Bournemouth water Ca and Mg

MrClockOff

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20 Aug 2020
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Bournemouth
Hi there,

I’m looking for someone from Bournemouth who is familiar with the water quality down here. Specifically I’m looking for the values of Ca and Mg. I could buy one of the tests myself but it’s a shame to waste £££ just for single test.
thanks for help 👍
 

dw1305

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7 Apr 2008
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10,645
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nr Bath
Hi all,
Specifically I’m looking for the values of Ca and Mg.
Your water company is probably <"sempcorp Bournemoth Water ">, but you might have <"Wessex Water">? I know some of the (Bournemouth Water) supply is treated chloramine, so that would be useful to know.

In either case your water will be from a chalk aquifer, so it will be <"fully saturated with calcium carbonate"> (CaCO3), and not have much in the way of magnesium (Mg), in it for <"geological reasons">. That is about 18dKH & 18dGH, ~pH 8 and 650 microS. conductivity.

If you are bothered about the derivation of dGH/dKH, then the workings are in the link.
Perfect, you can convert the 137 mg/L CaCO3 value to dKH using: 1dKH = 17.86 mg/L CaCO3 and 137/17.86 = 7.67 dKH. The derivation of dKH etc is in Larry Frank's very useful <"Water Hardness"> article at the Krib.
cheers Darrel
 

MrClockOff

New Member
Joined
20 Aug 2020
Messages
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Location
Bournemouth
Thank you everyone for the input. The reason I’m looking for Ca and Mg levels is the issue I’m currently experiencing with my Hygrophila Compacta which is new growth degradation. Specifically new leaves are growing very thin and translucent from stem towards the tip and also have curling edges upwards. Also it has loads of pinholes in old leaves and they got brittle. Previously roughly 2-3 month ago it was growing like a crazy. So I’m suspecting either Mg or B deficiency. My water is supplied by Bournemouth Water and according to my postcode the hardness is 15dGH which is matching my API test result. One thing I’m not sure about is which value in the report defines the Ca concentration in the water. According to API kH test kit is 9kH.



Let me introduce my fish tank.

It’s 80L but actual volume is 50L. Tank is 80cm width, 35cm height and 35cm deep. It has factory fitted LED lights 9Watt. It has internal filter Eheim BioPower 200 and has CO2 injected through flux bazooka in tank diffuser.

CO2 drop checker is lime color towards yellowish. PH about 7, nitrates 20ppm, phosphates 2ppm, ammonia 0ppm, nitrites 0ppm, 26c temperature. Lights are on for 10hours with 2hours break after first 5hours.

I’m dosing NPK daily:

N - 1.61ppm

P - 0.28ppm

K - 2.53ppm

CSM+B where daily concentration of Fe is 0.04ppm.

Weekly 50% water changes.

Water quality report attached
 

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dw1305

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Joined
7 Apr 2008
Messages
10,645
Location
nr Bath
Hi all,
Specifically new leaves are growing very thin and translucent
Can I ask what colour <"the new leaves"> are?
My water is supplied by Bournemouth Water and according to my postcode the hardness is 15dGH which is matching my API test result. One thing I’m not sure about is which value in the report defines the Ca concentration in the water. According to API kH test kit is 9kH.
That is useful, the dGH and dKH of the water are very likely to the same, because they are both derived from dissolved chalk (CaCO3).

You don't have a quoted calcium (Ca) value, but you can assume that the mean ~ 90 mg/L hardness (dGH) is nearly all calcium.

Have a look at <"How do I work out...."> for a complete explanation, but a quick approximation is 90/0.4 (% Ca in CaCO3) = 225 and 225/17.9 = 12.5 dGH.

If you don't add any magnesium? I definitely would, there isn't really a downside, and you can buy "Epsom Salts" (MgSO4.7H2O) from Ebay, Boots etc. they are 10% magnesium.

I should also have said that because the minimum and maximum NO3 levels are so variable, it will be a blended water supply that sometimes includes some surface water, as well as aquifer water.

cheers Darrel
 

MrClockOff

New Member
Joined
20 Aug 2020
Messages
12
Location
Bournemouth
Can I ask what colour <"the new leaves"> are?

They have a nice green colour but in some areas missing green pigment and you can see through them. Pictures attached

By the way I’m using plain gravel + root tabs
1B6A7167-08CE-4791-A249-FB0444B21661.jpeg
E61B1F01-7B7A-4561-9DBF-199A19E35ADF.jpeg
2F45DC25-6529-4226-902C-C7FB2AADA861.jpeg
 

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