But after messing with the float height and switching to a different flapper (the one it shipped with was junk), it started working a lot better.
That’s been my experience too—sometimes it’s just a tiny adjustment that makes all the difference. I swapped out the factory flapper on ours for a higher quality one and suddenly the half flush actually did its job. I do think you nailed it about bowl and trapway design, though. We had a “budget” model in the guest bath and no amount of tweaking helped. It’s wild how much the engineering matters. I wish more brands would focus on that instead of just slapping a dual-flush button on anything.
It’s wild how much the engineering matters. I wish more brands would focus on that instead of just slapping a dual-flush button on anything.
That’s the truth. I’ve lost count of how many times I’ve been called out to “fix” a half-flush that just never worked right, only to find out it’s not really a fixable issue—it’s just a poorly designed toilet. You can swap flappers, adjust floats, even mess with the fill valve, but if the bowl and trapway aren’t designed for efficient low-volume flushing, you’re fighting a losing battle.
I’ve noticed some brands seem to get it right consistently, while others just don’t. Out of curiosity, has anyone actually had luck with those aftermarket dual-flush conversion kits? I tried one on an older tank a while back, and it was more trouble than it was worth—never could get the timing dialed in so the half flush didn’t just dribble out. Maybe it’s just me, but sometimes it feels like the “upgrade” is more of a downgrade...
if the bowl and trapway aren’t designed for efficient low-volume flushing, you’re fighting a losing battle.
That’s been my experience too. Even with the “universal” kits, it’s hit or miss. Has anyone actually seen a conversion kit work well on a non-dual-flush toilet long-term, or is it always a compromise?
I’ve tried a couple of those conversion kits on older toilets, and honestly, it’s always been a bit of a gamble. Here’s what I found works best if you’re determined to try:
1. Check the bowl’s flush rating—if it’s not designed for low flow, you’ll probably get weak flushes or need to double-flush.
2. Make sure the seal on the kit fits perfectly. Any leaks and you lose pressure.
3. Test it for a week or two. If you’re seeing clogs or leftover waste, it’s probably not worth the water “savings.”
In my case, I ended up swapping out the whole toilet for a WaterSense model. It was a pain upfront, but way less hassle (and mess) in the long run. Sometimes the retrofit just isn’t worth the compromise, especially if you’re worried about backups or leaks.
Half flushes have always been a bit of a mystery in my house too. Tried one of those kits on my ‘90s toilet—ended up with a “half flush” that was more like a quarter flush. My spouse started calling it the “just-for-show flush.” Eventually, I caved and replaced the whole thing. Honestly, sometimes you just gotta accept that not all toilets are meant for modern eco-heroics.
