deletions | additions       diff --git a/pH Specification.tex b/pH Specification.tex  index f997790..661deb0 100644  --- a/pH Specification.tex  +++ b/pH Specification.tex 
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INSERT FIGURE  The physical interface aspect of the system is made up of three parts, where the parts required to dispense acid into the system are shown below: \subsubsection{Reservoir Selection}  The bath is to contain a 10-litre upper volume limit of electroforming solution, where the concentration of acid is up to 22\%. To maintain this percentage of concentration it has been decided that a high concentrate, low volume of sulphuric acid is required (up to 99\%). It will ensure that the overall volume of the bath stays consistent, compared to addition of a high volume, low concentrate acid to alter the pH of the system.  To achieve this, It has been found that a glass separatory funnel is the ideal component to contain the acid solution [8]. The check valve at the bottom of the funnel allows the funnel to be removed from the system when the acid supply needs to be replenished. It is important that the funnel is removed as refilling could result in acid being spilt on the overall electroforming system, where many components are not resistant to the high concentrations of acid used in the pH control system.  The funnel stop should be removed during operation so that the fluid is able to be gravity fed through the system. Without this, pressure differentials could cause the fluid not to be released into the system linearly.