PH Crash but got finally wigglers

[walton321]

Hi, I've had this red proven pair for a couple of months now that has unsuccessfully spawned at least a dozen times with tap water around 80ppm. I recently installed an RO water filter. and dripped heated RO water directly into the breeding tank. The pair finally had about dozen wigglers for the first time under my watch with water around 20ppm. However the PH dropped to around 4.8 when it is normally around 6.3. I've read about PH crashes and how it can be dangerous, but my pair is still normal, eating, and not skittish. Please advise if I should stay the course with dripping 100% RO water. I just sacrificed the dozen fry so they continue their weekly spawning cycle.

Thanks
Walton