Once vertical grids are damaged beyond normal use without replacement or repair any chance of maintaining water clarity is diminished. And, as you've seen, replacement can be very costly.

The grids get damaged several ways.

Too much DE or failed to clean old DE out properly before adding new.
Pump too strong
Using Baquacil without special instructions
Letting pressure build too high.
Filter hoses hooked up backwards
"Old Age"

To Repair

Find defective grid, fig A, and repair with Marine JB Weld as follows:

How Bob Would Do It:

If you are the least bit "handy", here's what I would do and have done for my customers that didn't want to spend the money for replacement grids.

Tools required:

Curved Carpet Needle
Heavy Thread (I prefer Dental Floss its pretty strong)
small drill bit
plastic knife (such as from fast food places)
2 part Marine Grade JB Weld Epoxy, or similar product

Prepare Grids:

Clean grids, scrub with a low foaming detergent such a Boraxo or Dishwasher Powder. Rinse well and spray with 50/50 white vinegar and water. Let it soak for a while then rinse and let dry.
Thread your curved carpet needle and stitch any tears together snugly. You just want them to stay together so you can use the epoxy.
For tears at bottom or top edges, drill some small holes through the plastic and stitch the filter material to the plastic edge.
When all this is done mix up some epoxy, start with small amounts to determine working time.
Using the plastic knife...spread thin layers of epoxy over the tears, and threads. It doesn't take much....just enough to cover the threads. Let dry and add another layer if necessary.
Fill the drilled holes in the plastic and you are finished.

Annual Maintenance or As Needed

To Clean and Maintain Vertical Grids:

Remove grids and hose off with best spray from water hose. Inspect grids and determine if any need to be repaired or replaced. Soak in container of cleaning solution from 3-4 hours to overnight. Scrub, rinse with clear water and let dry and store away.

The cleaning solution can be one of the following:

Filter Cleaner from dealer.
1/2 cup of automatic dishwashing compound, such as Cascade per 5 gallons of water.
1 cup TSP (Tri Sodium Phosphate) per 5 gallons of water.
50/50 solution of muriatic acid and water. Note: do not soak elements in muriatic acid if the pool uses Biguanide products or grids are impacted with algae. This will damage the filter. If grids are impacted with algae use the dishwashing solution.

FREQUENTLY ASKED QUESTIONS ABOUT DE FILTERS

My DE filter is running at high pressures and has a slow flow of water returning back to the pool

The DE filter is loaded with too much debris or algae and needs backwashing or regeneration. If this problem persists and you notice the filter gauge pressure rising from 7 - 10 psi above your beginning pressure, you need to regenerate your filter. Refer to your Owner's Guide for further instructions or consult your pool dealer for service.
Your pump output might exceed the design flow rate of the filter. Make sure the pump is correctly sized for your filter.
If there is algae in the pool, super chlorinate, backwash or bump/drain and recharge as needed. Make sure you are properly backwashing on your vertical grid filter. Refer to your Owner's Manuals for instructions.

My DE filter short cycles even after I backwash or regenerate and recharge

The filter elements may be clogged because of an accumulation of chemical deposits. Clogging is accelerated if chemicals are fed through the skimmer, operating your filter too long without DE after starting the pump, or operating the filter without DE. DE must be added as soon as the filter is full of water, and the pump is putting out a steady stream of water. Refer to your Owner's Guide for the amount of DE your filter requires.
Biguanide based sanitizers (i.e. Baquacil, SoftSwim) can cause short cycling.

My DE filter is leaking back into the pool

Be sure that the suspected material on the pool floor is actually DE. Pollen, chemical residue and plaster dust often look like DE.
You may have a tear in your filter elements, replace if necessary. Make sure that you assemble the internal parts properly!
Check for air leaks, as this will cause the system to leak DE back into the pool. If there are air leaks, install a check valve between the pump and the filter valve.

My DE filter has short cycles when vacuuming

This is normal if the pool contains very dirty water. Backwash or regenerate and recharge more often. If there is a presence of live algae, add enough chlorine sanitizer to control this growth, then vacuum. The presence of alum or floc agents will clog the filter. Vacuum so as to bypass the filter. Do not use floc agents with DE filters.

Will backwashing or regenerating my DE filter thoroughly clean my filter?

No, you must thoroughly clean the elements at least once a year. You can clean your filter elements using Filter Cleaner from your dealer or automatic dishwasher detergent. Remove the elements from the filter, according to the instructions in your Owner's Guide, and hose them off with a forceful stream of water from your garden hose. Fill a large plastic container with warm water and add about a 1/2 cup automatic dishwasher detergent or 1 cup Tri Sodium Phosphate (TSP) per 5 gallons of water. Soak the elements for approximately 3 - 4 hours. After soaking, rinse off the elements again. Re-assemble your filter according to the instructions in your Owner's Guide.

You may choose to clean the elements with muratic acid or other commercial filter element cleaners, mix according to the package instructions. Use extreme caution when handling any cleaning agents, as they can be harmful to the eyes, skin and clothing. After cleaning, thoroughly rinse all elements with cold water. Note:do not soak elements in muratic acid if the pool uses Biguanide products or grids are impacted with algae. This will damage the filter.

How often do I need to change the DE?

Whenever you backwash your DE filter allowing the dirt and DE out the waste line or when you regenerate and drain your Perflex filter.