Water Hardness

[Shane]

Hi everyone,

There are many posts on various forums regarding Ammo, 'rites, 'rates & pH.

Yet when it comes to water quality, there appears to be very little spoken about 'Water Hardness'....The correct ranges for different species? How to adjust ( Bicarb Soda etc) How often we should be testing?

Admittedly, I've been very slack in this regard & its not something I've previously tested for.....despite the emphasis on it by the Trout farmer I purchased my fingerlings from last year (especially due to my FT & GB's all being exposed the rainfall).

So, with a hardness test kit due to arrive today (hopefully)
I'm looking for some advice & hope someone can share info or links regarding the following,

1)The correct Water Hardness range for Silver Perch, Eel Tailed Catfish & Rainbow Trout.
2) How often I should be doing a water Hardness test? & should my testing be more frequent in months were I receive more rainfall?

Cheers,
Shane.

[ColinW]

Hi Shane
RupertofOz explains Water Hardnes here: http://www.backyardaquaponics.com/forum/viewtopic.php?f=1&t=7430&p=232077&hilit=water+hardness#p232077

[Shane]

Hi Colin,

Thanks for that link.....as I'm not a member of byap.
Whilst Rupert's post does talk about water hardness, unfortunately his post doesn't really answer the specific questions I posted previously.

Cheers,
Shane.

[Crusty]

Rupe loves to plagiarize from aquarium sites and claim it as his own...
http://aquaticconcepts.thekrib.com/Articles/Water_Chemistry.htm

Anyways, on with the answer...

Unfortunately I don't have anything on catfish though most fresh water species guidelines are very similar.
The answer to your question:
Rainbow Trout
Hardness - 50-100mg/L
Alkalinity - 20-200mg/L

Silver Perch
Hardness - 10-200mg/L
Alkalinity - 20-400mg/L

From - Aquaculture and human consumers of aquatic foods - Primary industries 2000

Generally, you can keep your alkalinity and hardness as close to each other as possible around the 80-120mg/L for both for most fresh water species. You will find this will lend itself to stabilizing your system with the addition of calcium hydroxide every day when you feed.

The most important test outside of your nitrogen, is your alkalinity (kH for the aquarium folks). It is more important than your hardness and it will indicate if you have a hardness problem, which is quite rare as most source water (aside from inland rainwater tanks) is significantly hard (high calcium). Also, maintaining your alkalinity would be a regular part of your maintenance but ultimately up to you how you do this. I would recommend you get yourself an alkalinity test kit.

As far as when you should test, depends on how highly you are stocked. In general terms, if you notice any change in your pH outside your normal system fluctuations, test your alkalinity (adjust if needed), if your alkalinity is below 20mg/L check your hardness (adjust if needed). Do away with the sodium bicarb and replace it with calcium hydroxide (hydrated lime). There is no benefit in loading your system with sodium.

[Shane]

Hi Crusty,

Thanks heaps for your help regarding this info, I struggled to find it anywhere.
Much appreciated.

Cheers,
Shane.