The float in the brine tank controls how much water enters the tank before each salt dissolving cycle. If the float sticks low, the brine tank fills short and the next regeneration gets a weak brine. If the float sits high or fails, the tank can overfill, and the salt stays soaked around the clock. Neither problem sets off an alarm, so a short check every few months is the cheapest way to catch it early.
What to look at with the lid off
Check your owner's manual before you open anything, and follow its guidance on whether the control head needs to be powered down for safe access. Then remove the brine tank lid or cover and look at the float assembly before you touch it. Note where the water line sits compared with the fill mark on the tank wall or the level described in the manual. Many units have a marked fill line, and that mark is your reference point for every check after this one.
Lift the float gently and let it drop back. It should move freely on its stem or arm without catching on the tank wall, the brine well, or any crust. Look for these specific problems:
A float that feels hollow, rattles, or has visible water inside the body has a leak and will sink or drift. Replace it rather than trying to dry it out.
A stem or arm that binds, bends, or sits crooked will hold the float at the wrong height even when the float itself is sound.
Debris, salt crust, or sediment under the float can block its travel. Clear it with a soft tool and rinse only if the manual allows it.
If your unit has a separate safety float in the brine well, confirm that it moves freely too. Its job is to shut off the water supply if the brine well is flooded, so a stuck safety float is a real problem, not a cosmetic one.
What a low or high float does to the system
A low float usually shows up as salt that stays dry on top while the water level looks short, and the softener may seem to work for a while before hardness starts to leak through. A high float keeps the salt wet, which can cause clumping and bridging, and the brine tank may look full well past the fill mark. Both conditions are worth fixing before you order salt or call a service visit, because the cause is often a simple mechanical issue.
What to ask the dealer or technician
If you do not have the manual, ask these questions before anyone adjusts the float:
Is the float height adjustable on this model, and if so, where is the adjustment?
What is the target fill level, and can it be written on the service record?
Does this unit have a separate safety float, and where is it located?
Are replacement float parts still available for this model?
A simple quarterly routine
Pick a date on the calendar and do the same four things each time. Confirm the water line against the fill mark. Lift and drop the float and listen for binding. Look for cracks, water inside the float, and crust on the stem. Note anything that changed from the last check. Keeping a short written log makes it easy to see a slow drift before it becomes a failed regeneration, and it gives any technician a clear record to work from.