Originally Posted by
LabRat
Old metal plumbing is old metal plumbing... Dry down some amount of water from when you first turn on a tap in a clear or white vessel and look for black, blue, rust or sand/dirt, or get a iron test kit and test... If you do any plumbing work, look inside the fittings to spot discoloration, corrosion, pitting, run your finger inside and see if it picks up particles... Make sure that there are no different metal fittings or pipes connected directly together, but if you have to, run at least a foot of plastic pipe between to separate those potentials... Use plastic hangers and pipe grommets near valves that connect to metal sinks to make sure feed pipes do not ground directly to sink... If in doubt, replace metal pipes, fittings in the darkroom... Other parts of the system might have dissimilar metal to metal connections, and can be a release source...
Sometimes in worst case situations you might see a brass valve or copper pipe that has severely corroded or turned black on the outside, that is a loud alarm that there is a severe electrolysis problem in your system!!! They make anti-electrolysis coupling fittings for pipes, water heaters etc, but some distance plumbed in plastic works well...
Not trying to be too anal retentive, but one lab had such a collection of metals, that just turning on the water on Tuesday morning would darken a bucket of water, and it turned out that the pipes and fittings were dangerously thin inside, and leaving cloudy water...
Out here in the LA (western) drought, some of the plumbing I fixed over the last few years has suffered due to hard, bad water and seats on valves have gotten really cut up from much particulate grinding them into constant leaking... My film lab water filter had a large handful of sand and swirly dark particles in it after water main construction in my area, just after 1 week of changing the element!!! I drink this stuff!?!!
Steve K
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