I worked five months last summer for a well established asphalt sealing business located in a large metropolitan area in Tenessee. We used coal tar and did a lot of spraying and squeegee/brush work. Im experienced on well over a hundred residential jobs and a few larger commercial jobs. The individual i worked for was not too strict about following the manufacturers directions on how many gallons of water and the amount of sand to be used. He used star seal and for every 100 gallons of sealer he would add 40 gallons of water and 150 pounds of sand and no additives. The star seal guys tell me he should have used 33 to 34 gallons of water and 300 pounds of sand and some latex per 100 gallons of raw sealer. Im seriously considering going into the aphalt sealing business but right now i dont have the money for what would be called a "proffesional seal coating rig". But what i have found is a 4 ft. wide x 5 ft. tall x 7 ft. long square tank made out of 3/16 inch steel with a open top. I have a buddy who is an excellent welder and he can build a 4 ft. x 7 ft. lid cover with a u-shaped gasket channel that will set down over the top outer edges of the tank and can be ratcheted down tight during sealer transport. Now this is what i need some advice on... Yes i know its a square tank and ill be using coal tar and sand and that would present a problem but i will mainly be doing residential and i will be using a squeegee and will not be spraying. Im wondering if the sand that settles into the bottom corners and edges during the night can be scraped loose with a large straight edge scraper and the bottom of the tank can be done the same way. Should this loosen everything up well enough to allow pumps to take over the mixing details??? I know i will need a wet agregate materials type pump to keep the sealer and sand circulated. I am thinking i will probably need two of these pumps with one on each opposing end of the tank. Both discharges would need to be on the bottom opposite ends of the tank and both intakes near the top opposite ends of the tank. But the question is what size pumps would they need to be and what volume would these pumps need to move per minute. Im sure that coal tar sealer with sand sitting in a square tank for a couple days would be a real bear to mix again.