bubbling

I just finished plumbing my tank and it only has one hole drilled in the overflow. So i decided to plumb it using a durso standpipe. I even got a cap and drilled a hole in it and pht some airline tubing in the hole with a ball valve. As soon as i started running the tank with water i noticed...

What could be happening to these Rasta Zoas they have been ballooning and with very strange behavior after being only 14 days directly high on the tank under the AI PRIME HD. They bubble up Their ring colors fuse It happens in the afternoon when sunset lights are high on RED Please help, this...