Great to hear. Was thinking a 3 filter setup with a water separator. 30, 10, 2 micron and pulling the oil from the top to the tank, leaving the bottom 6" or so.
That is pretty much how my system works using hydraulic filters. After i fill my converted 25 gallon propane tank, i pressurize it with air and that pushes the oil through the filters instead of using a hydraulic pump. I find it is more efficient than using an electric motor/pump. Plus with air, you can control the oil pressure on your filters. Another key thing i learned with my system is your hydraulic filter bases HAVE TO BE THE KIND WITH NO BYPASS AT ALL. Even a little oil will seep by these bypasses as your filters become more clogged and you will notice it will make you go through filters on your truck. Also, before you fill that tank with oil from the storage tanks, it helps when the oil sits a while before you filter it. this allows all the water and particulates to settle to the bottom of the storage tanks. so don't move those tanks around and let gravity do a lot of your filtering for you.
So lessons learned from my system:
-use hydraulic filer bases with NO BYPASS VALVE AT ALL
-use air pressure to push the oil through your filters. as filters clog/cold temperatures thicken oil, it may filter A LOT slower... maybe even only drip. Air allows you to save money by not using electricity to power a pump and no pump out there will pump only a few drips a minute unless you have pressure relief valves and what not. Air is the best.
-Let gravity do your work. before you fill up your pressure rated tank (converted air tank, propane tank, etc) fill it with oil that has been sitting a while and never pull off the bottom of the tank where the sludge is.
- Put drains and ball valves on everything. If you have a drain on the bottom of a tank and it is a ball valve, put a plug in the other end of the drain ball valve for extra security in case the valve gets bumped. Also these drains on the tanks make a good periodic check to make sure you do not have water in your system.
- If somebody says they have a 55 gallon drum and it has all used oil in it and no water at all.... it will still have water at the bottom. 99% of the time every 55 gallon drum of used oil i have gotten has had water in the bottom. i believe it has to do with condensation of air into water at the top of the oil. warm humid air gets to the to of the cold oil in the drum, it condensates and goes to the bottom of the oil drum. so the key is to cap off these large oil containers.
- Mice love to drown in used oil. I dont know why, but they love to fall in used oil tanks and drown. so screen your before it goes into your tanks if you don't know if there might be a mouse or sludge in the oil bucket. for example: somebody gives you a 5 gallon bucket full of oil. they say it does not have water in it and it is all clean. don't trust them... it will bite you some day. when you pour oil into your holding tanks, pour it through a window screen. you will be amazed at what comes out. its better to catch a dead mouse in a screen than to have it get clogged in a drain valve. Dead mice are NASTY.
I hope this helps. These are all my lessons learned. I am very happy with my system and it took several variants of my design to fine tune it to where I am happy with it. it does cost money to build, but if you do it once and are happy with it, that makes all the difference. If you are happy with it, and it works well, that is the main thing.