double check math please

[irvinenewbie]

I will be using Tri-chlor 1 inch tabs while on vacation for 10 days. I've never had any experience with tri-chlor. I got an Aqua chem floater which contains 4 lbs of 1" trichlor tabs.
http://www.aquachem.com/mp/v/index.jsp? ... mt=default

I need to raise FC by 10ppm, lower pH by 0.5 to be within range upon return.

Per pool calculator, 2 lb of trichlor is needed to raise FC by 10. I have a 4lb floater. Can I open it and take out half of the tabs? The instruction on the bottle says to not to open and refill it. But the lid opens easily and can be emptied or refilled.

2 lb of trichlor will lower pH by 0.56 for my pool. So am I done once I put in trichlor? Do I need additional MA to lower pH? I don't know if the calculator already took into consideration of trichlor's effects on pH once I put it in as the chlorine source.

I have a 21K gal pool. Someone mentioned that since 1 inch tabs dissolve quickly, I should puncture the hole that is for a 15K pool, not 20K pool on the side of the floater. Is this correct?

Any other advice or mechanics regarding the use of floater? I've never used it before.

Thank you.

 

[frustratedpoolmom]

I don't see the need to take out any of the tabs. Just leave the floater in the pool until the tablets are completely dissolved. The tablets will slowly lower the PH over time. Just test the ph when you return and adjust further with acid if you need to (assuming the tablets are gone.)

 

[irvinenewbie]

I actually want to save what's not needed for another vacation. Besides, don't want to raise CYA too much with trichlor.