Aussiedistiller, Home Distilling, Moonshine, Home Brew

Hey fellas
I'm doing the macs bwko, had no problems for a coupla years and about 6 of x5 generation goes at it.
2 x 30 litre fermenters with 5 kg of sugar in each and 7 litres of backset in each every time.

This time I may have forgotten the quarter of teaspoon of citric acid.
At the start of the 4th generation 1 fermenter started bubbling out of airlock as normal and the other was very very slow. I added more yeast, waited 2 weeks, distilled them both, all good.
im now at start of 5th gen, i added the citric acid with the backset this time in case that was the cause of the slow start, and now both fermenters are doing nothing after nearly 24hrs, there is no bubbles rising, no foamy stuff on top ,no fizzing sound,nothing at all.
Im pretty sure my yeast is good as I do not disturb the grain bed when racking off the top, I always disolve the sugar in the backset and then wait till cool before adding to the fermenters.
I have never given ph levels a thought as always gone well.
From my research I may have too much backset causing a ph problem, if citric acid didnt sort it what should i try to go the other way?
Anybody got any thoughts?

No need to add citric acid and backset.
The ph will be too low.
Add some calcium carbonate (or other suitable) to raise ph.
Can be sourced from LHBS
Get some ph strips at some stage

Yep no need for citric acid mate, only on first gen. You will probably find that 7 ltrs of backset will be too much by gen 3. I only use 5 ltrs normally.

Try this link
viewtopic.php?f=57&t=11307

Get yourself a pH pen I suspect that will show your problem

Propionic acid builds up over multiple generations too. And as the ph drops, it inhibits the yeast growth. Ph may be a problem, but unless it's under 2.5 Its not the only problem you have.