I have 2 oil tanks: one sludged up and the other ran dry. I used a air compressor to blow open the blocked tank. Will the 2 tanks level out?
First answer is that yes they will probably level out.
But whether this recurs depends on the source of the sludge. Simply blowing out the lines once probably will not solve the original problem.
If you can figure out the source of the sludge there may be remedies like settlement filters (like used on swimming pools).
You might also consider a larger size tubing.
Without more information it is difficult to give you a precise answer.
From your explanation, I would recommend that you need to have the tanks flushed out by an oil supply company before the sludge gets into the oil supply line and plugs up the line. My questions to you would be: how old are the tanks, are they in the basement or outside, (if they are outside do you live in a cold climate), Do you buy only quality oil from a reputable dealer (never buy cheap oil from a nobody or sludge is what you will get), if you need to buy oil part way through the winter you should add more oil tanks so you only buy oil in August when oil is the cheapest, Both tanks should be connected at the top and bottom with piping the same size as the pipe taps supplied in the tank (usually 2"), Is the supply line from the oil tanks coming out the top of the tank through a dip tube (never connect the oil supply line to the bottom of the tank or you will get water and sludge in the oil supply line)? If this seems like preaching I am sorry, but I live in "OIL COUNTRY" where many homes use #1 or #2 fuel oil to heat their homes Hope this helps. Oh, and if you need to or want to add more oil tanks check with your local officials and fire marshal to make sure it is allowed in your area.