The 10599000058 is a replacement cap for 100mm diameter brine well tubes, the type fitted inside brine tanks such as the BT300. The cap sits over the top of the well, keeping loose salt out of the float valve chamber below while still allowing the well to do its job. If your existing cap has cracked, gone missing or no longer seats properly, this spare is stocked by WrekinWater so you don't need to replace the whole well assembly.
Technical specifications
| OEM Part Number | 10599000058 |
| Diameter | 100 mm |
| Fits | 100mm brine well tubes, including BT300 type wells |
| Position | Top cap of the brine well |
| Material | Polyethylene |
Symptoms that mean you need this part
- The cap is cracked, split or missing entirely
- Salt is falling into the float valve chamber because the cap no longer seats correctly
- A loose or ill-fitting cap is affecting how the float valve rises and falls
- You're servicing a brine well and want to renew the cap while everything is accessible
Why it fails / why it matters
The brine well cap stops salt from falling directly into the chamber that houses the float valve, which needs to move freely to regulate the water fill level in the tank. If the cap is missing, cracked or has lost its fit, salt and debris can settle around the float and cause it to stick or jam, disrupting the water level and the brine strength drawn at regeneration. Because the cap is a simple, low-cost item, replacing it as soon as it's damaged is far cheaper than dealing with a float valve fault caused by salt contamination.
Why buy this from WrekinWater
WrekinWater has supplied brine tank spares to installers and DIY customers for over 15 years from its Bettisfield, Shropshire base, and stocks small parts like this well cap individually so you're not forced to buy a full well kit for a simple fix. Orders are processed quickly and the business is rated Excellent on Trustpilot.
How to fit it
- Isolate the softener at the bypass valve before opening up the brine tank
- Lift off the old, damaged cap from the top of the brine well tube
- Wipe down the rim of the well to remove any salt residue or debris before fitting the new cap
- Press the new 100mm cap firmly onto the well tube until it seats evenly
- Check the float valve still moves freely beneath the new cap
- Recharge with salt as needed and run a manual regeneration to confirm normal operation
Cap Only for 100mm Brine Well
