Best way::
Purchase one to two quarts filter cartridge cleaner. Maybe about $10 – $12 qt. and maybe you can reuse it a couple of times. Use a 32 Gal (approx.) trash can partially fill the trash can — enough to just go over the top of the end support of the grid. Add one qt. of the cleaner. Hose the accumulated debris off the cart. to get as clean as possible using the strongest possible water pressure ( most homes do not have over 90# of water press.) Once the bulk of the dirt is removed put the grid into the trash can of solution and let soak overnight. Next day, spray with jet stream until clean or dirt stops coming off the grid assy. NEVER PUT THE DIRTY GRID IN ANY ACID SOLUTION BEFORE THE ABOVE CLEANING PROCESS. If you do you might as well throw the grid out. You have impregnated the grid fabric with any body oil, cosmetics etc and it will never come out. If after the solution above the grids are still stained you may then briefly use a very mild solution of acid and water mix to remove iron stains and such. These are only cosmetic and don’t seem to affect the performance of the grid. I have done it this way for many years and my grids come out looking as nearly new. And I get a long run out of them. You only need to dip the grids in the acid solution a couple of times briefly.

Answer

THIS IS IMPORTANT: I think I can explain the disparity in the above answers with respect to the varying dilution ratios.

If you are using straight muriatic acid — the same type that you would use to etch concrete, brick, or glass — the MORE DILUTE ratio is probably correct. “Real” muriatic acid is about 30% hydrochloric acid, and rather dangerous stuff. (So strong that my pool guy — even though he sells the stuff — refused to give me verbal advice on its use. “Just read the label” he said… to limit is liability! Alas, there are no “pool filter cleaning” instructions on the side.)

He also suggested a “safer” product — labeled “filter cleaner”. This was mildly acidic, and mostly detergents. Its label suggested a 1-to-3 ratio of product to water. So I propose that accounts for the disparity reported above.

Then, back to “how to use muriatic acid”: I suggest that either dilution will work, and that the less dilution you use (say 1-to-20) then the soaking time will be less…. and the more diluted solution (say 1-to-70) might be more appropriate for 12 or 24 hours. But… the exact “recipe” is something I’m still in search of…

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