Potamogeton Gayii - id

wow, it's hard to tell from that big plant mass

it may be a Najas species. Najas grows out quickly by branching. P. gayii spreads by runners through the substrate. Try to pull out a single plant, if you start pulling up more plants with runners, more likely it's P. gayii. If not I would guess Najas guadalupensis....

Thanks hooha, yeah that picture sucks. Whatever this stuff is, it's driving me nuts. Funny it seems to do both, but I would say it spreads by more branching. The plant is very tender and breaks off easy when pruning, so it goes everywhere.

Although it's nice looking for a while, it's hard to control.

After looking at a picture of Najas guadalupensis. I think Najas is the culprit. This is the gift that keeps on giving - CRAZY WEED... Don't plant it with CO2 injection unless you really want it bad.

lol, yep with that explosive type of growth it sounds like Najas....