Red Flint Gravel 1/4" x 1/8", 50# Bag

Red Flint Gravel 1/4" x 1/8", 50# bag is a fine-graded quartz support gravel that sits between coarse underbedding and the working media in filtration and softening tanks. Its smaller particle size bridges the gap between larger base gravel and fine treatment media, helping hold the bed in place and keeping media out of the distributor slots.

• Screened grade: 1/4" x 1/8" fine particle size
• Supplied in a 50 lb bag (roughly 22.7 kg)
• Dense, high-purity red flint quartz
• Inert and insoluble, so it does not alter water chemistry
• Used as an intermediate gravel layer above coarser support gravel
• Uniform grading reduces fines migration and bed disturbance

Because of its finer sizing, this grade is commonly the upper support layer in a multi-tier gravel underbed, cushioning the media and improving backwash distribution. It works in both residential and commercial mineral tanks. Layer it directly above a 1/2" x 1/4" grade for a graded bed, and refer to your tank's underbedding specification to calculate the correct number of bags for your vessel diameter and height.

The Foundation Under Your Media

Red Flint Gravel is the support bedding that sits at the very bottom of a filter or softener tank, cradling the distributor and holding the finer media above it in place. Poured in around the lower basket or screen, this graded gravel spreads the flow of water evenly across the bottom of the bed so treatment happens uniformly instead of channeling down one path. Its rounded, naturally hard grains resist breaking down and will not react with the water passing through, which is exactly what you want in a layer that stays buried and undisturbed for the life of the tank.

Why a Gravel Underbed Matters

Without a proper support layer, fine media can work its way into the distributor slots, clog the underdrain, and end up in your household water. A gravel base solves that by acting as a graded transition between the coarse distributor openings and the finer media on top. Anyone building a new backwashing filter or softener, or repacking a tank that has been opened for service, will want fresh support gravel laid down first before the working media goes in.

Loading and Support

Getting the amount right depends on your tank size and the media you are running, so we are happy to help you estimate how much support gravel your build needs. This underbed is used alongside a riser tube, lower distributor, and your primary media. We include the guidance we have available, and the Water Softener Plus team can talk you through proper layering and startup so your tank packs correctly the first time.