Based on the pool where you mine solo I never heard of that pool before and according to Whois, it's 2 months old.
It's bitaxe pool, they have active topics all around even local boards, I would also be normally suspicious about it but in this case I doubt they would have done this to advertise their pool like this, the owner has already
an account here Besides, it's a pool for low hash miners like nerdminer or bitaxe or other usb stuff, not built to attract ASICs, my opinion, a hobby pool for testing toys.
As for OP problem, if you're not doing this for learning and testing and you actually want to solve a block and get it accepted in time, then I would advise to mine over a solo pool.
Was just about to post the same thing.
Going to also say that if you did follow one of the guides to setup a solo testnet pool like this:
https://bitcointalk.org/index.php?topic=5415335.0I could see someone thinking that it would work for an external stand alone ASIC.
Then you google some things and public pool does come up.
Either way, my original comment still stands, don't do it yourself.
-Dave