Can I use Fiber Clear instead of the traditional D.E. in my FNS Plus  Filter?

Yes, that is an acceptable filter media. However, we have found that it tends to need  backwashing much more often than with D.E.

Where is the model number located on my Pentair filter?

The filter's  model number and serial number are on the label on the filter tank. The label has a punched hole indicating the model number of the filter.

I have a D.E. Filter. Why is it that every time I vacuum and run the  filter, I have D.E. on the bottom of the pool an hour  later?

It would be best to vacuum up the D.E. in the pool and then add D.E. if you know how much is in the filter after you do this. If you don't, then vacuum up the D.E., backwash  the filter, and add approx. 80% of the total amount recommended on initial filter D.E. start up. Clean the filter grids well and look closely at them for any holes. The slightest hole can allow D.E. to go through the filter. Also, the  manifold at the top should be examined closely for any cracks or holes. Lastly, check all pipes to see if their associated o-rings are ripped, torn or missing. Replace as needed.

Why is dirt passing through my sand filter?

A number of things could be causing the problem. It could mean that a lateral is cracked or broken, or a valve may need servicing. Or, air may be passing through the filter, causing a channeling effect that permits dirt to get by the filter. In the latter case, there may be nothing wrong with the filter. 

What is the difference between the TRITON* C and the TRITON C-3  filters?

The difference between the TRITON* C and the TRITON C-3 is that the C is a standard bulkhead plumbing 2" connection and the C-3 is a 3" flanged connection.

Is there any way of sealing a leak in a filter tank?

Unfortunately, there is no way to safely seal a leak in a filter tank. The best option is to  replace the tank.

I have a 10 year old sand filter. How can I determine if the sand  needs to be replaced?

The general  recommendation is to backwash your filter when the pressure reaches 10 psi over the initial start up pressure. For example, if the start up pressure is 15psi, you should backwash when the pressure reaches 25psi. If the pressure does not return to the start up pressure after backwashing, it is time to change the sand.