UPDATE:
last thursday, wa smy fill day, would fill third third third.
but upon filling, corner on the right was leaking ever so slowly.
had to empty and patch up.
patched both sides on the front so looks uniform and also creats a thicker boirder on the vertical side.
fast forward, filled up completely, everything is running now. 16c starting temp, 21.5c as of this morning.
first few fish intro is thursday.
when i was filling it up, i was having i thought to be sounds of cracks, creaks and explosions.
but turns out that the sump did indeed crack at the base, no doubt the uneven concrete floor.
the leak is tiny, so will hold for now.
but replacing it with a bigger more efficient sump - frame to sit on the floor to make sure the edges of the sump is supported (thanks David R) for your help in advance :bounce:
sufficed to say, i ddidnt get a good sleep last night - nightmares about the tank.