"Work it out to four decimal places, then add 20%."
And don't try to use other people's design spreadsheets, especially not if they have tempting little buttons with illuminating statements like "Button 1" written on them. Put down the mouse and back away from the computer slowly...
Does your nutrient mix contain phosphates? If so, you could replace with phosphoric acid. Even if you don't need phosphates, it generally won't do any harm to the bugs. Some of the organic acids can cause toxicity problems with the bugs, you may need to do a tox test first.
Hi ildarn
Have you tried H2SO4 as an acidifier instead? Have had problems with HCl before with a bacterial process, we found it actually inhibited bug growth.
If you are in the design phases maybe consider using a higher grade steel - 316 or 2205, if you were looking at using 304 originally?
The media referred to sounds like "pall" rings used in some bio-reactors. I am using a combined activated sludge/attached media reactor for destruction of an inorganic pollutant in mine slimes dam discharge streams.
The pall rings or media are 15 - 25 mm diameter plastic rings that the bugs...