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Fluidmaster vs Korky: Toilet Replacement Parts

When I replace toilet parts, I simply want them to work as they’re supposed to, and for a long time.

You might be tempted to just grab the cheapest part from the hardware store.

But why go through replacement all over again when the cheap equipment fails?

I stick with trusted brands that have been making nothing but toilet parts for decades.

So which is better, Fluidmaster or Korky? Read on and I’ll tell you which to pick depending on what part you need.

Fluidmaster 400AH Fill ValveKorky 528MP Fill Valve

Fluidmaster vs Korky Fill Valves

Common problems you’ll see with a bad fill valve:

  • Water runs constantly
  • Weak flush or no flush
  • Noisy fill
  • Tank slow to refill

The fill valve is the most complex part of the toilet. The rest is pretty simple.

Since there are moving parts in a fill valve, it’s really important to go with a quality mechanism.

Both brands skip the old “balloon on a stick” style of valve. Also known as a ballcock fill valve. Yeah, I’m going to stay with “balloon on a stick” for the name. Anyway…

Fluidmaster and Korky both save space inside the tank by eliminating the giant float.

This makes it easier to get to the flapper and chain if you need to make adjustments to those.

Fluidmaster’s float is a cylinder on the outside of the valve. I like this style since it still saves space, but you can see what’s going on with it. The float rises with the water level, and the water supply cuts off when it reaches the top.

Korky uses an internal float. It’s nice and compact, but if it gets stuck inside it’s hard to know what’s going on.

Another difference in these two brands of replacement fill valves is the warranty. The Fluidmaster PerforMAX 400AH has a 7-year warranty versus 5 years for the Korky 528MP QuietFILL Platinum.

Perhaps the extra warranty isn’t a big deal to you on an inexpensive part, but I think it says something about how long it’s expected to last.

My Pick: Fluidmaster PerforMAX 400AH Fill Valve


Fluidmaster 502P21 FlapperKorky 100BP Flapper

Fluidmaster vs Korky Flappers

When a flapper fails, you’ll have one or both of these problems:

  • Water trickles into the bowl constantly
  • Toilet flushes by itself

Fortunately, it’s a cheap and easy fix.

First thing, you’ll need to find out what size of flush valve you have.

2 inch is by far the most common, followed by 3 inch.

3″ is mainly found in newer toilets made in 2005 or later.

To check, take the lid off the tank. If the flapper is the size of a baseball, it’s a 2″ valve, and if it’s nearly the size of a softball it’s a 3″ valve.

To be extra sure, you can measure the diameter of the valve by holding down the handle/flusher until the water has drained. Then, measure the diameter of the plastic valve below the flapper.

Korky also has a handy sizing guide along with a video.

Here are the options:

FluidmasterModel 502P212″
FluidmasterModel 54033″
KorkyModel 100BP2″
KorkyModel 3060BP3″

Both brands have 5 year warranties on these flappers.

They’re both easy to install, though the Fluidmaster pushes into place the easiest of the two.

I’ve also found the Fluidmaster flapper to have a simpler water usage adjustment. The dial is more clearly labeled and easier to turn. Plus, it’s on the top side where you can see it while it’s installed.

My Pick: Fluidmaster Universal PerforMAX Flapper


Wax Rings vs Wax Free Gaskets

For a long time, wax rings were the only option for sealing the area between the toilet and the flange. This seal prevents leaks under the toilet.

Waxless rings are a more recent option.

In terms of providing a good seal, either wax or wax free will work just as well.

Wax rings are cheap and do the job.

So why might you want to instead choose a wax free gasket?

  • They’re reusable, in case you think you might move or replace the toilet soon
  • No Mess
  • They are more forgiving for non-pro installers – you don’t set down the bowl perfectly on the 1st try, you can lift it up and try again
  • A longer warranty is included
  • They’re not sensitive to low or high temperatures, such as in-floor radiant heat
  • They work with most any flange height
Fluidmaster 7530P8 Better Than Wax SealKorky 6000BP WaxFree Seal

The Korky 6000BP WaxFree Seal and the Fluidmaster 7530P8 Better Than Wax Seal are very similar.

They both include all necessary hardware – spacers, brass closet bolts, washers, nuts, and plastic washers to keep the bolts upright.

Both have a 10 year warranty.

There’s one difference that makes me prefer the Korky over the Fluidmaster.

If you think you’d rather go with a rubber seal over wax, I think the Korky 6000BP is best.

The bolt holes on the seal sit lower on the Korky seal than on the Fluidmaster. That makes it easier to insert the bolts and keep them perfectly vertical.

My Pick: Korky 6000BP WaxFree Seal


If you’d rather stick with a traditional wax ring, I’d go with the Fluidmaster 7513. It’s extra thick so it’ll work even if your flange is below floor level.

Fluidmaster 6102 tank to bowl gasket kitKorky 464BP tank to bowl gasket kit

Fluidmaster vs Korky Tank-to-Bowl Gaskets

Have a leak between the toilet and the bowl?

A tank-to-bowl gasket & bolt kit will get you fixed up.

These parts can eventually wear down due to being submerged in water. Unfortunately, a lot of toilet manufacturers cheap out on their hardware and come with bolts or gaskets that wear out faster than they should.

Inside the replacement kits you’ll find a large rubber gasket, bolts, nuts, and washers. Everything you need to mount the tank to the toilet.

Is the Fluidmaster or the Korky kit better?

Fluidmaster uses solid brass bolts, and Korky uses stainless. Neither will rust – they’ll hold up for a long time.

What you want to avoid is cheap, low quality replacement bolts.

Some companies will use brass-plated bolts to save money, but it’s just a matter of time before the plating wears off and they rust away. Then you end up with rusty streaks in your tank – and eventually the bowl.

So again, either the solid brass Fluidmaster bolts or stainless Korky bolts are great. I do like that the Korky kit comes with a 3rd bolt plus nut and washers, so you have spares on hand.

The Korky gasket material is nice and spongy, yet sturdy – the quality feels better to me than the Fluidmaster.

As with replacement flush valves, there’s more than one size of gasket available.

2 inch is by far the most common, with some newer toilets using 3 inch valves. Certain American Standard, Toto, Kohler and other newer toilets use 3″ valves for a more powerful flush. Measure your flush valve to be sure.

Here are the options:

FluidmasterModel 61022″
FluidmasterModel 61103″
KorkyModel 464BP2″
KorkyModel 481BP3″

My Pick: Korky 464BP Tank to Bowl Gasket & Hardware Kit


Other Notes

Korky manufactures their parts in USA, while Fluidmaster parts are made in China and Mexico.

Despite this, Korky’s parts are priced about the same.

If you’re new to toilet repair, no big deal. That’s what YouTube is for, right? It’s really pretty easy.

Just a few things I’d like to note for beginners:

  • Always shut off the water supply valve to the toilet first.
  • Flush out the remaining water. If your water supply is shut off properly, the tank won’t refill.
  • Take the time to fully empty and clean out the tank once you’re working in there. A sponge works well for both soaking up the remaining water and scrubbing.
  • If you’re replacing the wax ring, clean all the excess wax from the flange and beneath the toilet. Wear rubber gloves. Wax is messy.
  • Before you put your wax ring or wax-free seal in place, set the bowl down to test fit it. Make sure it doesn’t rock back and forth. Shim the toilet if needed.

Korky has some nice troubleshooting guides to help you diagnose and fix common problems.


Whether you go with Fluidmaster or Korky, you’ll be getting good quality parts that should last for years.

While you can’t go wrong with either brand, some minor differences set them apart. Check over my recommendations above depending on the part you need.