Crash out of nowhere!!!

[IronRising]

So i had a huge crash on Thursday. Thank goodness for ammo lock i'm pretty sure it saved my fish. I'm hoping to get some input from you guys on this situation.

First i guess ill explain from the beginning so you guys get the whole picture. I was running a 45 gallon with 90 gallon rated filter and transferred everything (ie live rock, filter, substrate, fish, corals,) from the 45 to my recently set up 90 gallon. I put new clean substrate ( crushed Aragonite 1-2mm) on the bottom of the tank and the already cycled stuff on top. added the filter from previous set up, as well as a new 90 gallon filter. added the 70 pounds of live rock as well as another 30 pounds that i had cured.

I waited a couple of days did some tests before adding the fish and corals in, everything was looking perfect!!! i had a very small ammo spike after adding the fish .25 for about 2 days then nothing , no nitrites , low nitrates.

A couple of days later woke up in the morning had my coffee, decided to run some tests to double check the tank. Good thing i did because the ammo was at 5 and climbed to 7 before i got the fish out! i dosed ammo lock to keep the fish good while i got everything i needed to get a holding tank.

I re-set up my 45 as the holding tank, got the fish out, corals are over at lionfaceman house. All live rock is back out in a curing bin, and substrate has been pulled out of the tank cleaned vigorously and put back in the tank with brand new water. all filter media has been replaced.

I tested my water again to day in the 90 with nothing except water and substrate, and its back up to 5 for the ammo. so im assuming its the substrate. I spent 4 hours washing it out. any thought, idea, fixes?

Thanks crew,

Scott