I won't actually recommend this, and too late to help you. I filled my 1000 gal tank with water, added a very low suds detergent, fired the boiler and heated/circulated the water for several hours up to 190F, then drained the tank hot water, rinsed the tank, and used the tank thereafter with a hot water filter installed. Changed the filter multiple times over a one year period, and by the end of about a year the filter no longer was catching anything and not being discolored. That was about 10 years ago, and never have experienced a known problem. I don't actually know how much crud/sludge was in the tank, and I'm thinking that anything non-soluble and heavier than water just sank to the bottom and settled in the tank, no longer a source of any harm.
What is the thickness of the steel in your tanks? From your photos it is difficult to see but appears to me that it is not 3/8" like a 500 gallon propane tank should be. Are you sure they are propane tanks and not fuel oil tanks?got 2 500gal “propane” tanks, were used for fuel storage, full of sludge and years of fuel storage.
There anyway way to easily clean this or just scrap it and move on?
I didn't believe there was much, if any, crud that would circulate after the cleaning I did. And the hot water filter would prevent any solid material getting into the plate hx for the pex in-floor system, which was filled with an antifreeze solution. As for the storage tank, boiler and piping, 10 years have passed and no problem has surfaced. As I said, I don't recommend what I did. There are unknowns that could cause a problem -- just none that I know of for my tank and system.you don't have to worry about the oil getting into your home heating system?
mine is all inside my house with oil boiler back up so i wasn't planning on running any type of additive, except maybe some type of rust prefention treatment.Just clean them.
Some soap and a pressure washer and a little time and you are good to go.
Add a filter to your system, and relax and enjoy the heat.
I have a side-stream filter in my system,but on the glycol side.I used used copper tubing and fittings for most of my system and have Y strainers on each side of my plate heat exchanger.
I replaced the filter after 2 weeks then 2 months and then it's been fine for the last 7 years.
I have valves right at the bottom of my tanks,every year i open them to see if there are any sediments in my tanks.Clean water is all i ever get.