My Garn Corrosion Fiasco Part 1

How about Hydrogen Peroxide?

I don't know what an ozone bulb is but I do use an industrial grade ultraviolet lamp system at work to kill bacteria in the potable water system.

To the best of my knowledge O3 does destroy bacteria. UV will kill in strong dosage but it mainly disrupts the genetics of the cell to stop their reproduction capabilities.

My opinion is, the best way to eliminate bio issues is to keep pH high and O2 low.

corrosion......I am with steam man...I have many years experience with steam boilers...the first rule of thumb is if you are laying up the boiler for the non-heating season you should fill it to the top........bacterial corrosion,maybe,but if it was filled with water, it probably would not have been as bad as it was......

I remember my Dad telling me that when he did his stint in the Air Force it was a Court Martial offence not to fill up the fuel tanks of the aircraft, maybe for similar reasons?

i think the main concern with not filling fuel tanks is water would condense on the top of the tank and contaminate the fuel

I would agree 100%.

The small planes I have flown this would make sense [just a regular tank] The military helos I crewed all had collapsible blatter tanks that were self sealing.

Just a personal engineering perspective on the interior coating question. A GARN tank has a lot of surface area, and a lot of intersecting surfaces (end walls, HX piping, fire box, etc.). The amount of temperature variation both in terms of surface to surface Delta T, as well as in overall water temp variation, means that all that steel goes through some substantial expansion and contraction relative to surface area and linear joints (seams). A coating that can handle the extremely high temps of the HX tubing, the flex at the end wall/side intersections, and the growth in wall surface area would have to be one heck of a special material. Inflexible coatings will crack and lead to more nefarious sub-surface corrosion described earlier by Heaterman. Coating the entire interior of a GARN or any other complex boiler is no simple task, nor likely to be consistently effective.

Just my thoughts.

DI water is indeed an effective solvent and will leach material from pretty much whatever it comes in contact with. This leaching increases with temperature and contact time. There is a case for using it for at least part of a system fill-up, however. If you have hard water, you can blend DI or RO water with it in order to bring the total hardness down into the optimal (50 ppm?) range before you start adding chemicals. This will not add Cl- the way a softener will, and can also reduce your initial chemical cost because you are no longer fighting the excess Ca+ and Mg+ in the base water. If you need a quantity of DI water, you can buy or rent a DI resin bed and fill through it for part of the system fill. If you use a lot of make-up water and want to blend that, a small DI vessel can be paired with a mixing valve to produce an ongoing supply at the desired hardness.

Both of these posts are good information and spot on accurate. Thanks to both of you for the clarification!