Help with understanding pH et al

[BarrWarr]

Morning,

I’ve just done some testing on my tank water and I’m not sure if I need to address matters.

I have a journal thread on this website but thought I’d post this query here. So, my tanks pH is coming up paler than the colour for 6.4 (so pH is lower than this) and KH is the same colour as 0d (both are Tetra test kits).

My tap water has pH around 6.8 and KH of 6d.

I use Seachem Prime for water changes. I don’t inject co2.

The tank is almost 4 weeks old and with several ‘easy’ plants.

Are these drops in numbers a concern that need to be remedied?

Many thanks.

 

[dw1305]

Hi all,

Are these drops in numbers a concern that need to be remedied?

Not really, you could try a new test kit? I just think that buffering and pH are <"quite problematic areas">.

So, my tanks pH is coming up paler than the colour for 6.4 (so pH is lower than this) and KH is the same colour as 0d (both are Tetra test kits). ... My tap water has pH around 6.8 and KH of 6d.

So something doesn't quite add up there. In carbonate buffered water the pH goes to ~pH8 once you get more than about 3 dKH. This is the pH equilibrium point of the CO2 ~ carbonate buffer system at atmospheric <"Trends in CO2 - NOAA Global Monitoring Laboratory"> CO2 levels. Have a look at <"What am I doing wrong? Please help"> and linked threads <"CO2 relationship to KH">.

Also water suppliers <"add sodium hydroxide (NaOH)"> to the water supply to raise the pH and <"control "plumbosolvency"">.

So the question is "what does it say on your water report?"

cheers Darrel

 

[BarrWarr]

Thanks as always Darrel. Here’s the latest water quality info I can find from my supplier. Does it help at all?

As long as the differences won’t be a problem for my tank’s inhabitants, I’ll stop worrying about it! I only intend to get some cherry shrimp and maybe some White Cloud Mountain Minnows.

 

[dw1305]

Hi all,

Thanks as always Darrel. Here’s the latest water quality info I can find from my supplier. Does it help at all?

That helps plenty.

So basically it is <"hard, alkaline water"> with a <"fair amount of nitrate (NO3-)2>. A lot of people in E. and SE England will have similar water out of the tap. This is how you can work out the dGH from the calcium (Ca) value <"Water Hardness">

How the conversion factors were derived: (GH)​

By definition, 1dGH = 10 mg/liter CaO

Atomic Weight Ca = 40, O = 16, CaO = 56

So 10 mg/liter CaO contains 40/56 *10 = 7.143 mg/liter of Ca​

So we have 117 / 7.15 = 16.4 dGH. The dKH is likely to be similar for geological reasons.

In some ways once you have the 632 microS. conductivity value (~ 400 ppm TDS), you know the answer. All ions (like the NO3-) will contribute, but a large conductivity value is a strong indication that the majority of those ions are calcium (Ca++) and bicarbonate (2HCO3-).

Cheers Darrel

 

[BarrWarr]

Sorry if I’m being dense but does that mean I have nothing to worry about and should stick with what I’m doing (50% weekly [currently 2x a week for the next two weeks] water changes, dosing 6ml Tropica premium each water change), using Seachem Prime)? Or are there things I need to correct?

I’m not going to try with ‘medium/advanced’ plants but I am looking at possibly trying CO2 and injecting but that will be further down the line.

Many thanks yet again.

 

[dw1305]

Hi all,

but does that mean I have nothing to worry about and should stick with what I’m doing (50% weekly [currently 2x a week for the next two weeks] water changes, dosing 6ml Tropica premium each water change), using Seachem Prime)?

Yes, you are fine. You may find you can reduce the nutrient addition over time.

I’m not going to try with ‘medium/advanced’ plants but I am looking at possibly trying CO2 and injecting but that will be further down the line.

I'm not a CO2 user, but there will be plenty who can advise you.

Many thanks yet again.

I'll add some links to my last post.

Cheers Darrel

 

[sparkyweasel]

KH is the same colour as 0d (both are Tetra test kits)

Isn't it a 'count the drops' test?

 

[BarrWarr]

Isn't it a 'count the drops' test?

No, it is a strip that I dip in the water (it covers a few other things too).