Having problems with metal staining. i was told that i should clean the heat exchanger. can i just take off the front header & flush the tubes with some d-lime. Thanks

There is a very specific method for cleaning heat exchanger tubing and using any acidic cleaner could potentially cause damage to the tubing, especially if it is erroded. As to metal staining in your tub... cleaning the heat exchanger is NOT the answer! If the staining is copper, then cleaning the heat exchanger is NOT going to correct the problem!. Your heat exchanger is likely copper and if it is the source of the copper staining, then the problem is NOT the heater, the problem is your water chemistry. In most pool service calls I have done, involving staining from copper or iron, the most common problem was low pH. If your test is showing a pH of lower than 7.2, then add pH increaser (baking soda) based on a base demand test. If after adding the needed amount of pH increaser, the pH remains below 7.2, then perform a pool stabilizer (cyanuric acid) test. If the results show higher than 80ppm, drain at least 50% of the volume and refill and retest again. A high stabilizer level in excess of 100ppm will result in a low pH and cause metals like copper to dissolve and stain the pool. Get the level down to around 30-40ppm if possible. Stabilizer is added to chlorine tablets to help hold chlorine in the water longer. You can unstabilized chlorine, but chlorine consumption is higher as a result. If the staining is copper, you should dismantle and inspect your heater for erosion and possible early stage leaks. Replacing the heat exchanger can be very costly. Proper preventive maintenance and chemistry balance will keep the staining issue under control. There are some products available on the market to assist with balance, staining treatment and overall chemistry control. I suggest looking at products by EasyCare, called Pooltec, Scaletec and Beautec. These may be beneficial for your situation.