Bead Filter KH Values

[Russ W]

Hi All,

We've all heard it. Minimum KH is 80, Desired KH is 100-120, and if you have a bead filter KH is 175-200.

Some us even believe it.

But how many of us understand it?

Why does a bead filter required a higher KH value to become a viable biological filter???

Russ

[JasonS]

It is not as if it doesn't work at lower KH levels, just that it doesn't work as well as at higher levels.

Likely this is masking the real issue: nitrifying bacteria are just less efficient at lower PH levels.

So the solution: overfilter and turn over the volume of the pond as much as you can.

[Russ W]

Hi Jason,

Thanks for the reply.

You commented "Likely this is masking the real issue: nitrifying bacteria are just less efficient at lower PH levels."

Is this a typo error? Do you mean KH Levels?

Information noted, but you haven't explained why KH values are not recommended at 175-200 for all biological filters. Eveyone wants the most efficient biological filtering no mater what filtering system they use. But the recommended KH value is 100-120 unless it is a bead filter.

Why does a bead filter need higher KH?

Russ

[Nishi8]

It is my understanding that with a bead filter there is less oxygen in the filter and therefore a higher KH level would be beneficial. I have heard that 80 is an absolute minimum, but I have never heard that 100 - 120 is best for a gravity flow and that 175 - 200 is better for bead filters. I have always heard and have practiced keepeng KH levels higher for better function no matter what. Over filtering and increasing turn over rates is not a good solution for lower KH levels. A filter that is more efficient and higher levels of KH is always the best solution.

[Clay]

Love bead filters for their simplicity and ease of use. I plan on having two on the outdoor pond. Contemplating one for the skimmer circuit and one for the midwater pickup circuit. The bottom drains will each have Wave 36 vortex systems.

My comment is that while beads are great they are best used as part of a filter System and less as stand alone units that must do double duty as mechanical and biological units. I like them as mechanical units but like to keep the bio filtration seperate. Just a comment for your consideration.

Rick

[JasonS]

KH and PH are usually tied together. Dangerously low KH means the PH can (and usually will) swing even if it doesn't crash (go below 7.0) and GH even enters into the equation for purposes of keeping PH under control.

But I really don't want to get into all the details here.

By focusing on the KH alone, you are missing the larger picture. No one item will 'fix' a broken system in the same way that increasing filter throughput 'fixes' a pond that is close to PH crash because of a lack of KH. A KH of about 40-60 is typical for many japanese hobbyists. They recommending aren't dumping chemicals into the pond to help the jump filters they use, they instead focus on proper stocking and regular water changes (even flow-through systems).

Even my own KH sticks around 40-60 with almost no GH. I must augment my GH because of my stocking density and the PH swings that occur if I do not. But it really has nothing to do with the bead filter -- it works just fine with my system that also includes a shower filter. My smaller pond uses a cloverleaf and a small shower. Both run low KH because of my tap water although the smaller pond is buffered perfectly well with water changes and oyster shells.

Bottom line -- if the KH of your pond water is the difference between seeing ammonia/nitrites or not then you need to reduce stocking/feeding or increase filtration.

[Mike T]

Russ:

We have been running one of our two bead filters for 3 years now and never had any problems with bio filtration even though our KH is only 59 with a pH of 7.5...

Our readings for ammonia and nitrites have always been zero, some say that this can't be because koi constantly emit ammonia, but that's what the tetra test kits say...

Added DIY Bakki Showers after the beads and our reading got even better, reduced nitrate, with ORP readings in the 350-400 range...

Aloha! Mike

[Clay]

Mike, always knew that you were a very smart man: "Added DIY Bakki Showers after the beads and our reading got even better, reduced nitrate, with ORP readings in the 350-400 range..."

Nice,

Rick