Welcome to our forum.
As far as MPS is concerned, you really don't need it at all. Dichlor is more effective by far both initially and for weekly shock.
I've always been told to never use ammonia based products(i.e. Windex) on acrylic shells.
Bill is correct about not needing MPS....but if you want to shock and be able to re-enter the water without having to wait for chlorine levels to drop, as you would with dichlor, then MPS is an excellent alternative. Entering the water between 30 minutes to an hour after shocking is a major advantage over dichlor shock. One other advantage I've found.....if your pH is high and needs adjusting down, unbuffered MPS will shock and help lower pH....unbuffered MPS pH is between 3-4. The biggest drawback to MPS use is its contribution to total dissolved solids (TDS) which is much greater than using dichlor. I prefer to use either MPS or dichlor depending on the situation as outlined in the parameters stated above. Correct......you don't need MPS but you may prefer it at times over dichlor.As for your initial fill, I see no need to shock a freshly filled tub. Shocking oxidizes chloramines and you should have no chloramines with fresh fill. I simply add 2-3 tsp. of dichlor after the fill, run all pumps for 10 min. or so and jump right in after the temp settles in....good to go.
Ok...thats the kind of infor I was looking for. Thanks windsurfdog. I appreciate your help. Thanks to others who have posted as well. Also Windsurfdog what do you suggest to use to clean the shell once the water has been drained...or is there a need to clean and polish it? Thanks again
I've always been told Windex is fine but never use alcohol based products on the shell.