose and plugged the line at the bathtub faucet. If you are somewhat handy, dissassemble the faucet to get at the washer or cartridge. If this sounds like Greek to you, it might be simplest to just call a plumber.

I also think something came loose and clogged the hot water line at the faucet.

I second the suggestion to turn off the water, then disassemble the faucet and you will probably find a big chunk of lime in the hot water opening.

You may also have a clogged anti-scald valve if it's newer.

You might try flushing it backwards first before taking it apart:

1. turn off cold water supply to hot water heater. If the heater is electric, turn off the breaker too.

2. Open a hot water faucet - such as a laundry tub - or the Pressure relief valve on the water heater. Don't use a kitchen or bathroom faucet for this.

3. Place a wet rag over the tub spout and hold it in place

4. Open the hot water on the tub

5. open the cold water on the tub

Water should run through the hot water side backwards and flush the crud out of the faucet.

6. Turn off the tub, close the hot water faucet that you opened in step #2, turn on the cold water to heater.

7. Open the hot water tap to see if it works. Purge any air out, then turn on the breaker to the water heater.

Your suggestions were helpful, good news we got slow flow in hot water in bathtub, but the bad news the others faucets are now slower which leads us to believe there is something blocking the pipes. Next step, drain the hot water heater, replace the heat element and clean out the sentiments as this may be what are breaking up and clogging the pipes.

Again thanks for your help, any other suggestions! This forum has been awesome...go GW!