My Hayward sand filter is throwing sand back into the pool. I already took it about and don't see any cracks. What's else could it be? I have 4 days until I am no longer able to return it.

SOURCE: How to change sand in Hayward S-200 Sand filter

hayward S-180 filter takes 150lbs, S-210 takes 200lbs not familur with the S-200. To change sand you have to remove the vari flow valve on top. You can either unplumb the filter and roll it over on its side and try washing the sand out or try scooping it out upright. Whatever you do dont damage the laterals on the bottom of the filter. When refilling with sand you want to make sure all the laterals are undamaged and in the down position. I always fill the filter half full of water to keep the sand from damaging the laterals while re-filling the filter with sand. Make sure you use pool filter sand and not play sand!

SOURCE: Sand is coming out of our Hayward filter and into

One of the lateral fingers on the inside was cracked. Once we replaced this with a new one the problem ws solved.

SOURCE: no suction from hayward variflow pro series sand filter

Try these tips. I am guessing that one of these is the reason that your pool filter is not working properly. If you try these suggestions and they don't work, let me know and I will trouble shoot with you again.
1. Check skimmer and pump strainer baskets for debris.
2. Check for restrictions in intake and discharge lines.
3. Check for air leak in intake line (indicated by bubbles returning to pool.
4. Backwash your filter.
5. Be sure Vari-Flo valve is set on “Filter” position.

SOURCE: hooking up filter to pump and pool

This website contains a copy of the owners manual for the S180T pool filter. It should have all of the information that you need.

http://www.backyardcitypools.com/images/hayward/pro-series-manual.pdf

It is in PDF format. let me know if you have any trouble opening it.

SOURCE: I have a hayward SP714

Sand filters have a screen at the bottom. This screen keeps the sand from getting out because it has slits or holes that are smaller than the size of the sand grain. The slits are large enough for the water to pass. If the material breaks there are areas that are large enough to allow the sand to pass and this won't stop until you replace the strainer elements.
In order to do this, you must remove the sand, remove and inspect the strainer and replace the sand.
Bring your model to a local pool supplier, confirm what I am saying, make sure they have the necessary parts and go from there.
Gary