Hut Tub Drain Cover

I have a cheaper Chinese Hot tub and have an issue where the drain level is too low so when 4 people sit in the tub, water drains out and the next time 1 or 2 people sit in the tub it is too shallow. not to mention all the extra water and heating needed to replace the lost water.

I have designed this drain to raise the drains water level my about 1" which will resolve this issue.

i thought i would share if anyone else has this specific issue. the drain cap that this clips onto is 81.252m