New pool owner/member need advice.

First house first pool etc.

Had a company come out and drain and pressure wash pool and epoxy paint ( forclosed house 3+yrs of algae ) They are coming to repair a diverter valve as well.

They said in there experience the inline chlorinator is useless and they recommend the floating dispenser since it delivers directly to where you swim. 2nd guy who is doing some electrical work said that they are the most useful things and floating thing is useless. So which one do I use ?

Also I have cartridge filters guy 1 said to rinse them off with water and to try them out since bands are still good.
Guy 2 said cartridge suck get sand filter and if you stay cartridge replace those due to algae.

Anyway can't I just use the shock treatment ( bought 50 in preparation for dealing with algae) put those cartridge filters in bathtub or giant trashcan throw a packet of shock treatment to clean off algae and let it soak? Filters look pretty good just dusty imo.

Whew! That's a lot!
First: Explaining all the "why"s is much easier if you can do some reading on our sister site, poolsolutions.com

All professional pool installers and repair guys have their own preferences, usually based on what they know.

Inline vs floater: Both ASSUME you will be chlorinating solely with 3" Tri-Chlor tablets If you learn our B-B-B system you'll find out the tabs can be great, or seriously problematic. They add stabilizer and are VERY acidic. Personally, I stick to Chlorine Bleach or its stronger form, Liquid Chlorine. It's cheaper than tablets and more controllable. When I use the Tri-chlor tabs, I use a floater--they are about $10 versus far, FAR more for inline chlorinators and don't need to be installed. I also use a Salt Water Chlorine Generator so my call use tri-chlor at all is very rare. But the nonsense that floaters don't work is....NONSENSE! He just wants to sell you an inline + installation.

EVERY type of filter if sized and maintained correctly can give fine results. The second guy (again) is trying to sell you a sand filter + installation. If the cartridges are good, then just use that. (Personal bias--I have a sand filter and wouldn't buy anything else---but if my pool came with a cartridge filter in good shape, I'd use that).

I don't know what your "shock" treatment is. It could be all kinds of things, but mostly they are either Di-Chlor powder or Cal-Hypo powder. Either, dissolved in water should kill the algae in the filter cartridges. But so should hosing them down. Personally, again, I'd use bleach or Liquid Chlorine.

Sounds like the first guy is trying to save you money and the second is trying to separate you from it!

. . . membership updated.

Cartridge cleaning sticky, here: http://www.poolforum.com/pf2/showthread.php?18044