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-)">. 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 / 7.14 = 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 contributing 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).

 

[dw1305]

Hi all,

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).

Not being funny, but just throw it away, it definitely isn't working - <"Testing and What to Test">.

If you want a better test kit? A <"semi-titrimetric kit"> (drop test kit) <"would be better">, but even then you are still talking "ball- park" figures at best.

The problem is that your water company has an analytical lab with hundreds of thousands of pounds worth of kit, a standard methodology and trained scientists to use that equipment, they can get accurate figures, but after that <"we are all struggling">.

cheers Darrel

 

[Andy Pierce]

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

Not being funny, but just throw it away, it definitely isn't working - <"Testing and What to Test">.

Agree this - measuring KH is easy with the right kit, but there are a lot of ways to generate what you think are water chemistry data that don't actually have much connection to reality. If you dig deeper into your water report you might find an actual measurement of alkalinity, but if not the inference from the reported Ca value is probably solid as @dw1305 says. The water report is pretty good except not for pH in my experience. I believe this is because the water company measures the pH of the pressurised water supply with elevated levels of dissolved CO2 - once it comes out of your tap the excess CO2 will outgas and the pH will rise, to in your case something higher than pH 8.0 pH dGH question from water quality report.

@BarrWarr your non-CO2-injected tank is only 4 weeks old... do you have an 'active substrate' e.g. Amazonia Aqua Soil? That might (in part) explain the big disconnect between your water report and your measured values. If that's the case then your water parameters will gradually revert to the depressurised tap water norms over what might be 6-12 months as the aqua soil 'exhausts' itself and no longer actively changes water chemistry. As that happens, you may notice changes in how well your plants are doing as the different water chemistry starts to come into effect. There's not actually much you can do about that other than to just live with it, or to rescape your tank with fresh active substrate.

 

[dw1305]

Hi all,

do you have an 'active substrate' e.g. Amazonia Aqua Soil? That might (in part) explain the big disconnect between your water report and your measured values.

That is a good point <"KH, GH and aquasoil">.

I managed this, in reverse so to speak, by soaking Moler clay cat litter in hard tap water <"Can old tropica soil exposed to hard water raise the KH of soft water?">.

cheers Darrel

 

[BarrWarr]

Yes, I have used Tropica soil. With regards to how my plants will fare over time once the soil exhausts - as I have all ‘easy’ care plants, will they be badly affected? In time, will I need to add root tablets alongside dosing the Tropica premium nutrition?

There is just so much to learn!

 

[dw1305]

Hi all,

With regards to how my plants will fare over time once the soil exhausts - as I have all ‘easy’ care plants, will they be badly affected?

You are likely to see issues with iron (Fe) availability first, as the <"cation exchange capacity"> of the substrate begins to become exhausted.

This is because iron forms a <"lot of insoluble compounds"> in harder, more alkaline water. Have a look at <"What is the “Duckweed Index” all about?">.

In time, will I need to add root tablets alongside dosing the Tropica premium nutrition?

Personally I just dose the water column, have a look at <"Root tab ingredients?">.

cheers Darrel

 

[BarrWarr]

Thanks yet again Darrel. I’ll read up on Iron - should I test for this down the line or just look for physical signs on the plants? I have seen the link to the Iron supplement (Chempack) in your quoted post - would you recommend getting some for when the time comes?

I have made a few changes to my tank the past week but I’m finally happy with the scape now and hardware and I’ll add a pic to my journal at some point.

I’m looking at getting some frogbit to start trying the Duckweed index but I’m going to have to find a way of keeping it out of the flow but still within the reach of the lighting. This is all fun and games!

 

[dw1305]

Hi all,

should I test for this down the line

You can't effectively test for plant available iron (Fe). <"Unscrupulous vendors"> will sell you a kit, but they are just after your money, not your (or your plants) well being.

or just look for physical signs on the plants?

The plants are a really sensitive indicator of whether you have plant available iron, this is because iron isn't mobile within the plant and as soon as it becomes unavailable <"chlorotic new growth occurs">. Have a look at <"Duckweed Index says Nitrogen please?">.

I have seen the link to the Iron supplement (Chempack) in your quoted post - would you recommend getting some for when the time comes?

I probably would. Another other option is some FeEDDHA, which means you can use the <"pink tint method">.

cheers Darrel

 

[BarrWarr]

Ok, thanks. I’ll be completely honest, I’m not the most savvy when it comes to all this chemistry etc. All I’m wanting is to provide everything my plants are going to need to ensure they are healthy and look good. I know it’s a very broad question but is there an ‘all-round’ combination of feeds/ferts that will stand me in good stead until I get more experience?

There are so many links to read and technical info that it’s becoming a little overwhelming tbh.

 

[sparkyweasel]

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

The good news is that you're not doing the test wrong; the bad news is that a lot of people think those strips are not great.

 

[dw1305]

Hi all,

... I know it’s a very broad question but is there an ‘all-round’ combination of feeds/ferts that will stand me in good stead until I get more experience? ...

You can buy an "all in one" fertiliser and dose it as recommended.

@Zeus. Will be able to advise you of which one is the best value for money.

Cheers Darrel

 

[BarrWarr]

Ok, that’s great, thanks. I’ve seen so many different ones, be that ones that contain various things to ones for just iron etc…hopefully @Zeus. will be able to provide some much needed help!

 

[Zeus.]

@Zeus. Will be able to advise you of which one is the best value for money.

The difference between TSN and TNC isn't much in real terms, and both are suitable for low tech tanks

short answer to which is best
TNC works out cheaper

Long Answer - I have used a 100litre tank for this, bigger the tank the more it costs or bigger saving going DIY.

a TSN clone

A TNC Clone


As you can see for a low tech and using a standard dose it isn't worth the effort of DIY ferts esp if tank is 100litre. Much depends on dosage above stranded and size of tank.

TNC can be use in high tech tanks at EI levels but a double-triple dose is advise ( that's x6 above standard), from data below the DIY savings are showing at Nearly £50/year/100litres


Hope that helps