Very high po4 will be a non issue. The next thing to wait on is dinos which will likely come, they will seriously tick off the nems and will likely be the hardest part of this process. I recommend you have a plan in place to deal with them, one that does not include a microscope. Be ready to dose po4, nitrate, and have funds for a UV if you need one.**UPDATE**. So far so good. Never got any ammonia. Nems look like they're doing great. Acclimating for 2 weeks with lights ramping up from 50%. Nitrates around 5, but PO4 is off the chart (literally - blue tint on hanna phosphorus checker and 200 flashing). I wanted to add my clowns this week, but am going to hold off until I feel they'll be safe.
@Eagle_Steve or anyone else......
Would VERY high PO4 be an issue for the Nems or fish? Will my water changes bring the PO4 to correct levels eventually or should I add some gfo? I hate gfo.....but would hate to lose any of the Nems.
Dinos have consistently been the only thing that has come close to killing my nems in new tanks.
Clowns should be perfectly fine to add fwiw