Phosphate Question......

[Timbits]

When i first started my reef aquarium, i had a serious outbreak of every algae possible especially grape caulerpa, bryopsis, and dinos. i wasn't running any phosphate remover at the time, tested my phosphate and it was at 5!!! yes 5. i quickly grabbed some phosguard and have been using it till this day. Fast forward months later and i have no algae in sight so its been working great for me. Haven't tested my phosphate for a while but i know it is a lot lower but i dont think its at 0.

used up the last of my phosguard and i found that i need to change it pretty often so im thinking of trying Rowaphos as being more cost effective and better quality i think.

my questions is...

1. im worried that if i switch to rowaphos, i hear it can rapidly decrease phosphate too fast and can bleach/kill corals.
should i just stick with phosguard? i have no algae in the tank and sps is growing like crazy.

2. i plan to put the rowaphos in a media bag to keep it simple. on the website it says Don't rinse it, the water may cloud for a bit but will disappear and nothing will be affected.
should i still rinse it? seems like the water will turn black doesnt sound too good.

3. should i start with less than the recommended amount? i would say i have roughly 40 gallons, how much should i start with?

Thanks for all the help guys! pretty new with the phosphate stuff......