I am performing the spring start-up myself for the first time and checked the level in my sand filter, assuming that the pool company had never topped it off. I have a Pentair triton TR-140 and the installation and maintenance brochure is at the link that follows:

http://www.recsupply.com/Documents%5...I%20Manual.pdf

According to the brochure the headspace between the sand level and the top should be 13 ½ inches and in mine it is now 23 ½. I clearly need to add some sand.

No. 25 standard silica is recommended (uniformity coefficient not greater than 1.75) 0.18-0.2 inch diameter particle size.

I have 2 questions;

1. Would anyone like to estimate how many lbs of sand I need to buy? Since the total in a fully filled filter is approx 650Lb there is considerable room for error! Iplan to buy 2-3 large bags and see how far that takes me, but would rather avoid sveral trips.
2. What sort of sand is #25. Will it be a big problem if I add just regular sand? Would 'play' sand be any better?

Thanks