Replacing broken main drain cover

[kelemvor]

Sooo.. I jumped in my pool yesterday and landed footfirst on top of one of the main drains.. foot went straight through the drain cover. I stopped by the pool store to see if they had a replacement and they told me the type I have is now illegal and I would probably have to get some universal. They didn't even have one in stock and couldn't find one in their catalogs they thought would fit.

The drain cover is a cantar, there are two screw holes that are exactly 6.5" apart from the center of each hole. The diameter of the whole cover is exactly 7".

I can find the exact covers for sale on the net, but if they're illegal then I'd rather do the right thing if I can. I really don't want to drain to do it, and I doubt I can hold my breath long enough to get it done. Is there a trick to replacing a main drain cover? Poolstore suggested their pool service guy would do it with some scuba gear.

So, my questions are:

1. Where can I find an appropriate replacement drain cover?
2. How should I go about replacing the thing?