1. For proper acid neutralization tank maintenance all limestone chips must be replaced within a maximum of two years. This is because the surfaces of the stones becomes crystallized and are no longer effective. In cases where gel or oily type substances develop on the stones surfaces, more frequent changing of the limestone is necessary. If too much of this is occurring, the use of a filtering device prior to the limestone tank would be necessary (such as our sediment interceptors). This is also true if a lot of debris is coming out with the effluent to clog up and cause stoppages in the pipe lines or limestone tank.
   
   
2. Care must be taken not to damage the tank walls or bottom, internal fittings, and gasket on top when taking out old limestone and putting in new.
   
   
3. Always fill the tank with water, up to the bottom of the outlet fitting (lowest fitting). Gently add the proper limestone chips in the manner described in paragraph #3 above. As the limestone is added, some water will overflow out the outlet fitting.
   
   
4. Safety precautions must always be taken. Check with O.S.H.A. requirements. Generally, you should always ventilate the room and/or area prior to opening the tank covers, i.e. open windows, doors, etc. You should wear eye protection and rubber gloves at a minimum. A carbon filter mask and possibly a rubber apron with rubber boots should be used on the larger units. Do not allow sparks, matches, or cigarettes near the units as solvents are often discharged through the units. These can be Flammable or Explosive! Take the old limestone and put it on heavy plastic polyethylene sheeting. Sprinkle baking soda (sodium bicarbonate) all over the old stones. Let them sit there for a few hours to neutralize any residual acids/chemicals still on the stones. Afterwards, wash the stones down with water.
   
   
5. If no toxic chemicals have been discharged through the tanks, you may now (after you have completed paragraph # 5), dump the old stones into a dumpster. If, however, toxic chemicals were used, then the limestone could be contaminated with the toxic chemicals. If this is the case, you must hire a licensed and insured toxic waste disposal service to take the material away and incinerate it. (They must have government approval documents to do this work. If they improperly dispose of your wastes, you could be fined seriously. You must get certificates of insurance from them to cover you.)
   
   
6. When ordering new limestone, order extra bags for maintenance purposes. Every month (or every other month in some cases), you must remove the cover following the safety procedures above and check to see if the level of the limestone has settled or dissolved down. The level must be maintained at the bottom of the outlet fitting. If it is too high, stones will fall out and clog your drain line. If it is too low, you may not be completely neutralizing.
   
   
7. If you have algae growing (a greenish or reddish growth) on your limestone, pour some liquid bleach (such as “Clorox”) on them to kill the algae. Of course, follow paragraph #5 above when working with bleach.